iem journal 2011

THE JOURNAL OF THE

INSTITUTION OF ENGINEERSMAURITIUS

September 2011

THE JOURNAL OF THE INSTITUTION OF ENGINEERS MAURITIUS

Chief Editor:Dr D K Hurreeram

Note from the EditorsNo responsibility is accepted for the accuracy ofinformation contained in the text, illustrations oradvertisements. The opinions expressed in thearticles are not necessarily those of the Editors or thepublisher.

Distributed free of charge to IEM members andavailable at Rs 200 to non-members.

Front cover photograph:MCB Ebene Photovoltaic

Courtesy:Mauritius Commercial Bank Ltd

Printed by: Cathay Printing Ltd.

ISBN: 978-99949-32-67-2


CONTENTS

page

Editorial Note - Dr Dinesh Kumar Hurreeram 1

Use of Biomass from Municipal Solid Waste as a Source of Renewable Energy in Mauritius - Avinash Susty and Santaram Venkannah 2

MAURICE ILE DURABLE - Nadia Daby Seesaram 11

The LEED Process for the University of Mauritius Hall of Residence - Dr Mahendra Gooroochurn 21

Post-tensioned Coffered Slab at Bagatelle Mall & Hotel - Moustaquim M Lalloo 24

Salient Features of the FIDIC 1999 Conditions of Contract for Construction 29

Changing Trend in Dispute Resolution in the Construction Industry: DisputeAdjudication Boards - Kailash Dabeesingh 35

Safety and Health in the Construction Industry - Claude Wong So 37

Safety in the Construction Industry: Mauritian Perspective - H V Jadav 44

Long-span Bridges in the World : General Review - Juhani VIROLA 50

Addressing Finishing problems in Building Construction - Karl Dulaurent 54

Views on Engineering Education for Developing Mauritius - K Bhujun 57

Implications of Adopting Eurocode 7 for Geotechnical Design - A. Chan Chim Yuk 61


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THE JOURNAL OF THE INSTITUTION OF ENGINEERS MAURITIUS - 2011

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Engineering is thediscipline, art, skill andprofession of acquiring

and applying , social, andpractical knowledge, in order toand build structures, machines,

devices, systems, materials and that safely realizeimprovements to the lives of people (Wikipedia).Another definition of the word is the creativeapplication of scientific principles to design ordevelop structures, machines, apparatus, ormanufacturing processes, or works utilizing themsingly or in combination; or to construct or operatethe same with full cognizance of their design; or toforecast their behavior under specific operatingconditions; all as respects an intended function,economics of operation and safety to life andproperty (Accreditation Board for Engineering andTechnology, US). Based on the above universallyaccepted definitions of the word, engineeringcurricula in universities around the world lay heavyemphasis on the ‘design and build’ competencies ofstudents. These competencies have also been themain pre-requisites for engineers to achieveprofessional status. So far, the use of the definitionin its limited sense has been the norm and has wellserved the profession.

The other required competencies of those whopractice engineering namely ensuring economicvalue, safety and more recently sustainability (notspecifically mentioned in the definitions) haveunfortunately not been sufficiently addressed inengineering curricula. The engineering professiontoday calls for these competences as mandatoryrequirements of practicing engineers. Universitiesin the developed world namely those forming partof the Washington Accord have already reviewedtheir curriculum to address the past shortcomings.We expect our local institutions to follow suit.

The above also calls upon the Institution ofEngineers (Mauritius) to run Continuous

P r o f e s s i o n a lDevelopment (CPD)programmes for thebenefit of theengineering community for building competenciesin value analysis, safe practices and design forsustainability.

Moreover, as Mauritius embarks on the ambitiousgovernment programme of creating more space fortertiary institutions, in engineering among others,it is vital to ensure that the engineeringprogrammes offered by these institutions arealigned to the new norms. A good start would beaccreditation of the programmes in line with theprovisions of the Washington Accord, in contrast tothe current system of accreditation.

The papers presented in this issue specifically bringto light the experience of practicing engineers inthe areas of sustainability, safety, good engineeringpractice and recent developments in the field. Theissues raised are pertinent and confirm the need fora review of our engineering curriculum aspresented above. We are thankful to the authors fortheir valuable contributions. We are glad that theIEM Journal has made its way as a professionalpublication for the engineering community. Wehope it will continue to inspire our colleagues inthe profession to share their experience with therest of the world.

To end, as we continue to provide the IEM Journalfree of charge to IEM members, we wish to put onrecord our gratitude to the sponsors for theirsupport.

Dr Dinesh Kumar Hurreeram

Editorial Note


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1. Introduction

Energy is an essential aspect to the economicdevelopment of any country in the world andwill continue to be an invaluable vector whichwill affect the economic and environmentalsustainability (Republic of Mauritius, 2010). Thedepletion of fossil fuel reserves has promptedmany countries to consider alternativerenewable energy supplies for their survival.Mauritius imported 81% of the total energyrequired (Republic of Mauritius, 2010) in 2009and the remaining 19% came from renewableresources, namely bagasse and hydro. Figure 1shows the primary energy requirement in thepast 10 years.

The rapid economic growth in Mauritius hascaused an increase in the annual wastedisposed in Mauritius reaching 1149 tons dailyfor a total population of 1.28 million in 2009.The number of tourists visiting the islandreached 800, 000 in the same year. With theGovernment’s vision of the achieving a target of2 million tourists by 2015, the waste disposal isexpected to increase even more. Beingdependent on the tourism industry to maintainthe economic growth, it is imperative that

Abstract

Anaerobic Digestion (AD) is an integrated approachthat can be considered to solve three environmentalconcerns in Mauritius: renewable energy, wastemanagement and global warming. AD uses organicfraction of municipal solid waste (OFMSW) to produce‘bio-methane’ gas which can be used in acogeneration unit to generate electricity and usefulthermal energy. Simultaneously, AD will help tominimize the amount of waste disposed at the land-filling station at Mare-Chicose and will contribute todecrease the amount of methane gas emitted by thelandfill. Methane gas is a greenhouse gas (GHG) whichis 30 times more potent than carbon dioxide (CO2). The2 main products of AD are the biogas and a semi-solid,known as the digestate. The latter can be treatedaerobically at a temperature of 55 °C to producecompost, which is a natural fertilizer, used for soilamendment.

An anaerobic digester based on the Drancotechnology, treating 100,000 tons of OFMSWannually, is considered. The AD facility is expected toproduce 32 GWh of electricity yearly. 25% of theelectrical power would be used on-site and theremaining 75% (24 GWh) would be sold on the localgrid. The electricity generated by this facility will beable to supply 10,000 houses with electricity and isexpected to produce 40.3 GWh of useful thermalenergy. The facility would improve the localenvironmental conditions by generating electricityfrom a renewable source. The compost can be sold tocut down the imports on chemical fertilizers. Thisreport shows that generation and sale of electricity tothe local grid only will not be economically feasible.The project would be economically viable provided it isconsidered holistically.

Keywords: Municipal Solid Waste, Bio Fuel,Anaerobic Digestion

Use of Biomass from Municipal Solid Wasteas a Source of Renewable Energy in Mauritius

Avinash Susty1 and Santaram Venkannah2*

1Faculty of Engineering, University of Mauritius2Associate Professor, Faculty of Engineering, University of Mauritius

*Corresponding Author: [email protected]

Figure 1: Primary energy requirement (CSO, 2009)


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everybody in Mauritius aims at protecting theenvironment and sustainable development.

Waste disposal causes environmental and healthproblems. Landfills emit a liquid substrate, knownas leachate, which pollutes nearby lakes andrivers (Peter Kjeldsen et al, 2002). Hydrogensulphide (H2S) is another pollutant which is

emitted from landfills. It is responsible for theputrescible odour around landfills and affects thequality of the air (Electrigaz Technologies Inc,2008). Landfills are also responsible for varioushealth and social concerns. In 2008, thepopulation living close to the landfill (MareChicose) has been relocated 20 km away from theMare-Chicose (L’Express, 2011).

On burning coal or other fossil fuels to generateelectricity, carbon dioxide (CO2) which is the

main source of greenhouse gas (GHG) inMauritius, is emitted to the atmosphere andcontributes to Global Warming. The latter, in turn,is hugely responsible for the climate change.Methane gas, generated from landfills, is a GHGwhich is 30 times more potent than CO2(Electrigaz Technologies Inc, 2008). The higherthe amount of waste disposed of in landfills, thegreater is the methane emission.

In 2007, the concept of Maurice Ile Durable (MID)was proposed by Pr. Joel de Rosnay. One of theobjectives of MID was to cut down thedependence on fossil fuels and invest more onrenewable resources. The aim of this concept is toachieve 65% of the total energy mix byrenewable energy by 2028 (Republic of Mauritius,2010). Various projects have been mentioned butdue to other concerns and most importantly cost,these have not materialized up to now.

This report deals with the feasibility study ofsetting up a waste processing plant to generatebio methane and compost. The benefits of sucha plant to country will be;

· Production of methane to generate

· Reduction of waste disposed of inlandfills

· Reduction of GHG emitted to theatmosphere

· Production of compost

2. Characteristics of Municipal SolidWaste (MSW)

Municipal Solid Waste (MSW), commonly knownas trash or garbage, includes all solid wastes thatare generated from residential, industrial,institutional and commercial establishments. In2009, about 420, 000 tons of solid wastes weredisposed at the landfill station of Mare-Chicose(Republic of Mauritius, 2010). The latter hasgenerated 10, 900 and 35, 600 tons of methane in2007 and 2008 respectively. Since 1997, themethane gas emitted from the landfill stationwas vented out through reticulation pipes andwas not used for energy generation (Republic ofMauritius, 2010). The composition of the MSW isshown in Figure 2.

Each material has different natural moisturecontent (MC) and yields different amount ofbiogas through anaerobic digestion (RISInternational Ltd, 2005).The volume of biogasgenerated by each material depends on thepercentage of volatile solids (VS) present in eachtype of waste product. The VS fraction refers tothe biodegradability of the solid content of eachmaterial, and varies from one waste product tothe other (RIS International Ltd, 2005). FromFigure 2, it is shown that yard and kitchen waste,which are organic, account for 70% of the wastestream. The MC of MSW in Mauritius is around48% to 60% and the calorific value of the mixedwastes around 18 800 kJ/kg on a dry weight basis(Romeela Mohee, 2002).

10% of the total MSW in Mauritius is paper andthe most probable treatment of paper waste isrecycling. However, paper is a source of highamount of cellulose which has a relatively highdigestibility since the manufacturing processremoves a significant amount of lignin present inthe initial wood (Humboldt Waste ManagementAuthority, 2010). The more lignin present to

Figure 2: Characterization of MSW (Romeela Mohee, 2002)


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protect the cellulose from bacterial action, theless cellulose will be available for digestion(Humboldt Waste Management Authority, 2010).

Wastes, with high moisture content, break downvery rapidly to form toxic slurry known asleachate (Humboldt Waste ManagementAuthority, 2010). The latter is a mixture of fourgroups of pollutants, namely dissolved organicmatter, inorganic macro components, heavymetals and xenobiotic organic compounds.Excess rainfalls wash away the leachate whichflows to nearby rivers and pollutes undergroundwater, and surface water (Peter Kjeldsen et al,2002).

Biogas from organic fraction of municipal solidwaste can be obtained by various industrialmethods. A dry single-stage anaerobic digester, aDranco process, treating 100,000 tons of organicfraction of municipal solid waste (OFMSW), will beanalyzed on a large scale basis.

3. Anaerobic Digestion Process

AD technologies are being considered in manyregions around the world. For instant, by the endof 2010, about 200 plants are expected to beoperational in European countries and theyshould able to treat about 6 million tons/year ofMSW and source separated bio-waste (AnaerobicDigestion of MSW In Europe, 2010).

There are several ways to design an AD system.One of the main factors that must be firstconsidered before designing a digester is theamount of waste to be digested. Although allmicrobial decompositions process in the sameway, each plant is unique and should be designedaccording to its own input and economicalparameters. AD process can be classified intothree categories: single stage, multi-stage andbatch. Taking into account the water content ofwaste to be treated, fermentation can be furthercategorized into dry and wet.

Anaerobic digestion (AD) involves a series ofprocesses to break down biodegradable organicmaterials by bacterial decomposition in theabsence of oxygen. The reactions take place in anair-tight sealed cylindrical tank, known as ananaerobic digester. The latter provide anoptimum environment for the microbialdecomposition. The anaerobic microorganismsdegrade the organic matter in the absence of

oxygen to produce primarily carbon dioxide(CO2) and methane (CH4). AD occurs naturally in

places where there is low-oxygen concentrationsuch as marshes, wetlands, and landfills(California Integrated Waste Management Board,2008). AD consists of four main steps, namelyhydrolysis, acidogenesis, acetogenesis andmethanogenesis which are illustrated in Figure 3.

Figure 3: Flowchart of the four anaerobic stages(California Integrated Waste Management Board, 2008)

3.1 Products

The end products of Anaerobic Digestion (AD) ofMSW are mainly biogas and digestate. The biogaspredominately consists of bio-methane andcarbon dioxide gas whereas the digestate is ahumus-like semi solid material. The ratio ofmethane to carbon dioxide and the nature of thedigestate depend on the feedstock used in theanaerobic digestion process (Karen Ostrem,2004).

The percentage of methane in the biogas is in therange 50-70% and depends on the substrate usedin the process. It contains some traces of othergases, such as hydrogen sulphide and ammonia.Before it is used in boilers or in cogenerationplants as fuel, methane is cleaned by a process,known as “Biogas to Biomethane”, which removesimpurities such as carbon dioxide, siloxanes andhydrogen sulphides (Electrigaz Technologies Inc,2008).

The digestate is a thick residual sludge withmoisture content of about 80%. It has an


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unpleasant smell due to the presence ofhydrogen sulphides. To ensure pathogensdestruction in the digestate, a retention time ofat least 15 days is required (Karen Ostrem, 2004).At that time, resulting semi-solid has beendegraded and stabilised. For further use ofdigestate, a process, known as curing, must becarried out in order to produce high qualitycompost. The latter is obtained from dewateringthe residual semi-solid followed by the aerobicpost-treatment. The solid obtained can be usedfertilizers in agricultural lands as it containsammonia which is a rich nutrient suitable for thefertility of the soil (Karen Ostrem, 2004). Theliquid obtained from dewatering can, in turn, berecycled and used for waste pre-treatment or toadjust the moisture content in the reactor. It canalso be used as liquid fertilizers for enrichment ofthe soil.

4. The Proposed System

The Dranco technology was developed byoptimising the digestion process that occurs inlandfills. The technology is a single-stagedigestion technology that works on high-solidsconcentration and at thermophilic conditions(50 °C -55 °C), and can handle more than 40%total solids (Luc De Baere). It uses a retentiontime of 2 to 3 weeks to digest the OFMSW by acontinuous process (Luc De Baere). A Dranco

process produces 0.148 m3/kg of biogas whichcontains 55% of methane on average. TheDranco digestion process will be analysed anddiscussed by considering the E5 dimensions.

4.1 Energy

The Dranco facility is expected to produce 14.8

million m3 of biogas by treating 100,000 tons oforganic fraction of municipal solid waste(OFMSW) annually. Based upon the 63.2 % (A.Susty, 2011) methane content obtainedexperimentally, annual methane production is

estimated to be 9,353,600 m3.

In this study, a cogeneration plant, also known asCombined Heat Power (CHP) will be consideredin order to use methane on a large-scale basis. Byusing gas engines, the CHP plant will generateboth electricity and useful thermal energy for itsown consumption. The surplus of electricity can

be sold on the grid and the surplus of thermalenergy can be used to heat the equipment in thefacility.

4.1.1 Electrical Power

The CHP plant is estimated to generate 35%(Charles Banks, 2009) of electricity from the totalenergy obtained from the total energy producedby the methane gas (Charles Banks, 2009). Thetotal energy obtained from methane would be93.1 GWh per year using a density of 0.717 m /kgand low heating value of 50 MJ/kg. The totalelectrical power generated by 100 000 tons ofOFMSW is therefore 32.6 GWh.

The facility will use 25% of the electricity itproduces. The remaining is sold on the grid(Karen Ostrem, 2004). The surplus 24 GWh issufficient to provide 10,000 houses withelectricity throughout the year, assuming that onaverage, each house uses 200 kWh of electricityper month.

4.1.2 Thermal Energy

The cogeneration plant recuperates 50% of thetotal energy produced and uses it as thermalenergy. The latter is used to heat equipmentsuch as the digester and the composting hall.The reactor consumes a large amount of thermalenergy to keep the substrate at a constanttemperature of 55°C. For this design, it is

assumed that 1 ton of substrate occupies 1m3 byvolume. 2862 MJ of thermal energy is required to

heat 1600 m3 of substrate at a constanttemperature 36.9 °C for 1 hour (Jacques deGunzbourg). Hence, amount of thermal energyrequired to heat 303 tons of fresh OFMSW perday is 5.3 MWh per day (1.78 GWh per year).

The overall process produces 173.5 tons ofdigestate per day (refer to figure 4.0). The latter isaerobically heated at thermophilic temperatureof 55°C in a closed hall. Energy required heat thedigester for 24 hours is 1.02 GWh per year. Themixture of 303 tons of substrate and 606 tonsrecyclate in the mixing is preheated at atemperature of about 33°C and this processrequires 3.20 GWh per year. There is an excess of40.6 GWh per year.

It is found that the composting hall and the


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reactor consume only 12.6% of the thermalenergy generated by plant and it is assumed thatthe heat exchangers consume 13% of the totalheat generated (E. Hugot, 1986). The remaining74.4% can be used as a source of heat to provideair-conditioning of some parts in the facility,such as server rooms, offices and mess room bymeans of heat pumps. The surplus of heat canalso be used for district air-conditioning.However, a high investment cost will be requiredfor piping installations.

4.2 Engineering

To achieve the mentioned electrical power andthermal energy, the plant should be equippedwith the appropriate engineeringequipment. Due to lack of information onthe size of individual equipment of an ADfacility, the sizing was done bycalculating the mass balance of the plant.

Figure 4 shows a schematic diagram ofthe proposed AD facility which specifiesthe mass balance across the mainequipment. The size of the digester isestimated to be 7000 m3.

After the production of methane, thelatter is stored temporarily in the biogasholder before it is used in the co-generation plant where the gas isconverted into electricity and thermalenergy. It is shown by above calculationsthat the plants generate 32 GWh per year, that is,4.04 MW per hour. 2 gas engines of 3MWh and2MWh are needed to generate that amount ofelectrical power.

4.3 Economics

Before considering such a project, it is essentialto work the cost benefit analysis to determinewhether is viable or not. Due to lack ofinformation and details on the individual cost ofequipment used in an AD facility which treats100,000 tons of waste per year, some of theequipment costs are estimated by scalingmethod (MAX. S. PETERS and KLAUS. D.TIMMERHAUS) and the rest are estimated fromexisting plants.

When designing a plant, 2 main costs, namelydirect and indirect costs, must be considered.

Direct cost includes cost of raw materials, labourand equipment. Indirect cost includesadministrative salaries, production anddistribution cost and inter-plant communicationcost (MAX. S. PETERS and KLAUS. D.TIMMERHAUS). Table 1 shows the main costs forthe AD plant.

The tipping fee, also known as gate fee, is thecharge levied per ton of waste being processedby the AD facility. The tipping fee is based on aproposed incinerator project (L’Express, 2011)which has been dropped due to environmentalconcern. The same tipping fee can be estimatedfor this project since it is dealing with a wastemanagement program which will reduce thevolume of waste in Mauritius.

Table 1: The Cost and Expected Income

The average price of electricity in France is about€ 0.1215 per kWh (Rs. 5.10 per kWh) (Europe’sEnergy Portal, 2010) and the price of electricityfrom biogas is estimated at € 0.14 per kWh (Rs.5.88 per kWh) (Christian, Coututrier). The price ofelectricity in Mauritius is Rs. 5.98 (€ 0.142) perkWh. By extrapolation, the price of electricityfrom biogas can be estimated at Rs. 7.00 (€ 0.17).The selling cost of compost is based on theaverage price of compost sold at different placesin Mauritius.


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4.3.1 Payback Period

The payback period for three different scenarioshas been considered and is summarized in Table 2below. The tipping fee will greatly help inreducing the payback period but in all three casesthe system will recover its cost sooner or later.

4.4 Environment

The strongest argument to adopt anaerobicdigestion (AD) of organic fraction of municipalsolid waste (OFMSW) is that it gives a solution tomanage waste and to produce renewable energysimultaneously in Mauritius. By treating 100, 000tons of OFMSW, an AD facility reduces the totalwaste disposed at Mare Chicose annually byapproximately 25%. Therefore, there is less use oflandfill and consequently the amount of methaneemitted by the putrescible waste is reduced.Methane is considered as a greenhouse housegas (GHG) which is 30 times more potent than

carbon dioxide and it contributes largely toGlobal Warming (Martin Heimann, 2010). All theproducts of AD have precious end uses and thereis no waste produced.

The water quality is enhanced when the volumeof waste in landfills is reduced. Landfills generate

pollutants in the form of chlorinated solids,sulphides and ammonia which dissolves inleachate that can contaminates nearby rivers,lakes and reservoirs (Karen Ostrem, 2004). Byadopting an AD facility, this problem will be

reduced. The air quality also will be better whenthe volume of waste is shrunk. Putrescible wasteemits a bad smell due to high concentration ofhydrogen sulphide which affects people living inthe nearby locality The odor emitted by thelandfill attracts mosquitoes and rats which areconsidered as potential disease vectors.

The electricity generated by the combustion ofmethane in the cogeneration plant is consideredas ‘green’ and no net carbon is emitted in theatmosphere. Coal produces 0.0856 kg of CO2 per1 MJ of energy (Energy kids). Hence, the use ofmethane instead of coal as fuel to produceelectrical and thermal energy would represent an

Figure 4: Schematic diagram of the proposed AD plant

Scenario Price of electricity/Rs Tipping fee/Rs Payback/Years1 7.00 (€ 0.17) 1100 (€ 26.20) 5.32 5.00 (€ 0.12) 1100 (€ 26.20) 6.43 7.00 (€ 0.17) 0 8.7

Table 2: Payback Period for Different Scenario


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annual reduction of about 28,720 tons of CO2

equivalent. Compared to fuel oil, the annualreduction of CO2 would be approximately 22,975tons (Energy kids).

The digestate which is the by-product of the AD isdried to form compost which is used as organicfertilizers. It also reduces the dependency onchemical fertilizers which causes eutrophicationwhen washed away in rivers and lakes. Mauritiusimports about 57,169 tons of fertilizers in 2009(CSO, 2009).

4.5 Ethics

The community relation is an important factorthat must be considered before proceeding witha large scale plant. An AD facility will offer severalbenefits to the community. By decreasingapproximately 25% of the total waste disposed,more land will be available for further use. Forexample, the space can be used to plant trees andflowers to improve the quality of air and to give apleasant landscape view.

The facility will create approximately 50 to 60direct jobs which will give opportunities topeople with different qualifications to get jobs. Ifthe AD facility is designed with an eye toaesthetics, the place will attract tourists and localvisitors who will be also beneficial to the locality.The plant might organize fun fairs, educationalcompetitions and also might give scholarships towell-deserved students. The plant may organizetours to arise people awareness to sustainabledevelopment.

The partnership of an AD facility is veryimportant. Investors, workers, private and publicsectors, and NGOs must establish a cooperativework in order for such a project to be successful.

5. Conclusions

Anaerobic digestion (AD) is a proven techniqueand technology to treat municipal solid waste(MSW) to produce methane gas which generatesa ‘clean’ and ‘green’ energy. AD will offer Mauritiusthe opportunity to take the lead in sustainablewaste and energy management which willcontribute in the concept of Maurice Ile Durable(MID) and will help to substitute fossil fuels byrenewable resources.

As waste is converted into usable products, ADplays an essential role in the reduce-reuse-recyclestrategy. The priorities of waste management donot change with the adoption of AD. Preventionand reduction is still the primary focus. Only afterthese options have been exhausted should AD beconsidered in a way such that the plant isbeneficial to the environment and community. Byreducing the amount of waste, greenhousemethane gas is also reduced, thus contributing tominimize Global Warming. The carbon dioxidereleased to the atmosphere is considered as‘green’ which will not be at the detriment of theenvironment. Compost, which is a naturalfertilizer, will reduce dependence on chemicalfertilizers in agricultural lands and will maintainan ecological balance. Compared to otherprojects, like incineration MSW, this project doesnot produce toxins as by-products. Undesirableby-products like H2S, siloxanes and water vaporare treated or scrubbed.

By treating 100,000 tons of OFMSW yearly, the AD

facility would produce 9,353,600 m3 of methanegas which will generate 32 GWh of electricity and40.6 GWh of heat annually. The AD plant will useapproximately 25% of the electrical and thermalpower it will produce. The remaining 24 GWh ofelectricity can be sold to the grid and theremaining 75% of the thermal energy can be usedfor air conditioning by using heat pumps. 32 GWhof electricity will substitute approximately 2,867tons of fuel oil or 4,439 tons of coal annually. 24GWh of electricity that would be sold on the gridwould provide 10, 000 houses with electricalpower per year.

The project is economically viable provided thatthe AD technology is analyzed holistically.Composting plays an important role in theeconomic feasibility of the plant as it is the largestsource of income of the whole process. Tippingfee also contributes to a certain extent to the


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economy of the plant. Without the tipping fee,the payback would be around 8.7 years. The factthat the AD facility will reduce the amount ofwaste in landfills, tipping fee must be considered.

To conclude, an integrated approach, taking intoaccount the political and socio-economic aspectstogether with environmental issues, will have tobe adopted for the success of such a project inMauritius. A Private Public Partnership (PPP)might be the key for the success of such a project.The anaerobic digestion of municipal solid wastewill be one of the steps to achieve the MIDobjectives.

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Peter Kjeldsen, Morton A. Barlaz, Alix P. Rooker, Anders Baun,Anna Ledin and Thomas H. Christensen, 2002.Present andLong-Term Composition of MSW Landfill Leachate. Report.North Carolina State University [online]. Available on:http://people.engr.ncsu.edu/barlaz/resources/leachate_composition_review.pdf (Accessed on 14 January 2011)

Republic of Mauritius, 2010. Mauritius Strategy forImplementation National Assessment Report, 2010 [online].Available from:www.sidsnet.org/msi_5/docs/nars/AIMS/Mauritius-MSI-NAR2010.pdf (Accessed 14 January 2011)

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Romeela Mohee, 2002. Assessing the recovery potential ofsolid waste in Mauritius [online]. Mauritius. Available from:http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDX-458PB74-5&_user=10&_coverDate=07/31/2002&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=6906347c665d22a8944a6f037358aa58&searchtype=a (Accessed on 14 January 2011)

MAURICE ILE DURABLE


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Nadia DABY SEESARAM, Ingénieur Environnement-ESIGEC,MIEM

[email protected]

Avant-propos

Le but de cet article n’est pas d’écrire un n-ièmearticle sur le concept Maurice Ile Durable (MID)mais en priorité d’informer les lecteurs de l’édition2011 du Journal publié par l’Institution desIngénieurs de Maurice (IEM) de l’avancement duprocessus MID tel que certains de nos membresl’ont suivi à ce jour.

Cet article utilise volontairement le français etl’anglais, symbole de la dualité linguistique denotre pays, car si le concept « Maurice Ile Durable» fur lancé en français sur la base du « Grenelle del’Environnement », les rapports subséquentsfurent rédigés en anglais du fait que la langueofficielle de la République de Maurice estl’Anglais.

Introduction

Le concept Maurice Ile Durable fut lancé en 2008par le Premier Ministre de la République deMaurice, Navinchandra Ramgoolam, telle unevision à longue terme pour le développementdurable de notre pays.

L’objectif principal du concept MID est de faire dela République de Maurice un modèle mondial dedéveloppement durable, et ce particulièrementdans le contexte des petit états insulaires en voiede développement (SIDS: Small IslandDeveloping States).

Si la force motrice initiale était axée sur l’énergie –vers une minimisation de la dépense énergétiquede Maurice en ressources fossiles par le biaisd’énergies renouvelables et vers une utilisation

plus efficace de notre énergie de manièregénérale, le concept MID s’élargit rapidementpour inclure tous les aspects du modèleéconomique, de la société et de l’environnementconsidérés comme étant le pivot de notre quêted’une Ile Maurice durable.

Le Déroulé du Processus MID

Février 2010

Une consultation nationale est lancée en Février2010 avec pour double but l’élaboration du «Green Paper » qui détaille et incarne les besoins etles aspirations des Mauriciens et ledéveloppement d’une vision partagée du MID.

Le « Green Paper »est soumis par le professeurOdendal en Avril 2011 et le Cabinet ministériel estmis au courant du contenu du rapport.

Avril 2011

Un « Draft National MID Vision » est rédigé, validépar le comité de pilotage (Steering Committee) etles avis de la société civile recherchés.

Monsieur Claude WONG SO, « Fellow Member »de l’Institution des Ingénieurs a le privilège desiéger sur ce comité.

Le gouvernement souhaite développer unepolitique concrète du MID, une stratégiedécennale du MID et un plan d’action détaillé duMID pour ouvrir la voie à un développementdurable du pays.


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Juin-Juillet 2011

Première phase consacrée au dialogue et àl’élaboration des propositions au sein desgroupes

Sur le modèle du Grenelle de l’Environnement, sixgroupes de travail ont été mis sur pied; ils sontconstitués de représentants des collèges quiavaient pour vocation de représenter les acteursdu développement durable : les Ministères, lesCorps paraétatiques, le secteur publique, lasociété civile ainsi que d’autres associations.

Les six groupes de travail ont pour thème :

L’Institution des Ingénieurs est appelée par leMinistère de l’Environnement et leDéveloppement Durable à participer auxgroupes de travail WG1, WG2 et WG3 et nommeM. Aboo Bakar PEERMAMODE, ingénieurélectrique, à l’Energie et Mlle Nadia DABYSEESARAM, ingénieur Environnement, àl’Environnement.

Les groupes de travail se réuniront quatre fois àdeux semaines d’intervalle pour débattre desproblématiques liées à leurs thèmes spécifiques.Appel est ensuite fait aux membres pourparticiper à des réunions supplémentaires vers lafin du processus afin de contribuer à validation durapport.

L’objectif des groupes de travail est d’identifier lesvoies et moyens d’atteindre « la vision partagéedu MID » et d’énoncer des recommandationsconcrètes sur chacun des thèmes définis pouralimenter le processus de formulation d’unepolitique, d’une stratégie et d’un plan d’action duMID.

Les groupes de travail ont eu à leur disposition lesdocuments de base telles que le « Green Paper »,le « Mauritius Environmental Outlook Report »

ainsi que les politiques et stratégies sectoriellespour entamer leur réflexion.

Août 2011

Les rapports compilés par les rapporteurs desdifférents groupes de travail sont complétés etrendus.

L’avis général des groupes de travail dans lesquelsIEM est intervenu est que notre pays dispose ducadre légal relativement adéquate pour la miseen application de nombreuses recommandationsdu MID mais l’application des lois fait défaut etdoit être renforcée.

Les cinq secteurs clés abordés lors des ateliers detravail, pour mémoire Energie, Environnement,Emploi, Education et Equité sont fortementinterconnectés et l’évolution des uns ne va passans celui des autres.

Il ressort aussi de ces ateliers de travail queMaurice Ile Durable devrait se lire « Maurice IlesDurables » afin de prendre en compte la spécifiéde la République de Maurice constituée des sesdifférentes îles.

Au-delà

Il appartient maintenant aux consultantsnommés sur processus d’appel d’offre à formulerune politique et stratégie du MID qui serontvalidés par le « Steering Committee » et par lesgroupes de travail, qui seront rappelés à la tâcheen Novembre 2011.

L’objectif ultime est la mise en application du pland’action décennal MID en Mars 2012 pour lapériode Mars 2012-Mars 2022.

L’Institution des Ingénieurs de Mauricecontinuera à participer au processus du MID ettiendra ses membres informés du déroulé àtravers son site internet : et à travers sesparutions.

Retrouvez toutes les informations sur leprocessus Maurice Ile Durable sur le site officiel :

Les résumés du « Green Paper » et du « Mauritius EnvironmentalOutlook Report » sont annexés à cet article. Les documents completspeuvent être téléchargés entre autre du site officiel du MID :http://www.mid.gov.mu

WG1 : Energie

WG2 : Environnement : Préservation de laBiodiversité et des ressources naturelles

WG3 : Environnement : Pollution, déchets etenvironnement

WG4 : Emploi

WG5 : Education

WG6 : Equité


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PRÉSENTATION DU GRENELLEENVIRONNEMENT

Partant du constat que la France traversait unecrise climatique et écologique de grandeampleur, le Président de la République, NicolasSarkozy, a initié le Grenelle Environnement, dès le21 mai 2007.

Le Grenelle Environnement réunit pour lapremière fois, l’Etat et les représentants de lasociété civile afin de définir une feuille de routeen faveur de l’écologie, du développement et del’aménagement durables.

Le déroulé du Grenelle Environnement

> Du 16 juillet à fin septembre 2007 : premièrephase consacrée au dialogue et à l’élaborationdes propositions au sein des groupes

Les 6 groupes de travail ont été constitués dereprésentants de 5 collèges qui avaient pourvocation de représenter les acteurs dudéveloppement durable : l’État, les collectivitéslocales, les ONG, les employeurs et les salariés.

· groupe « lutter contre les changementsclimatiques et maîtriser la demanded’énergie » : il s’intéresse aux transports, àl’aménagement, à la construction, à l’habitatet à l’énergie ;

· groupe « préserver la biodiversité etles ressources naturelles » : il traite de l’eau,des espaces protégés, et inclura la pêche et lesressources halieutiques ;

· groupe « instaurer un environnementrespectueux de la santé » : il analyse lesenjeux liés la santé : qualité de l’alimentation,pollutions, déchets, qualité de l’air ….

· groupe « adopter des modes deproduction et de consommation durables »: il travaille sur l’agriculture, l’agroalimentaire,la pêche, la forêt, la distribution et ledéveloppement durable des territoires ;

· groupe « construire une démocratieécologique » : il s’attache à débattre d’uneréforme des institutions pour prendre encompte le pilier environnemental dudéveloppement durable, comment améliorerl’accès à l’information….

· groupe « promouvoir des modes dedéveloppement écologiques favorables à

l’emploi et à la compétitivité » : il aborde lesquestions de recherche, innovation, emploi,fiscalité écologique, publicité responsable …

Ces groupes de travail ont remis leurspropositions le 27 septembre 2007.

> Fin septembre - mi octobre 2007 :consultation du public

Le public a été consulté via des réunionspubliques, des forums internet. :

· 14 000 contributions sur Internet ont étérecensées

· 300 000 internautes sont intervenus sur leforum du Grenelle

· 15 000 personnes ont été présentes aucours des 19 réunions régionales organisées.

> Mercredi 24 et jeudi 25 octobre 2007, tablesrondes et annonces des conclusions duGrenelle Environnement

A la suite des tables rondes organisées autour dequatre demi-journées de travail, le Président de laRépublique, Nicolas Sarkozy a annoncé lesconclusions du Grenelle Environnement.

Le Grenelle Environnement permet d’aboutir à268 engagements en faveur de l’environnement.

> En décembre 2007, lancement des 34comités opérationnels

Le Ministre d’État a lancé 34 comitésopérationnels, pilotés par un parlementaire ouune personnalité reconnue, dont la mission étaitde proposer des actions concrètes pour la mise enœuvre des engagements. Les travaux se sont,pour la plupart, achevés en mai 2008 pour laisserla place au « temps du Parlement ».

> Entre 2008 et 2010, les lois “Grenelle”

Le Parlement a adopté les textes nécessaires à latraduction législative des engagements duGrenelle Environnement.

Retrouvez toutes les informations sur le Grenellede l’Environnement sur le site officiel

http://www.legrenelle-environnement.fr/


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MAURICE ILE DURABLE - GREEN PAPER

TOWARDS A NATIONAL POLICY FOR A SUSTAINABLE MAURITIUS

Executive Summary

1. Never before has it been as necessary and as urgent for Mauritius to review the directions in which

the country is moving. Profound and far-reaching changes are sweeping across the globe, some of

them forerunners of future shocks that will dramatically impact on the quality of life. Intense

unfavourable impacts are already being felt at the local level in many countries and Mauritius should

by no means consider itself immune. Resource depletion, climate change, overpopulation,

diminishing conventional energy source, deforestation, pollution on land and sea, rising poverty

world-wide, and political instability, are only some of the factors that we now need to confront, and

hopefully can overcome.

2. As a Small Island Developing State (SIDS), Mauritius is exceptionally vulnerable. It faces similar

threats to its survival as other SIDS, which include, inter alia, a strong reliance on a depleting natural

resource base, loss of biodiversity and degradation of essential components of the ecosystem, and a

heavy dependency on fossil fuels and other imported commodities that support society. Climate

change, the long distances that separate Mauritius from Africa and Asia, coupled with rising fuel costs

exacerbate the situation considerably. Unless substantial and effective interventions are put in place

soonest, the current and future generations may not be able to meet their needs.

3. Mauritius is responding to the global and national challenge of achieving sustainable development

through the implementation of the Maurice Ile Durable concept that was brought to the nation by the

Prime Minister of the Republic of Mauritius, Dr. The Hon. Navinchandra Ramgoolam, GCSK, in

2008, as a long term vision for the sustainable development of our country. However, it was soon

realised that, in order to formalise a coherent and coordinated response to the formidable challenges

that we face, a comprehensive and overarching National Policy for a Sustainable Mauritius will be

required, a policy that is accompanied by a MID Strategy and MID Action Plan.

4. The formulation of the policy comes at the right time. The comprehensive National Environmental

Strategies for the Republic of Mauritius: National Environmental Action Plan for the Next Decade

was published in 1999. In the subsequent decade our country has seen unprecedented economic

growth, bringing benefits to many people while at the same time putting additional strain on our

resources. While there are many plans and policies that govern our development, there exists not a

single document that addresses all pillars of sustainable development in the same integrated manner

that the current policy will aim to do, and none that will have the same solid grounding in public

consultation and expert opinion.

5. True to our democratic tradition that evolved since Independence, and in line with the principles of

good governance, a policy formulation process was designed with the involvement of a range of

parties, including civil society, the private sector, Government bodies, NGOs and Special Interest

Groups. The aim of the policy, together with the strategy and action plan would be to attain “a

situation in which the needs of the present generation are met, without jeopardising the chances of

future generations to meet theirs”. The policy process was endorsed by Cabinet in 2009, and the

nation participated enthusiastically in the short time made available before the oncoming 2010

elections called for a recess in public consultation.

6. The Green Paper comes at the end of Phase 1, and summarises the policy formulation process up to

this point, in particular the results of the national consultations that were launched in February 2010.

Ministries, Special Interest Groups and civil society at large were consulted through a variety of

methods, including a National Youth Summit that was held in April 2010. The national consultations

yielded rich results, summarised in section 6, which is testimony of a society that has a good grasp of

what the pursuit of a Sustainable Mauritius would entail. Input can now be examined in depth during

thematic workshops to be held in Phase 2 of the policy process, while a Draft National Vision may

function as a guiding light on the road that lies ahead.

7. A wide range of issues were identified that relate to the conventional three dimensions of

sustainability, namely the economy, environment, and social issues. Most significantly, and rather


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unexpectedly, a fourth one dimension, namely governance, was identified in the classification of

issues:

Proportion of views expressed by the population classified into the four categories

8. The four dimensions of sustainable development can

be further divided into thirty-six themes, out of

which eighteen were identified as priority themes

after analysis. They are all deemed important and

worthy of in-depth exploration, especially when it

comes to identifying discrete actions and

programmes for the MID Action Plan. The

breakdown of input into the priority themes is shown

in the figure below (note again the high percentage

attributed to governance issues):

Breakdown of input into the priority

themes

9. One message that clearly stands

out from Phase 1 is that the needs and

aspirations of the people, and their

National Vision, do not differ

significantly from how Government

views sustainability and how the

Ministries see their mandates in

relation to sustainable pursuits.

Coordination, transparency and

integrated governance are at the top of

the list of good governance indicators

that were discussed. Without

integrated governance it will be very

difficult if not impossible to balance

the needs and mandates of different

sectors which, when viewed on their

own, all have valid reasons to take

priority. Finding the balance and

solutions will require an overarching,

coordinating and legal and integrated

framework, which is what may be

expected from the National Policy for a

Sustainable Mauritius.

10. Institutional analysis and legal

review can greatly improve the

efficacy of the Government machinery.

Without better mechanisms of

coordination and cooperative decision

making, integrated development

planning or devolution of powers to

lower tiers of governments, will remain

difficult. Fortunately, achieving higher

levels of good governance should not

be too difficult in a country that has the


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highest scores for governance in Africa. Thorough institutional analysis and legal review ought to

reveal what adjustments, additions and potential institutional reforms (they are expected to be small

but nonetheless very important) may be necessary to make Government stronger in pursuing

integrated solutions and in making decisions that will achieve better balances when economic, social

and environmental, and even cultural issues are at play.

11. A Draft National Vision emanated from the National Youth Summit (see section 9). There is also a

longer Draft Combined National Vision that is made up from all the draft visions from the different

meetings. It is proposed that the two visions are published in the press for further comment. This will

confirm that all Mauritians had a chance to contribute to the National Vision. Visioning exercises

must continue with the further consultations proposed in section 10. When all comments and draft

visions have been collected the Draft National Vision can be further refined. It will then be included

in the Draft White Paper, which effectively is the Draft Policy. When the White Paper is endorsed by

Cabinet as the National Policy for a Sustainable Mauritius, the National Vision will be embedded in

it.

12. A gap analysis of the policy formulation process up until the Green Paper reveals suggestions that

may be usefully applied to the implementation of Phase 2. The Policy will relate strongly to

governance issues and overall directions, while the Strategy may be expected to define discreet areas

of intervention, and an Action Plan with budget that will describe actions and indicate how much

investment will be needed in the coming years to achieve a Sustainable Mauritius.

13. It is stressed that the policy process as approved by Cabinet must be strictly adhered to, up to the point

where the White Paper is endorsed as the National Policy for a Sustainable Mauritius. The necessary

institutional analyses and legal review should not wait until the policy is already in an advanced stage;

all consultations have pointed very clearly to the need for a legal review and improved institutional

relationships that will lead to higher levels of integrated governance. Deviations and ad hoc

alterations to the process, including pre-determined thematic workshops that do not strongly correlate

with the input of the people (see also section 11.3) must be avoided. Deviations can lead to

suboptimal results and may inadvertently damage the integrity of a landmark process that can rightly

be described as a remarkable example of Government planning with the people. All gaps in the

consultation process as initially planned should be filled. Only then can ownership be fully shared by

all Mauritians, and will this be a policy that belongs to all of us.

Mauritius Environmental Outlook Report

Key Messages for Decision-Makers

The environmental assets of Mauritius are the key to present and future socio-economic progress and it is

time to realise that development should not take place at the expense of the environment. For national

development to be meaningful and beneficial, actions should be taken to reduce the impacts of drivers of

environmental change and to devote resources to implement existing policies and strategies.

Key questions arising from the Mauritius Environment Outlook Report

§ How is the environment important for social and economic development and how can wemake better use of the value of our environmental resources?

§ How is the environment changing and what threats and opportunities does that pose forprogress?

§ What can be done to reduce the operation of adverse drivers and pressures on naturalresources and enhance the potential of the environment by improving prevention, adaptation and

rehabilitation?

§ What special hotspots need immediate attention to halt disasters or irremediable damage?

§ How will fresh polices and better implementation enhance opportunities and promotebetter results and what resources are required?

§ What must be done now and in the next twenty years to ensure that by 2030 environmentalquality is enhanced to support social and economic development?


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Air

· Emissions from industries and vehicles are

causing localised air pollution problems, which

must be addressed urgently.

· The future air quality management process

should adopt an integrated approach including

air quality monitoring methods and standards

as well as air improvement targets in different

sectors.

· Emerging issues such as indoor air quality,

environment workplace risks and the impact of

acid rain should be investigated.

Freshwater

· Mauritius is a water-stressed country, faces

water scarcity problems during dry seasons and

water quality continues to be at risk of being

impacted by effluents and solid waste

generated from domestic, industrial and

agricultural activities.

· To reduce potential pollution from effluents,

efforts should strive to meet the aim of

connecting 80% of the population to the

sewerage network by 2033.

· Given that water demand is expected to rise

with future development and that water

scarcity problems may aggravate with climate

change, it is imperative to increase water

collection, storage and reduce water losses

through the distribution system to 25% by

2030.

Land

· Over the next ten years at least 12,200 hectares

of land will be needed for urban, business and

infrastructural development.

· The transition towards sustainable land

management will require reforms in planning

guidelines to include emerging issues such as

additional requirements for space for housing,

hotel development and infrastructure, waste

disposal and the impacts of sea level rise.

· Enforcement of planning guidelines and the

framework legislation on land use planning

should be strengthened.

Waste Management

· Taking into account the projected growth in

number of residents and tourists as well as

increasing patterns of consumption and

production, it is expected that total waste

generation will increase by about 50% by 2030.

· There is an urgent need to adopt an integrated

waste management strategy and legislation to

promote waste reduction, reuse, sorting and

recycling.

Coastal and Marine Resources

· The coastal belt is already under stress. Careful

exploitation of the coastal zone is essential to

maintain the integrity of valuable coastal and

marine resources.

· Enhancing the quality of coastal and marine

resources entails stricter enforcement of

regulations and adherence of coastal

development to planning guidelines.

· Recommendations of the Integrated Coastal

Zone Management Framework and the

Environmentally Sensitive Areas Study should

be implemented with emphasis on the six

pressure zones: Grand Baie, Ile D’Ambre, Le

Morne, Belle Mare, South Coast of Mauritius

and East Coast of Rodrigues.

Inland Biodiversity

· Ecosystems provide numerous goods and

services like climate balance, regeneration of

soils, catchment protection through forests,

rivers and wetlands, carbon sequestration and

food security.

· Mauritius has the third most endangered

terrestrial flora in the world and invasive alien

species are among the most serious threats to

native biodiversity.

· More investment and collaborative efforts

should be made to conserve native biodiversity.

Energy

· Currently, around 80% of energy is derived

from imported fossil fuels. The prospect of two

million tourists by 2015 and major economic

investment programmes will place additional

demands for energy.

· The challenge is to remove structural barriers

impeding further development of renewable

energy and increase the share of renewable

energy to 35% or more by 2025. The use of

innovative and clean technologies should also

be explored and promoted across all sectors.

· Energy efficiency and conservation

programmes should be further promoted across

all sectors.


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Climate Change

· Climate change effects are already evident in

Mauritius with increases in average

temperatures, declining rainfall, sea level rise

and more extreme weather events in the sub-

region.

· Coastal resources, biodiversity, water

resources, agriculture and fisheries are already

under stress and highly vulnerable to climate

change. Human wellbeing and security of

livelihoods are also at risk.

· Climate change must be mainstreamed into

core development policies, strategies and

plans. In addition, National Climate Change

Adaptation and Mitigation Strategies and

Action Plans should be developed and

implemented.

Offshore Islets

· The 49 offshore islets surrounding Mauritius

harbour many endangered endemic species and

have great conservation potential due to their

unique native flora and fauna.

· Necessary resources should be allocated for the

implementation of the Islets National Park

Strategic Plan and islet-specific management

plans to restore, conserve and sustain the

integrity and natural biodiversity of islets.

· Leasing of islets should be done in a

transparent manner. Lessees should also

participate in islets conservation and protection

for long term sustainability.

Tourism and Environment

· Tourism development will continue to depend

on coastal resources.

· The annual target of two million tourists by

2015 challenges the future of the already

fragile coastal zone. As a result, future

development should be done in due respect of

the environment.

· The tourism industry should be encouraged to

establish Environment Management Systems

and adopt carbon-offset programmes to reduce

their impacts on the environment.

Chemicals and Hazardous Waste

Chemicals

· Chemicals pose a threat to human health and

the environment. However, data on chemicals

use and their impacts is lacking.

· It is imperative to establish a chemical profile

for Mauritius and improve management of

chemicals.

Hazardous waste

· Hazardous wastes pose a risk to the

environment and human health. Thus, a stricter

control regime is required.

· A comprehensive strategy encompassing all

hazardous waste types and a storage facility are

essential for better management of hazardous

waste.

Rodrigues

· Sustainable management of solid waste,

coastal and marine resources, land, agriculture

and water is primordial for the economic and

social progress of Rodrigues.

· Recycling rates have to be increased and can be

done mainly through composting.

· The physical development strategy and the

local plan must be implemented to control land

use. Soil erosion needs to be further controlled

as this is affecting marine ecosystems and

biodiversity.

· Water storage, distribution and management

need to be improved urgently.

· Legislation needs to be strengthened and

effectively enforced for better protection of

marine resources.

Agalega and St. Brandon

· There are still major improvements to be made

to protect the natural resources of Agalega and

St. Brandon.

· The 2004 Blueprint for St. Brandon should be

implemented.

· Land, biodiversity, solid waste and wastewater

management plans should be developed for the

Outer Islands.

· The opportunities for sustainable development

on the Outer Islands are immense and should

be fully tapped.


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LEED stands for Leadership in Energy andEnvironmental Design, a green building ratingsystem devised by the U.S. Green Building Council(USGBC) [1], and currently operated by the GreenBuilding Certification Institute (GBCI) [2]. Itprovides third-party validation for the ‘greenness’of a building, and gives a much-needed objectivedefinition of how sustainable a project is. TheLEED rating system has been around since March2000, and it has since been modified andextended to address the specific sustainabilitygoals of a broad range of projects, including newconstructions and major renovations, schools,homes, core and shell buildings, tenant fit-outs,neighbourhood development and operation andmaintenance of existing premises. The ratingsystem currently awards a maximum of 100points for credits grouped into five categories(Sustainable Sites, Water Efficiency, Energy andAtmosphere, Materials and Resources and IndoorEnvironmental Quality) with an additional 10bonus points available for Innovation in Designand Regional Priority categories. The possiblecertification levels are: LEED Certified (40-49points), LEED Silver (50-59 points), LEED Gold (60-79 points) and LEED Platinum (80 points andabove).

LEED has been gaining international recognition,with the USGBC reporting LEED projectsregistered/certified in 41 countries [1]. Mauritiusis in the process of having its first LEED certifiedproject, which is the Hall of Residence of theUniversity of Mauritius, targeting a LEED Goldrating. The project consists of student rooms,visitor rooms and an administrative area as well as

common rooms, laundry, kitchens and toiletfacilities. The project has successfully cleared thedesign review phase with 54 points plus apotential of 27 points to be reviewed andawarded at the end of the construction phase.

The key to sustainable design and development isan integrated approach within the project team,right at the outset [3]. To show this difference inapproach over the conventional way of managingprojects, LEED calls for an integrated approach inthe design, called the pre-design stage. This stageoffers a unique opportunity for the project teamto set sustainability goals and coordinate thework of all the design team members, so that thebuilding operates optimally. Even if this mayseem an additional workload for the team, thefact that these various early coordinationmeetings would have identified and sorted all theissues pertaining to conflicts between the worksof the different professionals, the subsequentstages have a greater likelihood to progresssmoothly compared to the conventional case. Anadded motivation is that this synergy has thepotential to reduce the upfront costs ofequipment and the recurring operating costs, forinstance, a reduced envelope gain leads to asmaller HVAC plant, thus less initial investment aswell as less energy consumption for cooling. Thesame applies to minimising the installed lightingpower density. The savings are assessed by life-cycle costing analyses early in the project toguide the project team in their decision making.

This integrated approach was found to be a veryeffective way to promote seamless integration of

The LEED Process for the Universityof Mauritius Hall of Residence

Dr Mahendra Gooroochurn LEED AP BD+C MIETHead of Sustainability, [email protected]


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the building elements for the UoM Hall ofResidence project. The efforts expended duringthe pre-design phase paid dividend as thesolutions engineered during the concept anddetailed design phases were highly optimisedand cross-disciplinary. The targeted certificationlevel is a LEED Gold, with a LEED Platinumdeemed to be possible with additional effort atconstruction stage for credits pertaining toconstruction waste management andprocurement of materials to foster recycling,reuse, rapidly renewable materials, certifiedwood and regional materials. This shall bemonitored by on site clerk of works andhopefully secured with the collaboration of themain contractor.

Among the different categories of LEED, Energyand Atmosphere (EA) gets the biggest share ofpoints, which shows the high importanceattributed to designing the building energysystems to operate efficiently for reducingenergy consumption and for curtailing thenegative impact of greenhouse and ozonedepleting gases. The latter requirement was fullyconsidered by using a lithium bromide/watermix for acting as the refrigerant of theabsorption chiller. The application of buildingenergy modelling as an analysis tool throughoutthe design process was a highlight of thisproject; the early building energy and dynamicsimulations were used to determine the buildinglayout and orientation as well as designarchitectural features e.g. details of overhangs atrelevant locations and type of glazing andconstruction for different segments of thebuilding, all in an effort to reduce fabric heatgains

An ASHRAE 90.1-2007 Appendix G performancerating simulation [4] was run and an 18%improvement over the baseline was obtained.Additionally, a measurement and verification(M&V) plan [5] would be devised for the building,which coupled with the energy monitoringdevices included in the design, would provide tofacilities management an effective means toconstantly track energy use and quickly takecorrective measures when appropriate. Thesame strategy has been implemented for wateruse. The selected water fixtures resulted in 40%improvement in indoor water use over theEnergy Policy Act (EPAct) of 1992 baseline.

Rainwater harvesting and on-site wastewatertreatment helped achieve the water efficientlandscaping and innovative wastewatertechnologies, with exemplary performanceobtained in the latter. Based on the creditsachieved, a case was made for the obtention offour bonus points for regional priority, whichwere awarded for the Water EfficientLandscaping, Innovative WastewaterTechnologies, Water Use Reduction andOptimize Energy Performance credits.

The certification process thus far has involvednumerous discussions with the GBCI, both forcustomising the sustainability measuresformulated in the different credits to the localcontext and to ensure the alignment of theproposed sustainability measures with the intentof these credits. Lack of data has been one of thedifficulties in the design and documentation ofcertain credits. In this regard, further work isbeing done with the GBCI to find out alternativesfor compliance and successful documentation ofthese credits both to help earn the associatedpoints for the UoM project and in view not topenalising future projects aiming for LEEDcertification. One of the credits where thisproblem was faced was for the SSc6.1Stormwater Design – Quantity Control credit [3],where data for 1- and 2-year 24-hour designstorms are required but not currently availablefor Mauritius; extrapolations was needed onlonger periods available data to determine thesevalues. It is felt that interesting research projectscan be devised with the goal to collect orgenerate the missing data for enabling accuratedesign of sustainability measures, both withinthe context of LEED or any other certificationscheme, if not for a general sustainabilityframework. Soil thermal properties for ground-coupled geothermal systems design and windand solar maps are other examples of useful datathat would contribute to better green designs.

A summary of the sustainability featuresincorporated in the UoM Hall of Residenceproject is as follows:

The orientation of the building has beenoptimized so as to minimise heat gains andconsequently the cooling capacity of theHVAC system. External solar shadingdevices and double glazing windows have


23

been specified over specific area of thebuilding façade to further minimise thecooling load.

An absorption chiller system has beenproposed for the air conditioningrequirements of the office area and thevisitor rooms. The hot water requirementfor the absorption chiller and domesticpurposes would be met by solar waterheating systems. The student rooms havebeen engineered to be naturally ventilatedspaces using a stack effect and wind-operated roof ventilator.

Lighting requirements (internal andexternal) have been met by using energyefficient fixtures, controlled by lightingcontrollers to provide lighting whenrequired.

Water efficient fixtures have been specifiedfor flush and flow appliances so as to reducethe potable water demand. Rainwaterharvesting has been implemented in theproject, both as a means to manage stormwater to reduce run-off from the site and tofully satisfy the irrigation requirements forthe landscape. The landscape would becomposed of native/adapted plants topromote biodiversity and reduce irrigationdemand.

An on-site Sewer Treatment Plant (STP) hasbeen designed to treat 100% of the sewerand wastewater generated to tertiarystandards, thus relaxing the burden on thesewer network. The reclaimed wastewaterwould be used to fully satisfy the waterrequirements for toilet and urinal flushing.

The hardscape and roof materials havebeen specified to have high Solar ReflectiveIndex (SRI).

The pedestrian and parking areas would beconstructed of inter-locking blocks topromote infiltration of storm water therebyreducing the quantity and rate of run-off.

Conclusion The reliance on fossil fuels for the production ofenergy has been the predominant cause ofabnormal levels of carbon dioxide in ouratmosphere, which has been described as aharbinger of serious threats calamities, both interms of natural and human tribulations; thedisappearance of Maldives in less than 100 yearsdue to a rising sea level is the ultimate exampleto testify for the adverse effect of globalwarming. This calls for each and everyone to dohis/her share to reduce the negative impacts, ifnot reverse this trend of increasing carbondioxide concentrations. The building sector hasmuch to do in this regard as it accounts for asmuch as half of carbon emissions [3]. This can beachieved by designing green, with anunderpinning integrated approach as this hasbeen proven to lead to reduced energyconsumption and even better occupant comfort.This integrated approach can be made possibleonly by the participation of all the professionalsconcerned at the outset, so that highlyoptimised and synergistic solutions can beengineered. The LEED rating system is one of theframeworks of green building principles which aproject team can adopt as guidance toincorporate sustainability measures and achievethird-party validation of the greenness of theproject. The contribution of the USGBC isacknowledged on a number of issues to makeLEED adaptable and more easily applicable tothe Mauritian context, which has seen theirsuccessful implementation in the UoM Hall ofResidence project. The work with USGBC willcontinue on other issues that would make theframework easier to apply and documented forthe local context.

References[1] www.usgbc.org

[2] www.gbci.org

[3] LEED Reference Guide for Green Building Design andConstruction, 2009 Edition

[4] ANSI/ASHRAE/IESNA Standard 90.1-2007, “EnergyStandard for Buildings Except Low-Rise ResidentialBuildings”, ISSN 1041-2336

[5] International Performance Measurement & VerificationProtocol, “Concepts and Options for Determining EnergySavings in New Construction”, Volume III, April 2003


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Post-tensioned Coffered Slab at Bagatelle Mall & Hotel

Moustaquim M Lalloo, Senior Site Engineer, Rehm [email protected]

Outline on Post-Tensioning

Post-tensioning is a method of prestressingconcrete to overcome its natural weakness intension by reinforcing the material with highstrength steel strands, commonly known astendons. This method of construction exists intwo main types, namely bonded and unbondedpost-tensioned concrete. At Bagatelle Mall andHotel Project, Ø15.2mm P.E. coated unbondedtendons with characteristic strength 1862N/mm2

have been used to post-tension 530mm thickcoffered slabs. The tendon in itself consists of anassembly of anchorages, gripping wedges andthe strand.

Strict quality control is the basis for post-tensioning works and the need for specializedequipments and skills are required to carry outsuch activity. However, the principle is simple.Imagine a series of vertically standing books thatneeds to be lifted. While positioning the hands atthe right location and by applying a compressiveforce through pressing tightly against the booksat the extreme edges, one can lift them. Hencepost-tensioning is a construction method wherecompression stresses are intentionally induced tobalance tensile stresses by tensioning thetendons with hydraulic jacks that push againstthe concrete at end anchorages.

Rehm Grinaker’s involvement in Post-tensioning WorksThroughout its 20 years of existence, RehmGrinaker Construction Company hascontinuously endeavored to promote use of

latest construction techniques with respect toprojects’ requirements. In the field of post-tensioning, Rehm Grinaker has acquiredsignificant experience for its involvement duringthe years on projects where such technique wasnecessitated. Manhattan shopping complex,Ebene fly-overs and most recently Port Louis RingRoad bridge decks are a few examples whereRehm Grinaker has carried out post tensioningworks. Though specialized knowledge andexpertise are required, post-tension constructionmethod has been adopted for coffered slabs atBagatelle Mall and Hotel Project as it is known forits multiple advantages. With the support ofAmsteele Systems (Pty) Ltd, which are licensedsuppliers of CCL Stressing Systems, approximately13000m2 out of 15000m2 of post-tensionedcoffered slabs have to-date been cast at BagatelleMall and Hotel.

The Concept of Post-tensioning for BagatelleThe surface area of Bagatelle Mall and Hotelamounts to 45000m2 of concrete slab. At tenderstage, it seemed quite unrealistic to cover sucharea with in-situ conventional concrete slabswithin 10 months. In this context, Mr. RajenGopaul, Contracts Manager at Bagatelle, broughtforward the concept of post-tensioned cofferedslab in order to meet this tight schedule. Hence,the total surface coverage of slab was divided intoin-situ, precast and post-tensioned coffered slabs.Persuaded for the gain in time and decrease incost of operation and resources, post-tensioningconcept was approved by the client andconsultants. This method has impacted positivelyon the program of works, as a result of which


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ongoing extensions have been designed toallow for about 3000m2 additional post-tensioned coffered slabs.

Sequence of Activities1.0 Construction Drawings Approved Amsteele Systems Drawings that

include rebars and tendons details are issuedfor construction.

Coffer layout of a particular slab fromapproved Amsteele Systems Drawings isverified against structural roof layout and anyother relevant drawings under consideration,and discrepancies (if any) are notified andhenceforth corrected. Once receipt andverification of construction drawings areacknowledged, the following isimplemented:

Ø Cutting schedule of tendons

Ø Rebar cutting and bendingschedule

2.0 Materials Preparation Tendons are cut as per cutting schedule and

pre-blocked with dead end anchors usingopen-throat hydraulic jack. An extra length of300mm to 500mm is added to the cuttinglength of each individual tendon for stressingoperation. This extra length projects out ofconcrete edge at live anchors to allow forSS200 stressing jack to properly hold thetendon with its wedge gripping mechanism.Once pre-blocking is done, each tendon isindividually rolled for ease of transfer.

Rebar are cut and bent as per schedules. It ishowever to be noted that somereinforcement are cut and bend on the spotto account for slight site adjustments.

3.0 Deck Preparation Bi-directional reference lines of coffers are set

out as per coffer layout where dimensionalaccuracy of column heads and supportbeams are respected for links and otherreinforcement to fit in as specified and asshown in relevant construction drawings.

Construction joint (if any) is consideredduring staging phase where deck platform isextended at least 5.0m beyond stop end. Thisplatform is used to unroll the tendons.

Access platform of not less than 1.0m wide

must be provided all along periphery of slab,guardrail and toe boards are to be placed forsafety. Access platform should actually bekept until stressing of tendons and groutingof live end anchors are completed. Note thatat this stage, actual extension of tendonsmust satisfy corresponding allowablecalculated extension so that projection oftendons could be cut.

Location of dead and live anchors to bechecked and side shutters to be placed underthe following conditions:

Ø At dead anchor, side shutters canbe placed either before or afterreinforcement is fixed in place withrespect to site conditions.

Ø At live anchor, however, timberor plywood or any other material,that can be drilled to allow forprojection of tendons, should beplaced as side shutters. Generally,dead and live anchors are fixed atneutral axis depth. This factor shouldbe considered prior to shuttering.

At construction joint, stop ends should haveslots to allow for tendons to run through atvaried heights with respect to tendonprofiles. Location of stop ends should be inline with center of coffer and not along rib.

Coffer boxes and deck must be cleaned andlubricated prior to steel fixing.

4.0 Reinforcement and tendon fixing Prior to fixing of rebars and tendons, all M&E

features to be clearly marked. Where suchfeatures’ proposed locations lie along tendonalignment, an alternative measure should besought to relocate them. It should be notedthat fixing of electrical boxing, etc. on top ofcoffer boxes is discouraged since concretecover requirements could be hindered. AllM&E features respect the specified concretecover to any rebar and tendon and theyshould not be tied and/or fixed to tendons.

Profiling of tendons start following fixing ofbottom bars and links to ribs and beams.Tendons generally run across compressionzones.

Dead and live anchors must be properly tiedtogether with bursting reinforcement.


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5.0 Post concreting procedures Following removal of side shutters, live

anchors must be cleaned and prepared forstressing.

A minimum of 12Nos concrete cubes to becast for each pour for cube crushing test to becarried out as follows:

Ø Day 3 or 4 testing – minimum of3nos cubes to be tested to check forminimum strength of 18MPa.

Ø Day 7 testing – minimum of 3noscubes to be tested to monitorstrength

Ø Day 28 testing – minimum of3nos cubes to be tested to confirmcharacteristic strength of concrete

With a minimum concrete characteristicstrength of 18MPa, stressing of tendons canproceed. This is done with the use of SS200hydraulic jack at slab edge or with the open-throat jack for intermediate stressing atconstruction joints.

Once extension of each individual tendon isfound satisfactory, projection of tendons arecut and live anchors are epoxy grouted.

6.0 Safety requirements Safety requirements are to be strictly adhered

to during the whole process for posttensioned coffered slab.

No drilling and/or breaking of concrete to ribsand beams are allowed.

It must be ensured that the deck is safe foraccess after application of demoulding agentand appropriate warning signs must bedisplayed at appropriate locations.

While untying tendon coil on deck, the areashould be cleared.

No activity must be carried out and no personshould be present in the line of a tendonbeing stressed and restricted access enforcedwithin stressing zone.

7.0 Special precautions Concrete must be properly placed and

compacted to achieve sound and free fromvoid concrete around the anchors.

Rebars and tendons must be maintained intheir respective correct position before andduring concreting.

No displacement must be brought to tendonswhile using poker vibrator during casting.

The slab must be free from loading beforepost-tensioning.

The Contractor should ensure that no tendonincluding the P.E. coating is damaged duringformwork striking and hacking of concrete atconstruction joints.

Props along construction joint must bemaintained until the succeeding pour isstressed.

The specified cover must be respected atbottom, side of coffers and edge shutters, andtop of slab.

Before concreting, all tendons must bemeasured and lengths recorded. Location ofdead anchors should be marked for post-casting re-localisation in the event of tendonre-measurement for stress data computationand analysis.

ADVANTAGES OF POST-TENSIONEDCOFFERED SLAB

Post-tensioned coffered slab has a directimplication on design of large areas of slabsfor Bagatelle Mall and Hotel. Records haveshown significant savings in terms of time,materials, resources and operations. From theconstruction point of view, the followingsfactors illustrate the various advantagesencounter with the use of post-tensioning atBagatelle.

Casting of large surface area of slab can beachieved. The maximum effective area ofcoffered slab cast at one pour was of 900m2.

Continuous span over 52m long from oneend to the other was achieved. In structuralterms, this is much more efficient than havingslab spanning from one column to the next.

Longer clear spans can be reached. Forinstance slab spanning continuously on 13mbetween support columns was attained.

Decrease in dead load due to a reduction inconcrete volume. A 530mm thick cofferedslab can be equated to a flat slab 350mmthick. Thus 0.27m3/m2 of concrete used forthe post tensioned coffered slab as compared

to 0.35m3/m2 of concrete for an equivalent350mm thick flat slab resulted in about 23%of overall concrete saving.


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The maximum weight of steel, includingreinforced mesh, used in post-tensionedcoffered slab has been under 15Kg/ m2 ascompared to the 350mm thick flat slab wherereinforcement ranges between 40 to 50Kg/m2.

Reduction in slab weight and achievement oflonger clear spans significantly decrease thenumber of foundations and support columns.

Reduction in materials handling andoperations as the lighter the structure, thelesser support works are required. This alsoprovided a reduction of man-power ascompared to that of a conventional slab.

Support beams had been omitted, therebyeliminating shuttering and steel fixingoperations.

There has been a significant decrease inconstruction time with respect to the actualarea of coffered slab.

With the use of Quick Beam System, cofferboxes were removed two days afterconcreting the slab. This allowed their use inan uninterrupted manner.

The slabs are stressed at day 4 after castingprovided that the minimum cube strength

reaches 18MPa. Once extensions of tendonsare found satisfactory, all support workscould be removed. Thus the stagingmaterials, support works and coffers could berecuperated immediately after, therebysignificantly reducing the standing time ofthose materials.

This method proves to be environmentalfriendly through a minimised use of timber,shutter boards, equipments and overallconcrete and steel.

ConclusionPost-tensioning provides an alternative toconstruction works that would otherwise beimpractical due to various factors such as timeconstraints, site conditions and architecturalrequirements. This technology has been widelyused for high rise buildings, bridges, parkingstructures, stadiums, etc. There is a wide range ofpossibilities where this method can be applied.Post-tensioning is not a new concept, thoughnot common in the local construction industry.With the various advantages it can offer, post-tensioning could be a prospective tool for futureconstructions in Mauritius.


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1. Introduction

In March 2011 the Procurement Policy Office(PPO) issued a second edition of its StandardBidding Documents (SBD) for large and complexworks [1]. For such works, this new edition will bethe only version acceptable for procurementexercises launched from October 2011onwards,allowing for a transition period till then for bidexercises already initiated using the previousversion of the SBD. The latest version of the SBDincludes the FIDIC 1999 Conditions of Contract forConstruction [2], meant for the procurement ofbuilding and engineering works designed by theEmployer. It is indeed a welcome move that thePPO has at last endorsed, in the wake of this newSBD, the FIDIC 1999 Conditions of Contract forConstruction.

2. Use of FIDIC 1999 Conditions of Contract forConstruction

According to the PPO the new SBD is intended forall works above Rs 400 million, or for complexworks irrespective of the contract amount,following prequalification. However, the PPO hasindicated that it will accept use of this documentfor lesser value works if the Employer considers itmore appropriate to use the FIDIC 1999Conditions for such works. With the advent of thisnew SBD and PPO’s declared flexibility regardinguse of the associated FIDIC Conditions, it isexpected that the FIDIC 1999 Conditions ofContract will be adopted increasingly for localconstruction works. It is thus imperative, foreffective contract administration, thatconstruction industry professionals using theFIDIC 1999 Conditions become fully conversantwith all its provisions and the underlying

philosophy.

3. Prevalence of FIDIC Conditions of Contract

Unfortunately the abovementioned FIDIC 1999Conditions are still relatively unknown inMauritius, even though they have been inexistence for more than a decade. Although suchConditions of Contract have been adopted locallyon a few recent projects, they have yet to gain

popular acceptance. On the other hand the 4th

Edition (1987) of the FIDIC Conditions of Contractfor Works of Civil Engineering Construction [3],which was reprinted in 1988 and again in 1992with certain editorial amendments, has beenwidely used over the past two decades. The 1987FIDIC Conditions are thus better known in thelocal construction industry. This paper willhighlight some of the main features thatdistinguish the FIDIC 1999 Conditions from theprevious 4th Edition of the FIDIC Conditions. The4th Edition FIDIC Conditions and the FIDIC 1999Conditions of Contract for Construction will bereferred to herein as the Red Book and New RedBook respectively.

4. Shifting from the Red Book to the New RedBook

There are excellent published papers [4] andbooks on the FIDIC 1999 Conditions of Contract.The interested reader would be well advised torefer to such publications for a detailed analysis ofthe New Red Book and for guidance on its use.Nevertheless the issues discussed here wouldprovide a brief introduction to those who maynot be familiar with the New Red Book provisions.In particular, those who are considering a shiftfrom the Red Book to the New Red Book should

Salient Features of the FIDIC 1999Conditions of Contract forConstruction

Ram Bahadoor, MBA CEng FICE FCIWEM FCIArb [email protected]

Ram Bahadoor is a Past President of the Institution of Engineers Mauritius. He is presently the Country Representative forMauritius of the Institution of Civil Engineers of UK, and is a member of the Managing Committee of the Chartered Institute ofArbitrators (Mauritius Branch). He is an Accredited Mediator, Adjudicator and Arbitrator specializing in construction disputes.


30

find the salient features discussed below to be ofsome interest.

5. Structure of the New Red Book

The Red Book was published as two separatelybound volumes, comprising a Part I - GeneralConditions, as well as a Part II - Conditions ofParticular Application with Guidelines for thepreparation of Part II Clauses. The New Red Book,on the other hand, consists of a single document.This document comprises three parts as follows:

1) General Conditions

2) Guidance for the Preparation of the ParticularConditions

3) Letter of Tender, Contract Agreement andDispute Adjudication Agreement

The 72 Clauses comprising the GeneralConditions of the Red Book have now beenreduced to 20 Clauses in the New Red Book,which makes it difficult to compare individualSub-Clauses. Some of the Sub-Clauses areidentical but have been rearranged withindifferent Clauses and are hence renumberedaccordingly. Sub-Clauses have also been addedwhich comprise new requirements altogether.Some of the Red Book Sub-Clauses have beenretained, but with minor changes in wording tomake their intended meaning clearer.

It is thus advisable to scrutinize carefully all theprovisions of the New Red Book rather thanattempting any direct comparison with thecorresponding provisions of the Red Book.Relying upon such a comparison could actuallybe dangerous for the unsuspecting drafter tryingto customize the Conditions for a specific project.One may indeed be tempted, when preparing theConditions of Particular Application for the NewRed Book and discovering provisions apparentlymissing in the General Conditions, to copy someof the provisions that were previously used forthe Part II Conditions of the Red Book. But itwould be unwise to do so, as many such apparentomissions have in fact been catered for in one orother of the renumbered and rearranged Sub-Clauses of the New Red Book.

6. Drafting Principles adopted by FIDIC

The FIDIC Committee responsible for drafting ofthe New Red Book sought to facilitate thepreparation of Conditions of Contract by ensuringthat the final document was both flexible and

user-friendly. Flexibility was introduced byanticipating alternative arrangements, and bystating in the General Conditions whichprovisions are subject to what is stated in theParticular Conditions. User-friendliness wasachieved by:

(a) Maximizing the General Conditions so as tominimize Particular Conditions

(b) Identifying one location for essentialcontract-specific data

(c) Making reference, in the relevant Sub-Clauseswhere further non-technical data is required,that this data is as stated in the Appendix toTender

When preparing the appropriate particularconditions for a specific project, it is advisable tokeep in mind the abovementioned principles andto refer to the guidance given in the New RedBook. Special care must be exercised, whenadding or amending any Sub-Clauses to suit theEmployer’s requirements. The allocation of risksreflected in the General Conditions must not beunduly distorted, for instance, by deleting certainSub-Clauses altogether or introducing newprovisions that may conflict with existing Sub-Clauses. Otherwise, contractual complicationsand disputes are likely to occur, which could inturn hamper successful completion of the project.

A careful study of each of the Sub-Clauses isobviously a must for anyone planning to use theNew Red Book for the first time. Prior experienceand familiarity with the Red Book is notnecessarily an advantage when it comes toshifting to the New Red Book.

Some of the important features of the New RedBook are discussed in the sections below.

7. Revised Definitions

A number of new or improved definitions aregiven in Sub-Clause 1.1 of the New Red Book. Afew noteworthy changes, as far as definitions areconcerned, include the following:

(a) The Defects Liability Period of the Red Bookhas now become the Defects NotificationPeriod in the New Red Book, which is a moreaccurate description since liability in its legalsense goes well beyond the usual one yearperiod for the remedying of defects.


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(b) The Defects Liability Certificate of the RedBook is now the Performance Certificate in theNew Red Book.

(c) A clear distinction is now made between theamount mentioned in the Letter ofAcceptance as the Accepted Contract Amount,and the Contract Price which is the amountinclusive of all adjustments in accordance withthe Contract.

(d) The term “Engineer’s Representative” is nolonger defined in the New Red Book, althoughthere is a reference under Sub-Clause 3.2 todeployment of a possible resident engineerwith delegated powers.

(e) The “Employer’s Personnel” is now defined andcomprises, besides the employees of theEmployer, the Engineer as well as anyassistants to whom powers may have beendelegated by the latter.

(f ) Cost is now defined as all expenditure“reasonably incurred ……” rather than“properly incurred …..” as in the Red Book.

8. Employer’s Financial Arrangements

Under Sub-Clause 2.4 of the New Red Book theContractor may request evidence from theEmployer that financial arrangements have beenmade or are being made to ensure that the latteris able to effect payments due under the Contract.The Employer’s failure to comply with this Sub-Clause entitles the Contractor to give 21 days’notice to suspend work or to reduce the rate ofwork under Sub-Clause 16.1. If he still does notreceive reasonable evidence within 42 days aftergiving such notice, the Contractor is entitled toterminate the Contract under Sub-Clause 16.2.

9. Change in the Role of the Engineer

There is a significant change as far as the role ofthe Engineer is concerned. Under the New RedBook, the Engineer is no longer required to beimpartial. He is deemed to act for the Employerunder Sub-Clause 3.1(a) whenever he carries outhis duties under the Contract, which is consistentwith him being deemed part of the Employer’sPersonnel. But the Engineer is neverthelessrequired to be fair whenever he is called upon tomake any determinations under Sub-Clause 3.5.

10. Time Limit for Employer to effect InterimPayments

The Employer is now required, under Sub-Clause14.7(b) of the New Red Book, to effect interimpayments within 56 days after the Engineerreceives the Contractor’s statement andsupporting documents. This is different from thecorresponding Red Book provision under Sub-Clause 60.10 where the payment is required to bemade within 28 days from the date of theEmployer’s receipt of the Engineer’s interimpayment certificate.

On account of this changed requirement in theNew Red Book, the Engineer cannot get awaylightly with any delay in certifying interimpayments. If he takes longer than the 28 daysallowed for him to issue a certificate, that delaywill correspondingly reduce the 28 days’ timelimit for the Employer to effect payment. If thishappens, the Employer would no doubt take theEngineer to task.

11. Contractor’s Claims

In the Red Book, extension of time could only beawarded under Sub-Clause 44 whereasentitlement to costs could arise under severaldistinct Sub-Clauses depending on the nature ofthe event giving rise to the claim. However, theNew Red Book provisions are different in thatSub-Clause 20.1 sets out a single claimsprocedure, for the Contractor’s extension of timeand additional payment claims.

If he intends to pursue such claims, theContractor is required to give notice to theEngineer as soon as practicable and not later than28 days after he became aware, or should havebecome aware, of the event or circumstance. If hefails to comply with this notice requirement, theContractor loses his entitlement to any extensionof time or additional payment, and the Employeris discharged from all liability in connection withthe claim. This onerous notice requirement willresult in the Contractor submitting notices at theslightest opportunity, lest he loses hisentitlement, even though he may subsequentlydecide not to pursue some of the claims.

Sub-Clause 20.1 also sets time limits for theContractor to submit particulars of his claim. TheEngineer is given a deadline as well to respondthereafter with his approval or disapproval of


32

the claim, prior to make a determination underSub-Clause 3.5.

12. Dispute Adjudication Board

As a consequence of the Engineer’s requirementto act for the Employer, the provision for theEngineer’s Decision under Sub-Clause 67.1 of theRed Book has been removed in the New RedBook. In lieu of the reference to the Engineer for adecision, the New Red Book provides under Sub-Clauses 20.2, 20.3 and 20.4 for disputes arisingbetween the parties to the Contract to beadjudicated by a Dispute Adjudication Board(DAB). This DAB mechanism for dispute resolutionis a major innovation of the New Red Book.

The DAB may comprise either a sole member, forsmall to medium sized contracts, or threemembers for larger or more complex contracts.For a three member DAB, each party nominatesone member for the approval of the other party.The parties then consult both these members andagree upon a third member to act as chairman ofthe DAB. The DAB members obviously need to besuitably qualified and experienced. They alsoneed to be totally independent of the parties, inorder to fulfill satisfactorily their role in theresolution of disputes arising at any stage of theproject. Such a DAB arrangement addresses themajor contention that the Engineer’s decision inthe Red Book required the latter to be judge andparty, since he was called upon to review his owndeterminations whenever the Contractorexpressed dissatisfaction.

13. Employer’s Claims

The New Red Book contains provisions underSub-Clause 2.5 which the Employer must complywith, if he has any claim against the Contractor,before he is entitled to make any deductions froman amount certified in a Payment Certificate.However, the requirements are less stringent thanthe corresponding ones for Contractor’s claimsunder Sub-Clause 20.1. The Employer, or theEngineer on his behalf, is required to give noticeof the claim as soon as practicable to theContractor, and to then submit particulars ofclaim. The Engineer thereafter makes adetermination of the claim under Sub-Clause 3.5.The Employer’s claims could involve eitherpayment from the Contractor, or an extension ofthe Defects Notification Period.

14. Conclusions

The adoption by the PPO of the FIDIC 1999Conditions of Contract for Construction, whichwas long overdue, constitutes a majordevelopment that should benefit the Mauritianconstruction industry as a whole. The New RedBook undoubtedly contains many innovations,some of which have been specifically introducedto address serious inherent shortcomings of theRed Book. It certainly provides for a morebalanced allocation of risks between the partiesto the contract, and offers a better mechanism fordispute resolution.

Provided its general conditions are notadulterated to such an extent that the riskallocation is grossly distorted, there is no reasonwhy the New Red Book cannot be successfullyused in Mauritius. However, the parties to theContract and construction industry stakeholdersin general must acknowledge and adhere to theunderlying principles embodied in the New RedBook provisions. Unless they do so, when draftingproject specific conditions of particularapplication, the New Red Book innovations wouldserve no purpose. The shift to the FIDIC 1999Conditions of Contract for Construction wouldthen become a totally futile exercise.

References

1. Standard Bidding Documents for Procurement ofLarge or Complex Works, With User’s Guide (2ndEdition, 2011), Procurement Policy Office of Mauritius(Document available at htpp://ppo.gov.mu).

2. Conditions of Contract for Construction, for Buildingand Engineering Works designed by the Employer(First Edition, 1999), FIDIC, Switzerland.

3. Conditions of Contract for Works of Civil EngineeringConstruction, (Fourth Edition, 1987 reprinted in 1988and 1992 with amendments), FIDIC, Switzerland.

4. See the Resources Section at www1.fidic.org for a few articles.

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The Dispute Adjudication Board ApproachDispute Adjudication Board (DAB) is a relativelynew dispute resolution method introduced toresolve construction disputes. It is a permanentand independent body whose function is to assistcontracting parties in resolving any disputeappearing during contract performance.

In general, the DAB is set up at the outset of thecontract before any dispute has arisen. In order tobe able to assist the parties effectively andwithout delay, the DAB is at their disposal for theduration of the contract. It constitutes an organ ofthe project itself.

DAB: Main FeaturesDAB assistance usually consists of two main steps:

(a) Informal assistance on questions of principle;the parties jointly inform the DAB which thenrenders a preliminary opinion.

(b) Formal assistance in case of a referral: afterhaving received a short position paper by eachparty and a hearing with the parties, the DABhands out a decision in the form of a writtenreport.

The provision of informal assistance in the form ofadvisory opinions by the DAB is at the heart of itsintervention in terms of efficiency. Advisory

opinions are an informal method of advising theparties on resolving potential disputes. Before issues crystallise into disputes,disagreements between the parties will generallyfind their solutions thanks to informal assistance.The DAB will provide advisory opinions whenrequested jointly by the parties. Frequently suchopinions deal with questions of principle, forinstance, interpretation of a specific provision ofthe contract. Such opinions may be given orallyor in writing.

Dispute Adjudication Board: a Creature ofContractA dispute board is a creature of contract. Virtually allis derived from standard contracts which providefor DAB in specialised fields such as constructionand engineering contracts. Most of such contractswill nowadays contain a dispute resolution clauseof some kind and virtually will provide for DAB.

The parties establish and empower a DAB withjurisdiction to hear and advise on the resolution ofdisputes. DAB panels may consist of a singlemember or three members. A dispute board of oneperson can be utilized. Both the World Bank andthe FIDIC family of contracts encourage one-personboards for small and medium size contracts. Apanel of three is not usual but his composition isnot mandatory.

Changing Trend in Dispute Resolution inthe Construction Industry: Dispute Adjudication Boards

Kailash Dabeesingh, Civil Eng. MSc Arch. MSc Con. Law,FRICS, (Chartered Quantity Surveyor) FCIArb, (Chartered Arbitrator)

[email protected]

Mr Dabeesingh worked in the UK with leading construction companies and served in various capabilities in a number of

prestigious projects. Besides being a Civil Engineer, he has gained a Master degree in Architecture at the University College

London (UCL) and a Master degree in Construction Law and Arbitration at Leeds Metropolitan University. He also studied

international arbitration at Keble College, University of Oxford.

Mr Dabeesingh is the only Chartered Arbitrator in Mauritius. He has been involved in a number of arbitrations both in

Mauritius and overseas. He also serves as an adjudicator on Dispute Adjudication Boards to help the construction industry in

the resolution of disputes and conflict avoidance.

Mr Dabeesingh is actively involved in promoting alternative dispute resolution in Mauritius and is a frequent speaker at both

national and international conferences.


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DAB- Real Time Dispute ResolutionThe abiding goal of establishing a DAB is that it has‘real time’ value. By real time dispute resolution, it ismeant that there is a defined mechanism forresolving disputes during the currency of theproject. The idea behind a standing DAB is that itmay be called upon early in the evolution of anydispute which cannot be resolved by the partiesand asked to publish decisions on how the mattersin issue be settled. For maximum effectiveness, theDAB should become involved as soon as it becomesclear that a bona fide dispute disagreement exists.

Determination of the Dispute AdjudicationBoardThe DAB operates within the framework of thecontract. The usual procedure for disputeresolution consists of a prompt referral of thedispute. The DAB has a mandated shorttimeframe within which it is to make a bindingdecision. These are typically stated in days.

The decision of the DAB is binding but not final,that is, parties are free to accept or reject thedecision but are compelled to comply with itsterms immediately. Experience shows that thisapproach makes it possible to take decisionsmore rapidly and to accelerate the resolution ofdisputes.

DAB- Growing PopularityThe DAB is a dynamic and proactive method ofdispute resolution. It is currently known to be inoperation for the construction of the upgradingof Dr A G Jeetoo Hospital and the construction ofthe New Airport of Mauritius.

The contracting parties of the construction of theNew Security Prison at Melrose have alsoexpressed considerable interest in adopting thisapproach for dispute resolution. DABs areundoubtedly set to grow in popularity andfrequency of use in Mauritius.

Skills of the Dispute Adjudication Boardmember When appointing a DAB member, the contractingparties should recognise that completeobjectivity, impartiality and freedom from conflictof interest for the duration of the contract arenecessary attributes.

It is also important that the prospective DAB

member has the appropriate constructionexperience, including experience of claims anddispute resolution, knowledge of contractinterpretation and knowledge of disputeresolution procedures. Good ‘people skills’,independence, understanding as to the type ofproject are also important criteria. In essence, theDAB member should be a highly trained andrigorously professional.

BenefitsMany advantages can be discerned byincorporating the services of a DAB into acontract.

(a) Dispute avoidance : The single biggestadvantage is that the procedure gives focus anddirections in the resolution of disputes andconflict management.(b) Better decisions: The detailedknowledge acquired by the dispute resolver ofthe project enables him to reach a moreinformed decision within the prescribed time.

The parties to the conflict will be able to take fulladvantage of the knowledge of the project teamsand relevant team members in achieving aresolution of disputes as they arise under thecontract.(c) Less disruption: Rapid resolution ofdisputes enables parties to become lessadversarial. It helps maintaining a good workingrelationship. It offers an opportunity to confrontissues as the project unfolds. The resolution ofdisputes with the project teams as the projectproceeds avoids resources to be locked incontractual disputes on completed disputes. Itsaves senior management time and cost.

Remuneration: The DAB member is paid on thebasis that he is part of the entire project team andthat he will be on the project from the inceptionuntil its conclusion. The parties share all costsequally.

ConclusionConstruction projects in Mauritius need a modernand dynamic framework for dispute resolutionand conflict avoidance. The setting up of DABscan be a useful tool in the dispute resolutionarmoury for preventing and resolving disputes.


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Preamble

Construction is and will remain a very buoyantactivity in Mauritius as the country steers itself inmore ambitious building and infrastructureprojects. The ongoing projects such as the NewSSR International Airport at Plaisance, MCBBuilding at Trianon, Terre Rouge-Verdun Highway,Plaine Wilhems Sewerage Project, BagatelleShopping Mall etc have brought new dimensionsto construction techniques bringing in its wakemany new hazards at work. There is therefore, anurgent need for all stakeholders at work to keepabreast of the safety and health measures to beimplemented in line with an Occupational Safetyand Health Management System. Proper riskassessment for all operations which may presentdanger to persons at work and the public at largeneeds to be carried out by competent personswithin the company or outsourced to safetyprofessionals operating on consultancy basis.

The accident statistics are reminders of what cango wrong on construction sites; last year therewere nine fatalities in the construction sectorwithin Mauritius. Accidents on construction sitesare spectacular sometimes with dramaticconsequences – last year we saw a few scaffoldingcollapses which has prompted Government tocome up with the new Occupational Safety andHealth (Scaffold) Regulations 2011.

A new phenomenon has cropped up in theconstruction scene in Mauritius over the lastdecade with the presence of thousands ofexpatriate employees having different workculture and language barrier working alongsidetheir Mauritian counterparts. It becomes a realchallenge for the safety professionals on site totry and harmonise a safe system at work involvingall the stakeholders.

Evolution of Safety and Health Legislation

The first major safety and health legislation wasthe Health, Safety & Welfare Regulationspromulgated under the Labour Act in 1980 (GN358 of 1980). Government decided to structure aFactory Inspectorate at the Ministry of Labourand Industrial Relations to enforce this legislationas the number of accidents was alarming back inthe eighties.

It became obvious that GN 358/1980 was notgiving the required results as there were manyloopholes. In 1983, I was recruited to head theFactory Inspectorate and Government took thedecision to draft the Occupational Safety, Healthand Welfare Act. The Occupational Safety andHealth Act (OSHWA of 1988) was promulgated on01 May 1989. There was a major shift in the mainphilosophy of the Act – this was the first time thatan Act will bind the state and there were specificprovisions for all stakeholders at any place ofwork (employers, employees, designers,manufacturers of plant and equipment, owners ofbuildings etc). The onus was more on employersto auto-regulate safety and health practices attheir place of work instead of relying on theenforcement role of Government inspectors todetermine weaknesses in safety and healthpractice at the workplace. A new group ofprofessionals known as Registered Safety Officersbecame reality and thanks to them there hasbeen a major improvement in safety and healthstandards at the workplace, this preserving thehealth of the society at large.

OSHWA 1988 made way for the most recentOccupational Safety and Health Act 2005 (OSHA2005). With the introduction of OSHA 2005, theGN358/1988 and OSHWA 1988 were repealedexcept for part XIX of GN 358/1988 which dealt

Safety and Health in the Construction Industry

Claude Wong So, OSK FIEM [email protected]

Claude Wong So OSK is a Fellow of the Institution of Engineers Mauritius and Fellow of the

Institution of Occupational Safety and Health Management. He has wide experience as Project

Manager of many prestigious construction projects in Mauritius. He is a Civil Engineer, an occupational hygienist and a safety

consultant who regularly participates in seminars on Safety and Health with prime objectives to create more awareness, to

promote, stimulate and encourage high standards of safety and health at all workplace.


38

with the regulations for building and excavationworks in the construction industry.

Over the last two years, there were manyscaffolding accidents in the constructionIndustry; the most recent ones being at Ebeneand Pailles. This prompted Government topromulgate the Occupational Safety and Health(Scaffold) Regulations 2011 known as GN64/2011which came into effect on 28 April 2011. This nowforms the basis and norms to be observed in theerection, maintenance and dismantling of anyscaffolding system.

The Ministry of Labour and Industrial Relationscontinues to assist employers on constructionsites with the publication of regular guidelinessuch as Risk Assessment Guidelines etc.

International Best Practice of Safety andHealth in the Construction Industry

Most countries have come up with new conciseand strict safety legislations moving the legalduties to enforce the safety provisions onto theemployers and other stakeholders at the place ofwork. This places greater emphasis on everybodyat work to adopt a better safety and healthculture.

Companies now employ competent persons tomanage the safety and health policies enunciatedin a well defined and structured OccupationalSafety and Health Management System (OSHMS).There should be a right balance between therequirements of legislative provisions and theneed to impart practical advice on the safeimplementation of such legal requirements.Safety professionals lean a lot on Codes ofPractice or best practices known in othercountries.

In Mauritius, there is greater awareness of thedangers on construction sites and all thestakeholders are given regular induction coursesto keep them abreast of the latest technologies orhazards at work. Training thus becomesparamount in this effort towards better safety atwork. OSHA 2005 places duties andresponsibilities on employers, employees, self-employed persons, safety and health officers,registered engineers, registered machineryand/or boiler inspectors, manufacturers, suppliersand installers of plant and equipment etc. and ifeverybody takes his responsibility seriously, thenumber of accidents in the construction industrywill decrease further.

Most companies now adopt the OccupationalSafety and Health Management System in linewith OSHAS 18001 illustrated in figure 1.

Safety and Health management is not differentfrom other form of management. Accountabilityand responsibility of line managers andemployees is primordial and the decision makingprocess is a very important feature of themanagement process.

Management is concerned with people at alllevels of the organisation and human behaviour,in particular human personal factors such asattitude, perception, motivation, personality,learning and training, and communication bringsthese various behavioural factors together.Themanagement of safety and health is alsoconcerned with organisational structures, theclimate for change and individual rules within theorganisation.

In practice, all companies are advised toimplement a proper OSHMS at their workplace.Such OSHMS must incorporate the followingimportant aspects: -

(a) Be chaired by a very senior member ofmanagement who can take decisions onsafety and health matters and be composedof equal number of management andemployees representatives.

(b) The company written Safety and Health (S &H) Policy;

(c) Procedures for S & H monitoring andperformance measurement;

(d) Clear identification of the objectives andstandards which must be measurable and

Figure 1 OHSAS 18001 - Occupational Health and Safety Management System


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achievable by the persons concerned;

(e) A system for improving knowledge, attitudesand motivation and or increasing individualawareness of S & H issues, responsibilities andaccountabilities;

(f ) Procedures for eliminating potential hazardsfrom plant, machinery, substances andworking practices through risk assessment,the design and operation of safe systems ofwork and other forms of hazard control;

(g) Measures taken by management to ensurelegal compliance;

(h) Management structure through competent S& H professionals.

The OSHMS is a live document and needs to bereviewed and updated at regular intervals. It willcome a time in Mauritius where OSHMS willbecome accepted as a management tool andhopefully this will contribute to a better workingenvironment and a more healthy and stress freesociety.

Risk Assessment in Construction Industry

The construction industry remains a sectorwhere accidents do occur with consequenceswhich may be dramatic at times. It is therefore amandatory requirement that safety and healthissues are given priority attention by personsconversant and competent in risk assessmentand aware of the legal provisions in force inMauritius.

Planning for hazard identification, riskassessment and risk control under OHSAS18001:1999 should be a priority of constructionsite engineers and their safety consultants. Asimple way of evaluating risk is detailed below:

(i) Know the sequences of the constructionprocess

To be able to carry out a proper risk assessmentanalysis, we have to know all the sequences ofthe construction process and go throughavailable records of past performance of thecompany under similar working conditions. Ifsuch information is not available, the riskassessment will have to start from scratch, allhazards identified and control of remedialmeasures taken to eliminate or minimize therisks at work.

(ii) Analyse operations in each sequence

Each sequence of work comprises of severaloperations; each operation needs to beanalysed.

(iii)Identify and evaluate hazards in eachoperation and the probability of each hazardgiving rise to an accident or dangerousoccurrence.

(iv)Classify risk by assigning a risk levelestimator

(v) Propose control measures to keep the risk toas low as possible.

(vi)Ensure that proposed control measures haveeffectively been carried out on site prior tostart of the risky operations.

Role of Engineers under OSHA 2005

Engineers in all fields of engineering play a majorrole in maintaining safety standards onconstruction sites; they are the mastermind ofthe whole construction cycle and have to ensurethat work is planned and performed in the safestmanner.

OSHA 2005 prescribes specific areas whereengineers with other competency are broughton site to assist the project team.

A registered Professional Engineer preferably inthe Mechanical or Electrical fields shall beappointed in charge of all machinery and plantwhere the total installed power exceeds 750kW.

Certain machinery and equipment such asmobile or tower cranes, hoists and lifts, airreceivers, escalators, boilers etc are widely usedon construction sites. Under specific sections ofOSHA 2005, these machinery and equipmentneed to be examined by a Registered MachineryInspector or Registered Boiler Inspector as thecase may be. These inspectors are dulyrecognised by the Ministry of Labour andIndustrial Relations and are therefore licensed tocarry out the mandatory examinations atintervals prescribed in OSHA 2005. RegisteredMachinery Inspectors must examine cranes andlifting machines (S.51), vehicles lifts (S.52), hoistsand lifts (S.53), escalators (S.54), air receivers(S.59), refrigeration plants (S.61).


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Registered Boiler Inspectors must examine steam boilers (S.57), steam receivers and steam containers(S.58). All certificates of examination must be forwarded to the Ministry of Labour and IndustrialRelations by the employer within 28 days from date of examination.

Quick Evaluation of Performance of Safety at Work

Companies should institute a proper Safety and Health Committee on each major site. The SafetyCommittee must meet regularly and all accidents/incidents/dangerous occurrences must be discussedunder a No Blame Culture; causes behind the accident/incident/dangerous occurrence identified withremedial actions proposed to prevent similar recurrence in future. I had the occasions to work as SafetyConsultant on some major constructions sites in Mauritius (Centrale Thermique de Belle Vue (DukeEngineering), Plaines Wilhems Main Sewer Line (Jan de Nul) and New SSR International Airport (CSCECand Louis Berger Group) and a common feature on all these three major construction sites was thepublic display of an Accident and Incident Statistics Board on which the track report of safetyperformance of the company is reproduced on a monthly basis.

The statistics for the ongoing SSR International Airport project are reproduced below:

Note: Serious accident = more than three (3) days off work from industrial injury

LTI Frequency Rate = No. of Accidents x 100,000/Total No. of manhours worked

At a glance, the readers can immediately assess the safety performance on this site of work. I encourageall safety consultants to adopt this approach to keep track of the safety performance of their company.


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Occupational, Safety and Health (Scaffold)Regulations 2011

Scaffolding remains one of the best documentedsector in the safety field; yet many accidentsoccur from poor understanding and applicationof the techniques involved in safe erection,maintenance and dismantling of scaffoldingespecially in high rise construction.

The main provisions of the OSH (Scaffold)Regulations 2011 are briefly summarizedbelow.

REG 3- Erection or dismantling of scaffold > 6m,

must be carried out by a competent person- Erection or dismantling of scaffold < 6m,

Permanent Secretary may direct employer toemploy competent person if risk of accidentis high.

- Employer to notify permanent secretary ofemployment of competent person.

REG 4- Duty of employer before use of scaffolding - Check for secure and effective bracing to

ensure stability in all directions- Check for secure anchorages vertically and

horizontally to structure on which work isbeing performed exception for selfsupporting scaffold

- Inspection by competent person at regularintervals and after bad weather

- Provide suitable and appropriate PPE toemployees involved in erection, alteration,inspection, use, maintenance or dismantlingof any scaffold.

- Adequate and appropriate information,instruction and training to all employeesinvolved in scaffolding work.

REG 5- Mandatory requirements in any scaffold- Method of support of every plank – minium 3

supports. Protection >150mm V250mm - Every board to be securely fastened to

prevent its displacement - Boarding of every platform to prevent tools

and materials from falling through minimumheight

- Working platform > 2m from floor level, toprovide sturdy guardrails 1.2m high on allsides where employees may fall.

- Distance between platform and face ofstructure not to exceed 70mm; can beincreased to 300mm if employees have to sitwhiles working (rendering on walls instanding position)

- Every working platform to be kept clean , freefrom waste, projecting nails etc andmaintained in non-slippery condition.

- Proper guardrails, fencing or enclosure to anyopenings or open side of any scaffold wherepersons may fall.

- Protection above any entrance orpassageway or above any place wherepersons work on regularly pass.

REG 6 In addition to Regulation 5, employer to ensure - That scaffold is of good construction, sound

material, adequate strength and free fromdefects.

- That the materials used and the design ofscaffolds are in accordance with approvedstandards, if any or manufacturer’sspecifications.

REG 7Duties of Manufacturer or Supplier of any

scaffold- Ensure that the scaffold or materials used for

scaffolds are in accordance with approvedstandards if any

- Provide adequate information by way ofcertificate, manual, pamphlet or otherwise,about the use for which it has been designedand tested.

REG 8- Convenient and safe access to every scaffold

platform- Safe use of ladders as means of access

We illustrate below a few examples of goodpractice in scaffolding at the New SSRInternational Airport.


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Conclusion

Safety and Health management on anyconstruction site should be the concerned of allstakeholders. Risk assessment should be giventop priority by the site management team.

Compliance with existing safety and healthlegislation and best safety practice inconstruction techniques should be closelymonitored.

Training of employees is a paramount toobservance of safe practice on site.

Accident/Incident/Dangerous Occurrencestatistics should be displayed on public board toshow performance of the company.

References

Occupational Safety and Health Act, OSHA 2005Construction Industry Training Board –Construction Site Safety Notes

Acknowledgement

Airport Terminal Operation Limited, ATOLLouis Berger Group, LBGChina State Construction EngineeringCorporation, CSCEC


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Society values human life and endeavors to saveit at all times in any field of human activities.Construction field is one of the most hazardousfields of activity wherein lots of fatal as well asaccidents with serious injuries occur.Surprisingly most of these accidents would nothave occurred had there been timely andadequate safety measures taken.

Blame is generally put on a Builder/Contractorbecause the accident occurs on the sites ofconstruction in their possession irrespective ofwhether they are wholly responsible for the faultcausing such accidents. The teams ofConsultants at times are not contributing forensuring that safety measures taken areadequate and are being constantly monitoredby a Health and Safety Officer. Workers at timesare also not informed/trained to know thesituation likely to cause accidents, to takeprecautions and/or to refuse to work in suchsituations if their employers do not takeadequate measures in advance.

The so called fast track jobs with constraints ofprocurement, lack of skilled manpower &technicians rushing to the completion of itemsof work lead to accidents because neitheradequate time is allowed for nor proper safetymeasures are taken. The team of the Builders &Consultants should meet at the start of theproject to define their roles and the actions to beenforced by each of them should be listed foreach item of work likely to cause accidents. Thecurrent situation is such that at very few site

meetings of the building & civil engineeringprojects such roles are either planned and/oracted upon.

This paper provides a list of the main safetymeasures, for the construction of structural/civilengineering works, based on experience gainedby the author in such works. The measures forthe health including administrative measuressuch as wearing helmets, safety shoes & glovesetc are not dealt with here.

I. Foundation

Excavation in Building & Civil EngineeringWorks Labour Law 1991 Section 94 & Road Act 1966part 1 sec 16 & 17, Part II Sec 45 deal with Barrier,Fencing, Warning tapes, Warning lights/signs,Traffic signs/controls etc. Also, Occupation Safety& Health Act (ASHO) 2005 deals in detail with themeasures to reduce accidents to zero level.The following deals with shoring and strutting ofthe sides of excavations to reduce accidents.

A. Excavation in depth not exceeding 1.5m to2.0m

The safety measures to excavation particularly of1.5m to 2.0m depth are not attended and as suchcauses accidents with injuries at times seriousones. Most of the terrains encountered inMauritius have varying depth of top soil which ismade of unstable material such as clay, clayey slitand loose sand. Water penetration due to rain,water leakage from existing services & dumpingof excavated material on the edge of the

Safety in the Construction Industry:Mauritian Perspective

H V Jadav, Consulting Civil/Structural Engineer SJPCE [email protected]


45

excavated face cause collapse of the sides of theexcavation.

Engineers do specify strutting of the sides ofexcavation in such soils. However, most of thetimes sides of excavation are left unattendedeven with minimal strutting by the builders.When enforced by the team of consultants i.e. byengineer reporting, by architects warning, byproject manager stopping works, then Clients on

advice of the consultants should withholdpayment to the time until the builder respectspecs and/or instructions given.

The sketch No 1 attached shows the typicalshoring and strutting for excavation of trenchesnot exceeding 2.0m from the ground for thedepth of the unstable topsoil strata at the top.

sketch No 1


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B. Excavation in depthexceeding 2.0m up to 3.2mFor depth up to 3.2m for theground, for excavation invery stiff soils, decomposedrock below the loose top soildepth above not exceeding1.0m, stepped excavation is aclear choice. Measuresshown on sketch No 2 forsuch stratas are normallyfound adequate afterinspection of the soil stratasby the design Engineer.

sketch No 2

sketch No 3

Excavation for depths up to3.0m depth from groundlevel for basements ofbuildings and massexcavations for civilengineering construction etcin loose sandy soil.

It is preferable to use steppedexcavation but with the facescompletely lined in corrugatedmetal sheets with scaffoldtubes as walers & struts.Ensuring the lining & struttingat the top is completed beforeexcavating the next steppeddepth below. The sizes of thevarious depths & the width ofthe edges depend upon thetype and the nature of the sandstratas. Sketch No 3. showsdetail of strutting for loosesandy soil. It may beadvantagous to wet thesurface overnight before eachsteps of the excavation arecarried.


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C. Excavation for New Constructionadjacent/abutting the existing foundation ofadjacent Building/Construction

For the commercial zones of the Cities, theconstruction is permitted extend up to its plotboundary. Therefore many times newconstruction including its foundation is builtagainst the adjacent construction including itsfoundation.

These adjacent construction needs to besupported by

(a) Underpinning works in stages to itsfoundation and

(b) Shoring of its walls at the boundary line or inthe vicinity of it to avoid collapse of the wallscausing accidents, at times fatal on theadjacent site of the new construction.

It is the job of the contractor to ensure thatexcavation for foundation are not commenceduntil underpinning works to the existingfoundation & shoring of the existing walls arecompleted as detailed/designed or approved byhis Clients’ design engineers. And also he/sheshould seek inspections & written approvals ofthe Clients’ design engineers of theunderpinning & the shoring works to his/herapproved details.

Because lack of the above mentioned input

(a) by the contractor’s & Client’s designengineers and

(b) by the Municipal Authorities before an issueof a Land Use & Building Permit not asking forsuch input in the form of design & drawingsfrom Client’s design engineers, invariablyresults in accidents with serious injuries &deaths followed by long legal proceedings.

D. Excavation for Deep Foundation

For deep foundation for basements to retain theexcavated faces from falling, any one of thebelow mentioned measures are generallyemployed:

(a) Providing micro piles at close centres with ablancket of reinforced screen in between heldby inclined geo nails or drilled anchors, allunder the supervision of a ProfessionalEngineer with past experience of such works.

(b) The 600mm to 800mm thick reinforcedconcrete diaphragms walls to all four sides ofthe perimeter of the area of basements ofbuildings and for mass excavations for CivilEngineering Construction, are constructed bymechanically operated rectangular augers in1.5m to 2.5m lengths for their excavation i.e

long shaft with bucket attached to its end forexcavation as well as for grabbing/removingthe excavated material. Concreting of thediaphragm walls are carried out in bentoniteslurry to hold the excavated faces on foursides. The excavation to the main areacommences after the construction of thediaphragms walls on the perimeter under thesupervision of a Professional Engineer withpast experience of such works.

(c) Metal sheet pilling are driven into the groundon the perimeter before the commencementof excavation to the main area of basementworks for Buildings or retaining massexcavations for Civil EngineeringConstruction, all under the supervision of aProfessional Engineer

(d) Any other proven measure for deepexcavation where so acceptable by both asoil mechanic-expert as well as a foundationengineer of the consultants both experiencedin such works.

The following is a list of useful generalprecautions to be taken before and duringexcavations to stop accidents due to collapseof the sides of excavation.

(a) Cart away the excavated material by loadingthe truck standing at least 2.0m preferablymore away from the edge of the excavation.

(b) Don’t dump excavated material in the areaadjacent at least for a certain width(equal to0.67 times depth of top soil) from the sideexcavated face of excavation.

(c) Protect the excavation by dressing thesurface around it with a slopeto drainrainwater away from the excavation.

(d) Protect the face of excavation from the directrain by polyethene sheeting well lapped,placed and held in position.

(e) Ensure that water do not accumulate at thebottom of excavation by providing adequatesize &nos of sumps at the bottom of theexcavation at appropriate places andpumping out the water from these sumpsbefore the sides of the excavation getwet/soaked/unstable.

II. Scaffolding for Construction

Provisions made under the Mauritian Laws forOccupational Safety and Health Act 2005 (OSHA)and the recently enacted OSH (Scaffold)Regulations 2011 no. 1 to 16 came into operationin April 2005. Regulation No. 5 lays out themandatory requirement in any scaffold. Thefollowing deals with scaffold for multi storeybuildings and other related subjects.


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A. Work-scaffold on the façadeof the multi-storey buildings

Main causes of fatal & serious accidentsdue to faulty scaffolding on suchfaçades are

(a) The scaffold cage is not diagonallycross braced at intervals on its frontat its ends & on its intermediatelengths.

(b) The scaffold cage is not tied backadequately to the alreadyconstructed part of the structure ofthe Multi-Storey Building and/or tothe internal scaffold supportsbetween the floors below the lastfloor heights under construction.

When tied back to the scaffold supportsto the floor above under construction,the vertical scaffold tubes for the floorare required to be well held at its top &bottom and to be well cross braced atits mid height by horizontal bracing inboth directions.

(c) The tied back-scaffold to thefacade should be replaced by new tieback with well braced and anchored scaffoldbracing to the r.c structure of the walls, columns/ floor slab before removing the bracingmentioned in item (b) above.

SketchNo 4 shows the details for item (a) to (c)above.

(d) The platforms between the scaffolds andthe floor at hoists need to be adequatelysupported at one end to the hoist independentof bracing to the hoists and to the floor or toexisting construction at its other end, all wellbraced to the floor. The handrail to suchplatforms to be well tied to the alreadyconstructed structural members of the floorsabove & below. Regulation no. 5 of OSH 2011specifies gap between scaffold tower and thebuilding to avoid accidents.

(a) to (d) need to be checked by a ProfessionalBuilding/Safely Inspector together with theresponsible representative of the consultingteam before the façade scaffold & the hoist areallowed to be used for works and/or fortransfer/transport materials.

General Notes on Formworks to the concretefloor to avoid collapses

(a) The modern structures have flat slabs in areawithout beams and with columns far apart.The faulty formworks to such slabs will resultin collapse of the slab above if the formworksto such slab have vertical supports not wellheld at its bottom and or not bracedhorizontally in both directions at mid or onethird heights to stop failure of vertical propsfrom buckling, a major cause of collapse.Generally the formworks for such works is inmodular steel frames, bearers, beams &diagonal bracings to stop buckling of thevertical props.

(b) The formwork should not be overloaded bylocalized dumping of concrete and/orconstruction material as to cause collapse.

(c) Props to the formwork to a recently cast floorslab need not be removed unless therequired specified strength of the concrete isachieved. Tendency to remove formworkearlier than time specified so as to use it forthe floors above or for othersite is dangerous.

sketch No 4


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List of other items which generallyoverlooked but likely to cause accidents onthe construction site.

(a) Scaffold tubes projecting beyond the verticalplane of the scaffoldneed to be cut off andcapped so that such projections are harmlessfor the passers by.

(b) The steel anchors used to hold the formworksto r.c walls/columns should not projectbeyond the face of the formwork so as tocause accidents to people working around.Such anchors need to be removed and/ortheir projections cut when formworks isremoved.

(c) All reinforcement projecting above the floorslab should be cordoned off by warning signsand colored straps.

Building CollapsesWe hear major cases of fatal injuries in variouspart of the world including Mauritius due tocollapses of buildings.The main reasons for such occurrences are :

(a) Not carrying out timely remedial measures tothe deteriorated and/or unstable existingstructures and/or its foundations.

(b) Many depleted buildings are not demolishedin time after their useful life of 40 to 50 yearsand are left for years in such state withoutproper monitoring and timely actions withstructural repairs thereto.

(c) Inadequate/Improper design of foundations,mostly on poor e.g. expansive clays and/orloose filling. These occur either duringflooding of such areas and/or constructionnearby without adequate precautions.

(d) Inadequate/Improper designed formworks tofloors.

(e) Most collapses of the floor occurs becauseprops supporting the formwork are notbraced in both directions vertically atdistance to avoid buckling of props at timesthe bracing are nonexistent or scarcelyprovided.

(f ) Props are not adequate e.g. to carry to theloads of fresh concrete dumped in an area onthe formwork above which gives in resultingcollapse of the part of the floor.

(g) Premature removal of the props to theformwork before specified strength of theconcrete is achieved. This is done at times tosave costs on the formwork.

Conclusion

In this short article I have touched on few itemsonly. In the end I stress for

· Proper training of workers for taking allprecautions, for using appropriatetools/methods and inspections by the SafetyInspectors before the work commence.

· Safety Inspectors of the Governmentcarrying out periodic inspections and be givenpowers not to allow works to proceed if they findit unsafe.

· Suggest more involvement andparticipation by members of consulting team tocheck that builders/their safety inspectors areinspecting the works as per guidelines given inthe Health & Safety Regulations of theGovernment, ASHO 2005 and 2011.

· Officers visit & inspect site regularly andsubmit photographs weekly with list of theactions taken. A visit fortnightly round the sitebetween the consulting team & builder with hisHealth & Safety inspectors and GovernmentHealth & Safety inspectors with record ofminutes and actions will go a long-way to stoplikely accidents.

· Aim as stated in our ASHO 2005 and2011 is to achieve (a) zero accident to avoiddeaths and (b) people working can live theirretired life without loss of limbs.


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PreambleIt has been said that ‘Temples and bridges arethe most outstanding exhibits of mankind’. Onthe other hand, never earlier have so manynotable (long-span) bridges been built as duringthe change of the Millennium. The boom of greatbridges concerns long-span cable-supportedbridges, i.e. suspension bridges and cable-stayedbridges, particularly in China.

Keywords:Long-span cable-supported bridges, suspensionbridges, cable-stayed bridges, tensile strength ofcable wires, strong steel truss stiffening girders,novel streamlined steel box girders, earthquakeresistance, Ref.[1-2].

Introduction

This is a revised abridgement of articles [1 & 2]published in 1995 and 2001 respectively. Fulltext of the article is available for download onthe link provided or on the IEM website. Furtherto the development of suspension bridges withrespect to the growth of the main span, thematerials of towers are discussed, and themethods of assembling main cables and theincrease of tensile strength of the cable-wires areoutlined in article [1]. Also the two main typesintroduced for the deck structures are described,particularly after the collapse of the first TacomaBridge (in 1940): strong steel truss stiffeninggirders (in USA) and novel streamlined steel boxgirders (in Europe and Asia). The importance ofresistance against earthquakes is pointed out,particularly in view of the survival of the Akashi-Kaikyo Bridge in the notorious Kobe earthquakein 1995. Detailed drafts (longitudinal profiles,cross-sections on deck, front elevations on

towers) on long-span suspension bridges areincluded in article [2].

The term “span“ here means expressly the mainspan of a bridge = distance between c-c oftowers/pylons/piers/supports, definitely not thetotal length or overall length (= sum of spans) ofany multi-span bridge [3].

Long-span bridges

As appears in Table 1, which is a combination ofTables 1-2 of Ref.[3], there are in the world nearly30 bridges with a span longer than 1000 m.These all are cable-supported bridges(suspension bridges or cable-stayed bridges),most of which are in China. The record span ofsuspension bridges is near to the 2 km limit, andamong cable-stayed bridges the record span isan odd 1 km.

Among suspension bridges, No.1 is the mightyAkashi-Kaikyo Bridge, main span 1991 m,completed in 1998 (Fig.1 & 2). It is situated nearKobe, in Japan, along the Kobe-Naruto Route,between Honshu and Shikoku Islands. No.2 is theXihoumen Bridge (span 1650 m; completion year2009) in China, near Shanghai, and No.3 is theGreat Belt East Bridge in Denmark (1624 m;1998), some 100 km west of Copenhagen (Fig.3 &4).

Among suspension bridges for highway/railwaytraffic, No.1 is the Tsing Ma Bridge (1377 m; 1997)in Hong Kong, China. No.2 is the Minami Bisan-seto Bridge (1100 m; 1988) in Japan, along theKojima-Sakaide Route, between Honshu andShikoku Islands, some 100 km west of Kobe.

Among cable-stayed bridges, No.1 is the Russky

Long-span Cable-supported Bridges:General Review

Juhani VIROLA, Eur [email protected]


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Island Bridge (1104 m; 2012) in Vladivostok, Russia, No.2 the Sutong Bridge (1088 m; 2008) nearShanghai in China, and No.3 the Stonecutters Bridge (1018 m; 2009) in Hong Kong, also in China.

Table 1 The longest span cable supported bridges (span 1000 m), [3]

THE LONGEST-SPAN CABLE-SUPPORTED BRIDGES (span 1000 m) [3]

No. Bridge Span Location Year 1 Akashi-Kaikyo 1991 m Kobe-Naruto, Japan 1998 2 Xihoumen 1650 m Zhoushan, China 2009 3 Great Belt East 1624 m Korsor, Denmark 1998 4 Yi Sun-sin 1545 m Myodo-Gwangyang, Korea 2012 5 Runyang South 1490 m Zhenjiang, China 2005 6 Nanjing-4 1418 m Nanjing, China 2013 7 Humber 1410 m Kingston-upon-Hull, UK 1981 8 Jiangyin 1385 m Jiangsu, China 1999 9 Tsing Ma 1377 m Hong Kong, China 199710 Hardanger 1310 m Vallavik-Bu, Norway 201311 Verrazano-Narrows 1298 m New York, NY, USA 196412 Golden Gate 1280 m San Francisco, CA, USA 193713 Yangluo 1280 m Wuhan, China 200714 Höga Kusten 1210 m Kramfors, Sweden 199715 Aizhai 1176 m Hunan, China 201216 Mackinac 1158 m Mackinaw City, MI, USA 195717 Huangpu-1 1108 m Guangzhou, China 200818 Russky (c/s) 1104 m Vladivostok, Russia 201219 Minami Bisan-seto 1100 m Kojima-Sakaide, Japan 198820 Fatih Sultan Mehmet 1090 m Istanbul, Turkey 198821 Sutong (c/s) 1088 m Suzhou-Nantong, China 200822 Balinghe 1088 m Guanling, China 200923 Maanshan 2 x 1080 m Anhui, China 201024 Taizhou 2 x 1080 m Jiangsu, China 201025 Bosporus 1074 m Istanbul, Turkey 197326 George Washington 1067 m New York, NY, USA 193127 Kurushima-3 1030 m Onomichi-Imabari, Japan 199928 Kurushima-2 1020 m Onomichi-Imabari, Japan 199929 Stonecutters (c/s) 1018 m Hong Kong, China 200930 Ponte 25 de Abril 1013 m Lisbon, Portugal 196631 Forth 1006 m Edinburgh, UK 1964__________________________________________________________________NOTE:Those marked with (c/s) are cable-stayed bridges, others are suspension bridges.

Among cable-stayed bridges for highway/railway traffic, No.1 is the Tianxingzhou Bridge (504 m; 2009)in Wuhan, China, and No.2 is the Oresund Bridge (490 m; 2000) between Sweden and Denmark.

Among 1-tower cable-stayed bridges, No.1 is the Surgut Bridge in Russia (408 m; 2000), and No.2. is theHuangpu-2 Bridge (383 m; 2008) near Hong Kong, China. The projected Ulyanovsk Bridge in Russia wasplanned to have 1 tower and 2 adjacent spans of 407 m each, but the plan was changed for a shorter-span bridge type.

The longest-span bridge beyond cable-supported bridges is the Chaotianmen Bridge, a steel archbridge (span 552 m; 2008) in Chongqing, China. As appears from the Bridge Tables 1-7 in Ref.[3], steelarch and steel truss girder bridges may reach max. span about 500 m, concrete arch bridges 400 m,prestressed concrete girder and steel box and plate girder bridges some 300 m.


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Some proposed super long-span bridges of the future should be mentioned, too. For instance,suspension bridges like Qiongzhou in China (span something between 2000-2500 m); Messina in Italy(3300 m); Tsugaru in Japan (4000 m); Gibraltar Strait between Spain and Morocco (5000 m). Finally, agigantic cable-stayed bridge was proposed in the late 1980’s across the Gibraltar Strait with anenormous main span of 8400 m [4].

Figure 1: The Akashi-Kaikyo Bridge in Japan, greatestbridge ever built (span 1991 m). Photo taken towardssouth from the top of the Maiko Tower, near the northanchorage at Kobe side. - PHOTO: LEENA VIROLA,

Figure 2: The Akashi-Kaikyo Bridge, Leena Virolameasuring the 1/1-scale model of the Ø 1122 mm maincable. Photo taken near the Maiko Pavilion, at Kobeside. - PHOTO: JUHANI VIROLA

Figure 3: The Great Belt East Bridge in Denmark (span1624 m), under construction in 1997PHOTO: JUHANI VIROLA

Figure 4 : Korsor by night. The Great Belt suspensionbridge in the background. - PHOTO: LEENA VIROLA

Figure 5: The Tatara Bridge in Japan (span 890 m), oncethe world record cable-stayed bridge [3]. View from thetop of the Onomichi tower towards the tower at Imabariside. - PHOTO: JUHANI VIROLA


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Epilogue

Long-span bridges have interested us always,particularly great suspension bridges and alsocable-stayed bridges (Tatara). Hitherto, thefollowing long-span cable-supported bridges (inorder of main span) in Table 1: Akashi, Great Belt,Humber, Verrazano, Golden Gate, Höga Kusten,Fatih Sultan Mehmet, Bosporus, GeorgeWashington, Kurushima-3, Ponte 25 de Abril,Forth, and also some other long-span cable-supported bridges beyond the Table: Severn(span 988 m), Tatara (890 m), Transbay (2 x 704 m).

Excluding the 2 Istanbul suspension bridges(1090 m; 1074 m), in other cases we werepermitted to enter the top of the towers of thebridges mentioned above. The 3 suspensionbridges on the Kojima-Sakaide Route: MinamiBisan-seto (1100 m), Kita Bisan-seto (990 m) andShimotsui-seto (940 m) we crossed by train, andthe 2 suspension bridges on the Onomichi-Imabari Route: Kurushima-2 (1020 m) andKurushima-1 (600 m), we passed by ship, so thoseare not counted.

Through this paper and referenced documentswe hope to have enlightened the readers on longspan bridges around the world, as Mauritiusembarks on the venture of having one of its own:“The Dream Bridge”, as it is often quoted.

References:

[1] Juhani Virola: “Notable bridges in the world and inFinland” (original Finnish, 66 pic., a limited amount of reprintsavailable in English). Tierakennusmestari 1995:2, p. 85-104 &1995:3, p. 75-85.

[2] Juhani Virola: “Long-span cable-supported bridges” (18photos, 21 drafts). The Bridge & Structural Engineer 2001:2, p.1-44.

[3] Bridge Tables of the Helsinki University of Technology(TKK),www.tkk.fi/Units/Bridge/longspan.html

[4] Urs Meier: “Proposal for a carbon-fibre reinforcedcomposite bridge across the Strait of Gibraltar at itsnarrowest site”. Proceedings of the Institution of MechanicalEngineers, Vol.201, No.B2 (1987), p. 73-78.

Links:

Links:

* text of the full article "Long-span cable-supported bridges",http://koti.kontu.la/jvirola/casu.rtf

* illustration for select, 80 pic., in CD-Rom (size ca. 25 MB), ofthat full article, http://koti.kontu.la/jvirola/longspa5.ppt

*illustration texts of that 80-pic. CD-Rom,http://koti.kontu.la/jvirola/illust5.rtf

* text of a special article on the Akashi Bridge (span 1991 m),http://koti.kontu.la/jvirola/akakai.rtf

* concise CV about the author, http://koti.kontu.la/jvirola/cv-jv.rtf


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Introduction

This paper identifies some of the common defectsencountered in finishing works and proposesguidelines to avoid occurrence. We do not havethe pretention to cover each and every problemrelated to finishes neither do we believe that wehave solutions to all assignable causes of failures.

We have made recommendations for theselection of Materials used in masonry works andinvite users to refer to relevant Codes of practiceand entrust such works to skilled labour.

1. Finishing works in briefFinishing works in Building construction whichwill be the subject of this paper are: Renderingand Plastering external and internal walls,partitions, ceilings, and concrete surfaces,Screeding of both concrete floor and roofsurfaces.

Above works are carried out using mortarproducts which consist of cement, lime, sand,admixtures and water.

2. Rendering and Screeding The term ‘Rendering’ is used when one or multiplecoats of mortar are applied on either concreteblocks or concrete surfaces like Ceilings, Wallsboth internal and external.

The term ‘Plastering’ is sometimes misinterpretedand it is generally used to describe theapplication of a thin layer (3-5mm) of ‘Plaster’using either lime or gypsum (Plaster of Paris) asthe binding medium. Plastering is confined tointernal surfaces as the mortar used is notresistant to severe environment, rain, winds etc.We have sometimes recourse to ‘gypsum’ forplastering of ceilings and ‘gypsum boards’ forpartitioning.

Screeding is the finishing coat applied onconcrete surfaces like Floors and Roof tops.Applied to residential houses screeds mustadhere properly and durably to stratum, bestrong with a compressive strength preferably>10 N/mm².

In case of warehouses, industries i.e. industrialfloorings, besides the characteristics mentionedearlier on, compressive strength shall be greaterthan18N/ mm² coupled with high impactresistance and the finished product shall beresistant to vehicular traffic and aggressivespilling chemicals. Power floating is the best wayof finishing screeding and even for residentialhouses purposes small power floats are nowavailable on the market.

3. Description of defects and reasons foroccurrence

Blisters are bumps which wave and give riseto unleveled surfaces. They may not containcracks and arise as a result of errors inmaterials proportioning, excess water in themortar paste and also to floating startingwhilst mortar is still green.

Pop outs are isolated conical fragments thatbreak out of the surface leaving small holesand increase the porosity of the render. Anexcess of fine particles and high waterdemand allow air to be entrapped withpossible hair cracks.

Efflorescence is a white deposit thatdevelops on the surface and usually occurswhen salts, mainly calcium carbonate,migrate to the surface. Other conditions liketoo much water in the mortar and excessfloating of plastic paste are attributable tothis phenomenon.

Addressing Finishing problems in Building Construction

Karl Dulaurent, Technical Advisor, Lafarge (Mauritius) Cement [email protected]


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Cracks and fissures disfigure rendering andrender the finished surfaces porous andpermeable. These defects are a result of highwater dosage in the mortar combined withrapid loss of such water, low humidity, hightemperature, windy weather causing PlasticShrinkage cracks to develop.

De-bonding /Pull off of hardened mortarfrom the stratum, commonly known as‘Cloquage’ in the Mauritian jargon is quitecommon in Concrete Ceilings and Floor/RoofScreeds. Cloquage surfaces cannot berepaired and defective surfaces have to beremoved and replaced altogether. Causesare high suction of the stratum, the use ofinappropriate mortar and improperapplication methodology.

Crazing is a network of fine surface cracksand tends to form a chicken wire pattern. It isusually caused by the bad habit of castingdry cement to hasten drying and also due tolow humidity, high air temperature, hot sunand drying wind.

Dusting is development of fine powderymaterial that easily rubs off the surface ofhardened render .It is a result of a weak layercomposed of water, cement and fineparticles (laitance) which comes to thesurface. It is usually caused by water appliedduring finishing, the mortar being too wet,exposure to rainfall and insufficient curing.

The list of defects outlined above are notexhaustive and even such defects do notrepresent a hazard to the structure of thebuilding, the aesthetics greatly suffer, renderingsand plastering which shall primarily ensureprotection against dampness, porosity, waterinfiltration etc do not by virtue of these defectsfulfill their dedicated role.

4. Rendering and Finishing practice

Good rendering and finishing practice whenstrictly followed allows effective control andin certain cases elimination of defects inRendering and Screeding works.

The ‘thumb rule’ is to choose the correctmaterials which shall be gauged in correct

proportions, to select skilled peopleconversant with the applicationmethodology and the use of appropriatetools.

Specifications for materials are laid down inrelevant standards e.g. Portland cement toEN 197-1, Masonry cement to EN 413-1, Limeto EN 459-1, Water to EN 1008, and Sand toEN 13139 amongst others.

Furthermore, EN 13914 and BS 8000-9 areCodes of Practice for Render andWorkmanship respectively. There are alsonumerous publications giving usefulinformation regarding finishing works.

5. Some Hints on Materials andMethodology

Cement: The type of Cement commercializedin our Country is CEM 1 complying with EN197-1. This cement has a relatively high heatof hydration (300J) and a high Specificsurface (fineness) which may be causes forCracks and Cloquage and must be thereforebe used with utmost care.

Twenty years back we used to receive twotypes of Portland cement namely OrdinaryPortland Cement (OPC) and RapidHardening Portland Cement (RHPC) to BS 12and the user chose the OPC type for Masonryworks and fewer problems were thenreported.

There are strong indications that Cementsuppliers will introduce Masonry Cement toEN 413-1, and this product as its nameimplies shall be beneficial to Block/Stonelaying, Rendering and Screeding works.

Let us also recall that formerly the Sand usedin masonry was of Calcareous origin,rounded in shape, more workable, with ahigh water absorption value and slowevaporation rate. In such cases some suctionof gauged water from the mortar by thestratum was not so detrimental. Now thatCoral sand extraction has been prohibitedand substituted by Basalt Rock sand whichabsorbs less water followed by rapidevaporation and drying, defects are moreprone to occur.


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Another important material which wasincorporated in little quantities in Mortarmaking was Lime which imparts excellentworkability, good water retentivity, betterbonding to stratum and the probability ofless disorders resulting.

However, necessary precautions must betaken to avoid Efflorescence and lime bloom.

Admixtures: These exist in two versions,liquid and powder forms. We have all heardof ‘Plaze’ which is a liquid Plasticiser and isused to enhance Mortar Plasticity, to easeSpreading and prolong setting thus givingsufficient time to the masons to shape andfloat the plastic mortar.

Other admixtures like Water repellent areincorporated in mortars applied on externalworks to render finished surfacesimpervious. Polymer additives are used inScreeding mortar for better impactresistance and durability,

Application coats: render shall be applied insuccessive layers not exceeding 12mm; thefirst (pricking coat) or initial coat isroughened extensively in order to favour agood key for the following coats which areusually applied the following day. Thicklayers very often give rise to severe cracksand Cloquage.

Prime coat: on concrete surfaces it is stronglyrecommended to apply a thin coat (3-5mmthick) of bonding mortar before proceedingwith rendering and screeding.

Hardened render and plaster should not bevery strong and a compressive strength ofbetween 6N/mm² to 10N/mm² is sufficient.Generally best results are achieved when thehost Masonry is stronger than the appliedmortar

One shall refrain from proceeding withmasonry works at temperatures below 5⁰Cand greater than 35⁰C

Last but not least is curing which plays a vitalrole towards successful finishing due to thecapillary pores remaining saturated thusfavouring proper hydration of cement.Curing is carried out using either water

(cheapest solution) or curing compoundmostly water based. When water is usedcuring shall be maintained for a continuousperiod of 3-4 days.

Conclusion

Our objective in writing this paper is to draw theattention of Architects, Consulting Engineers,Project Managers /Quantity Surveyors, Building& Civil Engineering Contractors, and privateindividuals to recurrent problems of finishes. Wehope that users will follow the fewrecommendations we have outlined and webelieve that the curriculum of VocationalTraining Institutes shall be reviewed to cover inmore detail the elements of Good Practice infinishing works. Clients must be choosy on thelabour involved on their sites and why not insistupon the presentation of testimonial from theseTraining Institutes.


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Introduction Thousands of school leavers aspire every year toan engineering education, and hundreds of themactually graduate from various engineeringinstitutions, either locally or abroad. The trendsof wish-list over the years however seem to vary;in some years youngsters are more inclinedtowards IT and Mechatronics, while in others,they seem to favour the sure bet to a jobprovided by Civil Engineering, ElectricalEngineering or Mechanical Engineering,amongst others.

However, whatever the reasons to join theengineering field, and spend several yearsstudying engineering, the objective of nearly allthese students remain to be eventually able topractice engineering as a recognisedProfessional Engineer. It is a pity therefore to seeso many of them still being misguided ormisinformed about the academic requirement toachieve their objective in Mauritius.

What is an acceptable engineeringqualification in view of an eventualregistration?Practice of professional engineering in Mauritius,and its territories, requires an individual to beregistered as a Professional Engineer with theCouncil of Registered Professional Engineers ofMauritius (CRPE). CRPE registers an applicant as“Professional Registered Engineer”, as perSections 13 and 14 of the Registered ProfessionalEngineers’ Council Act (1966) when the latterholds a qualification approved by Council andafter having demonstrated, by way of a trainingreport and a technical interview, the satisfactorycompletion of a training period of at least twoyears.

These qualifications approved by Council differdepending on their origin, though the logicbehind the approval remains the same. Hence,for a Mauritian degree, in general, and withreservations regarding some newly approveddegree programmes, a four year full timeengineering degree programme, in at leastLower Second Division automatically meetCouncil’s requirement. For UK or any of thesignatories of the Washington Accord, theacceptable qualification is a four year full timeengineering degree programme, accredited bythe Engineering Council UK, or an equivalentbody from one of the Washington Accordsignatories, as meeting the academicrequirement, without further learning, to thegrade of Chartered Engineer, or equivalent.

Likewise, for an engineering graduate comingfrom France, the automatically acceptablequalification for CRPE is either a Diplômed’Ingénieur or a combination of a Licencefollowed by the successful completion of aMasters (1+2). Additionally, for someonegraduating from one of the engineeringinstitutions from India, it would be worth tonote that a degree in engineering from one ofthe Indian Institute of Technology isautomatically recognised by Council, whereasgraduates from other universities are requiredto undergo a technical interview to assesswhether their level of engineering knowledgemeets the requirement of someone suitable toundergo training in view of an eventualregistration. A list of approved qualificationshas been published by the CRPE and same canbe downloaded from its website.

Views on Engineering Education forDeveloping Mauritius

K Bhujun C.Eng MIEI M.ASCE RPEMRegistrar, Council of Registered Professional Engineers of Mauritius

[email protected]


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Continuing EducationDespite the high level of education undoubtedlyinculcated in engineering institutions in thestudents’ pursuit of an engineering degree,observations over the years have led to theconclusion that this engineering education isnever enough to last a career. In fact, ProfessionalEngineers nowadays more and more request andlook for Continuous Professional Developmentprogramme, as a means to update theirknowledge and awareness of the latesttechniques and technologies. CPD is currentlyalso becoming an increasingly required elementfor the renewal of membership with some of theinternational and reputed EngineeringInstitutions. The objective seems to be to urgeEngineers into realising the importance ofupdating their knowledge with the latesttechniques, with a view to remaining efficient andproductive.

Mauritius being geographically isolated from themajor engineering centres, there appears to be anincreasing and unsatisfied demand for these CPDcourses, in various forms, by with the localProfessional Engineers’ population. Hence,Council regularly receive request for informationregarding the conduct of specialised trainings;similarly, it has been observed that there iscurrently in Mauritius a real demand for formalfurther engineering education, in the form of ataught MSc in pure engineering, as opposed toengineering management courses.

Additionally, with the wide-spread promotion bythe Authorities in favour of pursuit of science andtechnology education, it comes as a surprise thatso little opportunity is available for interestedparties, students and working professionals alike,for further involvement in the form of research,leading to a PhD in Mauritius. It can be arguedthat research requires funding, which is mostlyavailable only to people who have previouslyproduced useful results for the industry, therebycreating strong links of trust. The counter pointhowever remains that results come from attempts(and failures) and require as a sine qua noncondition the first step to venture into research.How many are willing to do research in Scienceand Technology in Mauritius? At what cost? Howmany are interested but do not have anopportunity to do so? These are questions which,for the time being, remain unanswered.

Limitations of current engineering educationAlong with the needs from ProfessionalEngineers, observations have also shown aspectsof the engineering education which could beimproved to help the Mauritian engineeringgraduates. It is a fact that Professional Engineersare required, at some point of time in their career,to talk, explain, discuss, present and substantiatetheir observations of technical aspects of things.Research done elsewhere have revealed thatEngineers are generally stereotyped as someonewho would prefer to be alone at his desk,calculating and analysing observations ratherthan giving a lecture on something he just did, orwrite a report on his observation to the “lay-man”who invariably seems to control the decisionprocess. The same trends were observed overseveral years at the CRPE: engineering graduatesare afraid to talk (sense) and do not feelmotivated enough to learn how to and eventuallywrite a letter or a report, describing a technicalevent or occurrence, in simple terms, forwidespread communication of a problem or itsproposed solution.

There is need, in the current engineeringeducation, to teach engineering graduates someof the soft skills required in the workplace,namely, how to write a business letter, how toprepare and draft a technical report for non-technical people, how to prepare a PowerPointpresentation and also how to do an oralpresentation in front of an audience or morecontemporarily, how to write or reply to an email.How many times have we attended workshops orforum to find ourselves facing slides filled withsmall font size text, written with inappropriatecolours, poor background, inconsistent format, orworst, with the speaker looking at his laptop andrushing through the speech as if he wished to besomewhere else… Similarly, how often have wereceived letters, or emails, with the wrongbeginning, a poor salutation, inadequateparagraphing and too much elaboration, whichlead to the main point being often overlooked,thereby not allowing the letter to reach itsobjective. Email communication is a result oftechnological advances and has the advantage ofbeing very fast as compared to a traditional letteror a fax. It is just a click away and with this senseof speed comes a sense of urgency. We can sendour request or information quickly and we wantthe answer as quickly too. And to make our point


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clear, we emphasize the critical words, increasetheir font, make them look bold and red, or evencapitalize them, resulting finally in a colourfulwork of art, at best difficult, and at worstirritating, to read. Business communication is anart, and it would do engineering graduates aworld of good if they could be provided with tipson how to communicate effectively.

Objectives of Engineering EducationIndividuals pursue an engineering education fordifferent reasons, though the prime objective ofnearly all these students remains to beeventually able to practice engineering as arecognised Professional Engineer. This can onlyhappen in Mauritius by being registered with theCRPE. The procedure for application is availableon Council’s website: www.crpemauritius.com

In this regard therefore, it is the duty of differentengineering institutions to ensure thatconditions are present which creates a situationof sufficiency in engineering graduates on themarket. For example, the University of Mauritiusproduces in excess of 200 engineering graduatesevery year and still only some 40 to 50 of themget registered every year, which raise thequestions: “Where are the others?”. Where arethose others who proudly graduated with anengineering degree? Are they uninterested? Arethey not motivated to call themselves aProfessional Engineer? Are they not sure of their

abilities to meet the requirement to be aProfessional Engineer? Are they not being askedby their Employer to get themselves registeredbefore they can practice engineering? Suchquestions remain burning issues whose redresswould give a boost to the engineeringprofession in Mauritius. Additionally, theconditions for sufficiency should include thebold decision to halt or stagger intake for one ormore fields of engineering, should it beobserved, or reported, that the majority of thegraduating students do not obtain a job in theirfield, through lack of opportunity, as is the casefor the fields of Chemical Engineering orChemical and Environmental Engineering. Sucha decision could then contribute to reduce thesense of frustration in some of the younggraduates, who find themselves taking up a joboutside their field of studies, for the sake ofearning.

ConclusionThis article is an attempt to bring to thediscussion table the academic requirements inview of an eventual registration as a ProfessionalEngineer in Mauritius, as well as pin-point someof the non-technical elements whose inclusionin typical engineering education would helpimproved the latter while bringing added valueto the product. Comments and discussions onthe opinion expressed are always welcome.


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ABSTRACTTraditionally, Mauritian engineers have recourseto British Codes of Practice to carry out structuraland geotechnical designs. However, in the UK, theBritish structural and geotechnical design codeshave been withdrawn since March 2010 and havebeen replaced by Eurocodes. Geotechnicalengineers are the ones who are most affected bythe new codes because it is the first time that limitstates concepts are being introduced ingeotechnical design. The aim of this change is toharmonize structural and geotechnical designpractice. With these developments, the civilengineering practice in Mauritius is at a crossroadand will have to adopt a set of codes which aremost appropriate for the local context. TheEuropean geotechnical code, known as EC7:Geotechnical Design or BS EN1997, brings up-to-date design principles and good practices togeotechnical engineers. However, if Mauritianauthorities adopt EC7, firstly, they will face thechallenge of having to formulate an appropriateNational Annex based on local experience.Secondly, as EC7 consists of complex principlesand rules, an extensive training programme willhave to be designed for practicing engineers sothat they can fully understand the designprinciples and rules of the code and apply themcorrectly. Thirdly, EC7 requires high qualityground investigation results for thedetermination of design parameters so that aplan for accreditation of testing laboratoriescapable of meeting the requirements of the codemust be elaborated.

1.0 INTRODUCTION

Structural and geotechnical designs in Mauritiushave traditionally been based on British Codes ofPractice. However, in the UK, the British design

codes have been withdrawn since March 2010and have been replaced by Eurocodes.

Eurocodes have been developed so as to meetthe objectives set by the Commission of theEuropean Community in 1975 to eliminatetechnical obstacles to trade among Europeancountries and to establish a set of harmonizedtechnical rules for the design of constructionworks.

Under the Structural Eurocode programme, a setof ten standards have been published for thedesign of building and civil engineering works asfollows:

EN 1990 Eurocode Basis of structural design

EN 1991 Eurocode 1 Actions on structures

EN 1992 Eurocode 2 Design of concrete structures

EN 1993 Eurocode 3 Design of steel structures

EN 1994 Eurocode 4 Design of composite steel and concrete structures

EN 1995 Eurocode 5 Design of timber structures

EN 1996 Eurocode 6 Design of masonry structures

EN 1997 Eurocode 7 Geotechnical design

EN 1998 Eurocode 8 Design of structures for earthquake resistance

EN 1999 Eurocode 9 Design of aluminium structures

These standards are divided into a number ofparts and are accompanied by National Annexes.The purpose of the National Annexes is to providea means for a country that has adopted theEurocodes to elaborate on the NationallyDetermined Parameters (such as partial factors,correlation factors, etc) and country-specificdesign guidance that are to be applied.

With the above developments, the civilengineering practice in Mauritius is at a crossroad

Implications of Adopting Eurocode 7for Geotechnical Design

A. Chan Chim Yuk, Geotechnical Engineer

[email protected]


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and faces the challenge of opting for a set ofcodes that can be adopted promptly.

The purpose of this paper is to present anoverview of the main features of Eurocode 7(EC7:Geotechnical Design or BS EN1997) anddiscuss the implications for Mauritius ifEurocodes are to be considered for adoption bythe local authorities.

2.0 DESIGN PHILOSOPHIES

EC7 which replaces BS8002 (Code of Practice forEarth Retaining Structures) and BS8004 (Code ofPractice for Foundations) presents significantdepartures from traditional geotechnical designpractice. It is also a single code that coversgeotechnical design of foundations, anchorages,retaining structures and embankments.

The traditional approach which is based on thepermissible or allowable stress method followedin BS 8004 requires the geotechnical engineer todetermine the allowable foundation capacitythat will support the unfactored loads providedby a structural engineer. A design is assumed tobe safe if the permissible stress in the ground isnot exceeded. To take into account variability inthe properties of the ground and uncertainties inmeasurement of these properties as well asuncertainties in analytical methods, a singleglobal factor of safety is applied to the failureload to determine the allowable or design load.In order to also limit deformations orsettlements, high factors of safety are applied.For example, in BS 8004, factors of 2 to 3 arerecommended for foundation design. Themagnitude of the factor of safety is frequentlychosen so as to both limit deformations andprevent collapse.

EC7 introduces the concept of limit stateprinciples, which have been used in structuraldesign standards since the1980s, in geotechnicaldesign and requires the application of partialfactors to the source of uncertainty. The purposeis to close the gap between structural andgeotechnical design principles (Driscoll et al,2008) by providing a harmonized approach indesign when using different constructionmaterials such as concrete, steel andgeomaterials. This should lead to consistency in

design when considering soil-structureinteraction. The limit state approach has alsobeen introduced in the United States with theload and resistance factor design (LRFD)method.

In the limit state approach, a clear distinction ismade between ultimate and serviceability limitstates. The ultimate limit state (ULS) is associatedwith collapse or other forms of structural failure(Simpson and Driscoll, 1998) and is concernedwith the safety of people and the structure. Onthe other hand, serviceability limit state (SLS) isassociated with specified requirements relatedto the functioning of the structure such as theneed to limit deformations, vibrations andsettlement.

3.0 MAIN FEATURES OF EC7

3.1 Structure of the code

EC7: Geotechnical design consists of two parts,namely:

1. General rules (BS EN 1997-1: 2004)divided into twelve sections and nineannexes, and

2. Ground investigation and testing (BS EN1997-2: 2007) divided into six sectionsand twenty four annexes.

Distinction is made in clauses of the codebetween mandatory Principles which areindicated by the letter “P” after the clausenumber and Application Rules. Application Rulesare informative and not mandatory but theysatisfy the requirements of the Principles.Alternatives to the Application Rules are allowed,provided they satisfy the requirements of therelevant Principles.

The code is not to be considered as a designmanual. It does not include geotechnicaltheories or material behaviour models that are tobe used in design calculations. Its aim is toprovide a set of rules for conducting a designand ensuring the safety of the design. However,some useful methods that may be considered fordetermining earth pressures, bearing capacitiesand settlements are given in Annexes C to H.


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3.2 Classification of structures ingeotechnical design

It is the usual practice in the initial stage ofgeotechnical design to consider thecomplexities of a structure and of the groundconditions at a site to plan ground investigationsfor obtaining geotechnical parameters for thedesign. To assist geotechnical engineers in sucha task and for an assessment of the level of riskassociated with the type of structure, EC7introduces the following three GeotechnicalCategories that take into account the types ofstructure and loadings, the complexity of theground conditions and the level of risk involved:

· Category 1 comprises small and simplestructures, and negligible risks. Designmay be based on local experience andqualitative geotechnical investigations.

· Category 2 includes conventional typesof structures, no difficult ground orloading conditions and no exceptionalrisks. Routine ground investigations canbe undertaken.

· Category 3 includes very large orcomplex structures, exceptionallydifficult ground or loading conditionsand abnormal risks. Normally requiresmore ground investigations thanCategory 2 and possibly advancedtesting.

Clause 2.1(11) recommends that a preliminaryclassification of a structure according to theabove categories be undertaken before carryingout geotechnical investigations. It is to be notedthat the Geotechnical Categories are defined asApplication Rules and are not mandatory.Therefore, alternative methods of assessinggeotechnical risk may be adopted.

3.3 Design philosophies

The code specifies that limit states should beverified by calculation, prescriptive measures,experimental models and load tests, anobservational method, or a combination of theseapproaches. Clause 2.4.7.1 identifies five

categories of ULS relevant to geotechnicaldesign: loss of equilibrium of the structure or theground (EQU); internal failure or excessivedeformation of the structure or structuralelements (STR); failure or excessive deformationof the ground (GEO); loss of equilibrium of thestructure or the ground due to uplift by waterpressure (buoyancy) or other vertical actions(UPL); and hydraulic heave, internal erosion andpiping in the ground caused by hydraulicgradients (HYD). Verification of the ULSs iscarried out using partial load and resistancefactors.

STR and GEO are the limit states that are mostlikely to be considered in routine geotechnicalengineering design. For these ultimate limitstates, it must be verified that the design value ofthe effect of actions (Ed) does not exceed the

design value of the resistance of the ground and/or the structure (Rd), that is,

Ed ≤ Rd (Clause 2.4.7.3.1).

Actions include loads applied to the structureand the ground, and displacements that areimposed by the ground on the structure, or viceversa. The structural loads are defined in EN1990. EN 1997 gives a list of geotechnical actionsto be considered.

Clause 2.4.7.3.4 proposes three DesignApproaches to check that the GEO and STR limitstates are not exceeded. In Design Approach 1,partial factors are applied to actions and toground strength and two combinations ofpartial factors must be considered. InCombination 1, that partial factors are applied toactions whereas ground strengths andresistances are not factored so as to providesafety against uncertainties in the actions(Schuppener, 2007); in Combination 2, partialfactors are applied to ground strengths andvariable actions whereas non-variable actionsand resistances are not factored (Bond andHarris, 2008) so as to provide safety againstuncertainties in the ground strength propertiesand calculation models. In Design Approach 2,partial factors are applied to either actions oreffects of actions and to ground resistances. Thisapproach is more or less similar to the traditionalmethod of global factor of safety. In DesignApproach 3, partial factors are applied to either


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actions or effects of structural actions and toground strength parameters. The need to havethe three Design Approaches arose becausethere were diverse views on the selection of asingle approach. However, Frank et al (2004)express the opinion that, following theexperience that will be gained in the variouscountries, the three Approaches will be mergedin a single one in the future.

In order to implement EC7, a country will have tospecify in its National Annex which DesignApproaches are to be used. It is to be noted thatthe UK National Annex specifies the use ofDesign Approach 1 only.

Partial and correlation factors for ultimate limitstates and their recommended values are givenin Annex A of EN 1997-1. A country may opt tospecify different values for the factors in itsNational Annex.

For serviceability states, EN 1997-1: 2004 Clause2.4.8 requires that the effects of actions (such asfoundation settlements) do not exceed theirestablished limiting values. Annex H of EN 1997-1 gives some guidelines on allowabledeformations to normal structures.

3.4 Geotechnical investigation and designreports

Figure 1 which is reproduced from EN 1997-2summarises the process for obtaininggeotechnical design values. EN 1997-2 and theassociated testing standards give rules forcarrying out laboratory testing and fieldinvestigations. From the test results, derivedvalues of geotechnical parameters andcoefficients are obtained by theory, correlationor empiricism. On the basis of the derivedvalues, Clause 2.4.5.2 requires the cautiousselection of characteristic values on whichpartial factors are applied. Characteristic valuesare obtained from statistical analyses of thederived parameters when there is sufficient data.When there is a lack of data, characteristic valuesmay be selected with great caution fromstandard tables. In both cases, the code requiresthe selection of characteristic values to be“complemented by well-established experience”.

Figure 1 – General framework for the selectionof derived and design values of geotechnicalproperties

Clause 3.2.1(1)P states that geotechnicalinvestigations must provide sufficient data onthe ground and groundwater conditions at, andaround, the site so as to provide a properdescription of the required ground propertiesand to recommend reliable characteristic valuesof geotechnical parameters for design purposes.

Clause 2.8(1)P specifies that design assumptions,methods of calculations and results of theverification of safety and serviceability should berecorded in a Geotechnical Design Report. Thelatter should also include the supervision,monitoring and maintenance plan for theproject. A Ground Investigation Report is also animportant item to be included in the designreport as specified in Clause 2.8. The DesignReport is required for all geotechnical designs,even the simplest ones for which a single-sheetreport may be sufficient.

4.0 Discussion

With EC7, geotechnical design has beenintegrated into a set of structural design codeswhich makes it consistent with the limit statedesign philosophies used in structural design.This facilitates the very close collaborationrequired between structural and geotechnicalengineers in the implementation of building andcivil engineering projects. EC7 imposes rigour inthe geotechnical design process and guides theengineers in the risk assessment of their projects.The final Geotechnical Design Report will requirea holistic approach in the design process


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because, besides the design output which mustbe fully documented, a supervision andmonitoring plan during and afterimplementation of a project is also required.

If the Mauritian Authorities intend to adopt EC7,the first step will be to prepare a National Annexthat establishes the design approaches and thevalues of partial factors to be adopted locally. Thiswill present a challenging task in view of thelimited data available locally to support thechoice of a particular design approach and ofpartial factors. Secondly, as EC7 consists of quitecomplex principles and rules, extensive trainingprogrammes must be designed for practicingengineers so that the design principles can beunderstood fully and applied correctly.

Thirdly, EC7 requires high quality groundinvestigation results for the determination ofdesign parameters. This will require high standardtesting facilities, including adequately trainedtechnical staff. Consequently, a plan foraccreditation of testing laboratories capable ofmeeting the requirements of EC7 must beelaborated.

It follows from the above three requirements thatimplementation of EC7 is likely to be a longprocess and will require substantial funding.Therefore, the decision to adopt Eurocodes orother new codes must be taken urgently so thatlocal engineers can keep pace with recentdevelopments in building and civil engineeringdesigns.

5.0 Conclusions

EC7 presents up-to-date limit states designprinciples and good practices to geotechnicalengineers. It imposes rigour in the geotechnicaldesign process and guides the engineers in therisk assessment of their projects.

If the Mauritian Authorities intend to adopt EC7,they will face the challenges of having

· To formulate a National Annex thatestablishes the design approaches andthe values of partial factors to be adoptedlocally.

· To provide extensive training topracticing engineers so that the design

principles of the code can be understoodfully and applied correctly.

· To impose high quality groundinvestigation facilities.

To conclude, it is imperative that the decision toadopt Eurocodes or other new codes must betaken urgently so that local engineers can keeppace with recent developments in building andcivil engineering designs.

6.0 References

Bond, A. and Harris, A. (2008). Decoding Eurocode 7. Taylor &Francis, London.

BS EN 1997-1: 2004. Eurocode 7 – Geotechnical design, Part 1 –general rules. British Standards Institution, London.

BS EN 1997-2: 2007. Eurocode 7 – Geotechnical design, Part 2 –Ground investigation and testing. British StandardsInstitution, London.

BS 8002: 1994. Code of practice for earth retaining structures.British Standards Institution, London.

BS 8004: 1986. Code of practice for foundations. BritishStandards Institution, London.

Driscoll, R.M.C., Powell, J.J.M., and Scott, P.D. (2008). EC7 –implications for UK practice. CIRIA RP701.

Frank et al (2004). Designer’s guide to EN BS 1997-1 Eurocode 7:Geotechnical design – general rules. Thomas Telford, London.

Schuppener, B (2007). Eurocode 7: Geotechnical design -Part 1: General rules - its implementation in the EuropeanMember states. Proc. 14th European Conference on SoilMechanics and Geotechnical Engineering, Madrid, 24-27September 2007, 280 – 289.

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