coren paper for registered engineering personnel _ maliki muhammed

COREN ENGINEERING PERSONNEL: 2011

Maliki Muhammed of 41

COUNCIL FOR THE REGULATION OF ENGINEERING IN NIGERIA

PROFESSIONAL REPORT ON PRACTICAL EXPERIENCE

FOR MEMBERSHIP AS AN ENGINEERING PERSONNEL

POST-GRADUATE TECHNICAL REPORT

MALIKI, MUHAMMED ABDUL

B. ENG (CIVIL ENGINEERING), MNSE

UNIVERSITY OF NIGERIA, NSUKKA

FEBUARY, 2011



ATTESTATION

This is to confirm that Mr. MALIKI, Muhammed Abdul, a Civil/Structural Engineer with Metti Consultants entered upon the activities of the projects mentioned in connection with the company in this report.

Thank you.

Name:………………………………………………………………………………………………………………

Position:…..………………………………………………………………………………………………………

Company:…………………………………………………………………………………………………………

Sign:………………………………………………………………………………Date:…………………………



DEDICATION

This report is a dedication to all practitioners especially in the art, science and engineering families whose professional and distinct contributions have been insightful and have inspired the coming engineers to a great deal in reasoning out-of-the-box in their day-to-day engineering decision.



ACKNOWLEDGEMENT

My acknowledgment goes to the Bearer of Wisdom, God Almighty.

I have been indebted to the inspiring and conducive environment made possible by the Management and Staff of UF-A Consultants as a huge part of this report had been derived from the activities being performed while I was under the obligation of the company.

I have also acknowledge with gratitude the advise, encouragement and push of a respected senior colleague – Joseph Olabode Dayo and more so for the inputs and assistance of yet another colleague and a friend- Saheed Ogunniyi

To my family: The Malikis -I owe you everything.

My appreciation is incomplete without recognizing the efforts of various engineering governing/regulatory bodies of one of which constitute the reason for this report is the Council for the Regulation of Engineering in Nigeria, who through its campaigns has advanced engineering practice to a greater standard. God Bless COREN. God bless engineering practitioners in Nigeria.

Thank you.



TABLE OF CONTENTS

Contents Page

Title Page…………………………………………………………………………………………. 1

Attestation……………………………………………………………………………… 2

Dedication…………………………………………………………………….. 3

Acknowledgement………………………………………………… 4

Table of Contents………………………………………… 5

Part I

Introduction………………………………………………………………………………………. 6

Self Biography………………………………………………………………………….. 7

Bio-data…………………………………………………………………………. 8

Summary of Recent Jobs Executed…………………………. 9-10

Part II

Post Graduate Training and Experience………………………………………………… 11-36

Reference………………………………………………………………………………… 36-37

Proposal………………………………………………………………………… 37-38

Appendix I Bill of Engineering Measurement and Evaluation for NPA:

Nigerian Ports Authority

Appendix II Calculation Sheets for Twin & Rivers

Appendix III Calculation Sheets for Sancoemex Nigeria Limited



INTRODUCTION

This postgraduate training and experience technical report is written in partial fulfillment of the requirements for admission as an Engineer of the Council for the Regulation of Engineering in Nigeria.

This report touches on some of the projects of which I have assumed a core role and executed either independently or under the supervision of registered Senior Engineers.

It is a presentation of experience acquired in practice as a Civil/Structural Engineer through extensive conceptual, theoretical and practical training covered over a period of five(5) years of post NYSC proven experience which spreads around and cut across through Civil Works/Structural Engineering , Geotechnical Engineering, Oil & Gas, Telecommunication, Project Management and other related fields.

The report is the result of deliberate effort to summarize my post-graduate professional activities, both on-site and on-desk by focusing prominently on the activities performed by me, the problem(s) encountered in the course of such activities and solution(s) proffered from an engineering perspective to remedy the situations.



SELF BIOGRAPHY

My post-graduate experience history as highlighted below has been arranged in a past to present pecking order.

2005-2006: In line with the compulsory NYSC requirements I served as a Youth Corp member with Ikono Local Govt. Secretariat in Akwa-Ibom. As a Quantity Estimator and Pupil Engineer, I was responsible for project cost estimation and supervision of the secretariat’s community civil works projects.

2006-2007: I functioned as a Site Engineer/Quantity Estimator with Mariad Morh (Nig.) Ltd, a construction and aluminum company based in Lagos.

In June 2007, I joined Progress Engineers, a geotechnical firm located in Lagos. The firm is a major player in foundation engineering as well as soil sampling, identification and laboratory testing for soil classification and sub-soil strength determination.

In 2008, I joined Encon International Ltd in the capacity of a Project Engineer. I was involved in a series of duties. Part of such duties include structural designing, comprehensive report writing, safety management of traffic flow, economic study and assessment of projects such as the proposed Cable Stayed Bridge linking Lekki-Epe Expressway and Ikoyi in Lagos.

From 2008-2010, I was part of UF-A Consultant work force. At UF-A consultant I was able to gain experience that have constituted a huge aspect of my structural designing and site supervision capabilty given the application of state-of-the-art computer-aided design tools which include Staad Pro, Orion, Master Series, Ram Concepts, Scale etc. UF-A consultants is structured to provide design and plan residential, commercial, and industrial structures in compliance with relevant governing codes. I was chiefly responsible for structural design, detailing of reinforced concrete and steel structures for various purposes as for residential, commercial and mixed uses as well as site visitation/ inspection and attending various site meetings.

Between 2010 till date, I have been involved in reports writing on the condition assessment/integrity check of various lattice communication structures(towers/masts) including supervision, modification works on topsides structures and Platforms/Decks (Oil and Gas related). I presently owned my professional obligations to Metti Consultants as a Design/Project Engineer.



BIO-DATA

NAME: Maliki Muhammed abdul

SEX: Male

STATE OF ORIGIN: Edo State

PLACE OF BIRTH: Lagos, Nigeria

LOCAL GOVERNMENT AREA: Etsako East local Government

EDUCATIONAL BACKGROUND

DATE INSTITUTION ATTENDED QUALIFICATION OBTAINED

1985 - 1991 Ifelodun Primary School, Agege, L

First School Leaving Certificate

1991 - 1997 State High School, Agege, Lagos Senior Secondary School Certificate

1999 - 2004 University of Nigeria, Nsukka, Enugu State

B.ENG. (Civil Engineering)

2010 - Date University of Lagos, Akoka MPM (Master of Project Management)

PROFESSIONAL MEMBERSHIP Corporate Member: Nigerian Society of Engineers, NSE: 23454. PROFESSIONAL TRAINING

1 Level 3 & General Hse Training: Nigerian Institute of Safety Professional(NISP), 2010

2 Essential Software Solution for Structural Engineer: CSC, 2010 3 Oil & Gas Production Facilities Course: EPCM Engineers, 2009 4 Project Management Professional: BI-TRAX Axxent, 2009

PRESENT PLACE OF EMPLOYEMENT

METTI CONSULTANTS

7, BODE THOMAS STREET

SURULERE LAGOS

LAGOS - NIGERIA



STATEMENT OF EXPERIENCE AND RESPONSIBILITY

DATE FROM

DATE TO

POSITION, EMPLOYER AND DESCRIPTION OF PROJECT. Confirmed By

Nov.2010 - Date Project/Structural Engineer, Kunech Properties

Limited, Remodeling/design and supervision from 6 to

8 suspended floors(flat slab) of an on-going Car Show

Room & Office Building with Workshop Being Found on

Pile at Lekki-Lagos

Engr Arowolo Gomina

Dec.2010 Project Supervisor Civil, Inspection during Fabrication,

Supervision of the Construction of 45m Tower Foundation as

well as Erection of a Fixed Wireless Base Station Tower at No.

2 Seriki Aro Street, Ikeja, Lagos.

Maliki Muhammed

Dec.2010 Design Engineer, Weaver Ventures Ltd, Propose Prototype

Housing Units Design to include Blocks, Terraces, Recreational

Buildings for Oceanic Capital at Dideolu Estate, Oniru, Eti-Osa,

Lagos

Engr Arowolo Gomina

Nov.2010 - Date Structural/Project Engineer, Sterling Nig. Plc, Design Review

and Integrity Check for an on-going 7-Storey Office

Development/Plaza at Central Area-Abuja

Engr Arowolo Gomina

Aug. - Oct. 2010 Engineer, Chevron Nigeria Limited, Topside Installation and

Production Platform/Deck Modification on Escravos Gas

Project.

Dr. Moses

Iyengunwena

July – Aug. 2010 Engineer, Chevron Nigeria Limited, Evaluation of Concrete

Berge Tow Resistance and Strength Check on Concrete

around the Bollards on Dibi Development Project, North &

South Water Station

Dr. Moses

Iyengunwena

March – July 2010 Engineer, Shell Petroleum Development Company, Reports on

Structural Assessment/Integrity Check of Various Tower/Mast,

Rivers State

Dr. Moses

Iyengunwena

April 2010 Structural Engineer, Proposed Development for Justice

Ogunwunmi, Lagos

Engr. Olumide Fatoki,

March 2010 Structural Engineer, Formwork Limited, Design of a Proposed

18-Storey Mixed Use Development for Sancoemex Nigeria


Engr. S. Moshood



Limited @ Ahmed Onibudo Street, V.I., Lagos.

Feb 2010 Structural Engineer, Formwork Limited, Design of a Proposed

3-Storey Guest House Development for Joseph Gaba, V.I.,

Lagos.


Engr. S. Moshood

Jan 2010 Structural Engineer, Arctive Consultants Ltd, Design of a

Proposed 4-Storey Development for Twin & Rivers Nig. Ltd @

Ikoyi, Eti Osa L.G.A., Lagos.

Engr. Olumide Fatoki

Jan 2010 Structural Engineer, Integrated Projects, Proposed 3-Storey

Apartment for Ayodele Samuel @ Nicon Town, Lekki, Lagos

Engr. J.O. Olabode

Dec 2009 Structural Engineer, AEK Design Services/Archactive

Architects, Proposed 5-Storey Apartment @ Macdonard Road,

Lagos.

Engr. J.O. Olabode

November 2009 Structural Engineer, Formwork Limited, Design of a 7-Storey

Banking Hall for GTB @ Maitama, Abuja


Engr. S. Moshood

August 2009 Structural Engineer, Atubu & Associates, Design of a 3-Storey

Development @ Lekki Peninsula, Lagos

Engr. J.O. Olabode

July 2009 Structural Engineer, Landscape architect, Design of a Twin

Duplex Residential Estate @ Asaba, Delta State

Engr. J.O. Olabode

June 2009 Project Engineer, Design and Supervision of FTD Flats

Remodelling at bourdillon road, Ikoyi, Lagos.

Engr. J.O. Olabode

May 2009 Structural Engineer, Sanderton Ventures Limited, Design of a

3-Storey development for Lagos State Government Ministry of

Housing @ Lateef Jakande, Agidingbi, Lagos

Engr. J.O. Olabode

Feb 2009 Structural Engineer, Cyberspace, Design of a 3-Storey Office

Renovation for Visafone @ Saka Tinubu, V.I., Lagos

Engr. J.O. Olabode

Nov 2008 Project Engineer, AEK Design Services, Design and

Supervision of Residential development (5-Storey) for

Capanava Investment & Properties Ltd, at 2nd Avenue Estate,

Ikoyi. 50 million

Engr. J.O. Olabode

Aug 2008 Structural Engineer, Archetype Consults, Design of a

residential development for Treasury Components Limited,

Engr. Rotimi Antonio



Ikoyi, Lagos.

July 2008 Project Engineer, Archetype, Design of a residential

development for Treasury Components Limited, Ikoyi-Lagos


June 2008 Project Engineer, Report on the Structural Assessment/

Integrity of NPA (Nigerian Ports Authority) fire damaged

building/headquarters in Lagos.


April 2008 Project Engineer, Traffic Study, Economic analysis and

evaluation of a proposed Cable Stayed Bridge linking Lekki

Epe Expressway to Ikoyi, Lagos.


Feb, 2007 Geotechnical Engineer, Soil investigation and laboratory

testing for NLNG, Bonny Island for, PH.

Dr. Folayan

2006 Structural Engineer, Design of a Banking Hall for

Intercontinental Bank Plc, Ekpoma, Edo State.

Mattew

2006 Project Engineer, Structural Steel Work and Office BlockS for

Sona Breweries Nig. Plc, Sango, Ogun State

Mattew



POST GRADUATE TRAINING AND EXPERIENCE

1. Structural Steel Work and Office Blocks for Sona Breweries Nig. Plc, Sango, Ogun State

Sona Breweries Company is a factory that deals with the production and packaging of soft drinks. The factory comprises the manufacturing workshop, production workshop, packaging workshop and the block of offices. The workshops are framed with steel stanchions and beams. The structure is a portal frame structure of a UC/UB at 6m apart with cladding around it. The office block is a one storey building in reinforced concrete structure.

The design of the office blocks were done in reinforced concrete structure using the BS 8110. The first floor slabs were designed as 150mm solid slab with 230mm x 450mm deep down stand beams to stiffen the panels. The beams in turn transfer the load through the columns to the pad foundation.

The workshop was designed using the BS5950, choosing the appropriate

UB/UC sections. The stanchions transfer the entire load from the roof to the isolated footings.

Problems and Solutions Proffered

I had challenges using very efficiently the RCD software provided for the design being my first time, which invariably affected expected time of delivery. But with the constant intervention and monitoring of a senior colleague the pressure was lessen, all challenges resolved and work prepared and dispatched for implementation.



2. Structural Appraisal of Property at 58, Isaac John Street, Ikeja, Lagos.

The Client reportedly observed cracks on some beams (2No) framing the commercial residence located at No. 58, Isaac John Street, GRA, Ikeja Lagos State.

In consequence, my company was invited to carryout a detailed study of the affected beams. The objective of the appraisal was to ascertain the structural integrity and stability assessment of the building and advise accordingly with a view to prevent damage that may arise, if the observed situation remains unchecked.

Methodology employed

A detailed inspection and assessment was carried out. As-built structural drawings for the existing building were not available as at the time of inspection. In general the inspection was limited to visual inspection, physical examination to ascertain its present and possible foreseeable future state.

Observations

Two categories of distressed / cracked beams where observed with particular reference to loading arrangement. They are classified as category A and category B in this report.

Category A

This was a beam on the first floor. It supports its self weight, block wall above it and weight of adjoining slabs. It appeared to be simply supported and spans about 5.92m centers. It sustained vertical cracks (tension movement cracks) around its mid span and at sections close to its two supports.

Category B The second category was a lintel also on the first floor, which supports its self

weight, weight of block wall above it and a point load from another lintel of about 3.28m long, which frames transversely into it. The lintel sustained vertical cracks at a portion close to its mid-span where it supports adjourning lintel and at other portions similar to that of category A.



Report Information gathered through one-on-one interview revealed that:

Prior to observed distress, the beam in category A originally served as an

external structural member before an alteration effected through extension of the building to its south-wing.

The lintel in category B was introduced to support walls above it following the

demolition of a pre-existing partitioned wall to create an opening for gaining access into an adjoining cabinet which was formally a toilet enclosure.

Cracks in each mentioned categories where first observed in 2003/04 about a

year after alteration.

Cracks started off as small surface cracks, expanded and became more visible and pronounced with time.

Desk Studies Design Criteria

The beam described in category A, which at the time of investigation served as an internal structural element was original envisaged and designed as an external element. The design criteria employed to the beams profile before alteration was obviously different from its present loading conditions.

This section present a design philosophy that shows the amount of load that might have been superimpose on the pre-existing beams, which we believe, at the time of alteration was not cater for and as a result the optimum performance and stability of the element have been compromised.

Design Calculation Showing Approximate Load Increment on Beam

Type of support - Simply supported Width of extension - 4.53m

Floor thickness = 4530/20 = 226.5m: Assume 200m thickness

Loading:

Self weight - 24 x 0.20 = 4.80KN/m2

Partition = 1.50KN/m2



Finishes - 22 x 0.065 = 1.43KN/m2

= 7.73KN/m2

Live load = 3.0KN/m2

Design load = 1.4 x 7.73 + 3.0 x 1.6 = 15.62KN/m per m run

Shear force V = 15.62 x 4.53 / 2 = 35.38KN/m

Approximate maximum load added on beam = 35.38KN/m

Minimum envisaged load added on Beam:

This includes load transfer on beam minus wall load. This situation may be considered since the beam under consideration does not entirely have block wall above it.

Height of wall = 2.75m

Load exert by wall = 15 x 2.75 x 0.23 = 13.28KN/m

Minimum load on Beam = 35.38 – 13.28 = 22.10KN/m

The cracks observed on both categories A and B, which very likely, are the after effects of poor engineering decisions at the time when alteration works was being done, are suggestive of over-stressed beam elements. Such defects characterized elements subject to an overall critical (ultimate) loads for which such elements where not originally designed to cater for or withstand.

Conclusion and Recommendations

Subject to the assessment of the distressed structural elements of the building, it was safe to conclude that:

We could continue further assessment and monitoring of the cracks by including the use of:

(i) “Tell-tale” crack monitoring or/ and

(ii) Ultrasonic Pulse Velocity test device(s).

These tests, when employed, will ascertain if cracks still continue or not.

In the event when cracks progress; this may signifies weakening of the beam concrete profile due to limited load carrying capacity. In such case the following options below were presented as suggestive measures for correcting defects.



Repair for Category A

Option I:

The floor soffit around affected beam to be propped, beam demolished and reconstructed with improved design calculation and decision for the situation.

Option II:

Beam continuity is to be enhanced with the introduction of a 230 x 230mm column at a position coinciding with the mid-span of the beam while cracks are sealed up to prevent ingression of moisture.

Repair for Category B

Option I:

Both supporting and supported lintel to be demolished along with the block walls above them, which they provide support to. The demolition must continue to and stop at the soffit of the roof beam above the demolished block wall on lintels.

Option II:

Supporting lintel (cracked lintel) should be demolished and reconstructed with an improved design calculation that makes provision for and considered sufficiently the lintel that framed into it. The lintel needs to be reconstructed as a structural element by connecting it ends monolithically into receiving columns.

Plate

Vertical Crack on Beam. A Close-up View of Cracked Beam.



Vertical Crack on Lintel Crack at the Soffit Of Lintel alongside a transverse lintel



3. Structural Assessment/Integrity Check for NPA(Nigerian Ports Authority) Fire Damaged Building/Headquarters, Marina, Lagos

Fire reportedly gutted the sixth floor Boardroom and ancillary facilities of the Nigerian Port Authority (NPA) head office in Lagos, on 19 July 2008. The prompt response of the NPA staff and its fire department assisted by other concerned fire departments around the vicinity, limited the duration of the fire to less than three hours.

Our commission was for the assessment of damage and investigations of the building’s integrity and stability as a whole.

Problem Encountered.

Visual inspections carried out with photographs taken, suggested much of the furniture, ceiling and other timber related installations; glass fenestration and supporting metal frames and floor rugs as well as boarded partitions were extensively damaged and combusted during the fire.

Non-destructive void location/ bond tests and Schmidt-Hammer rebound tests were carried out on the reinforced concrete elements, which frame the enclosures. Much of the concrete lintels above doors showed signs of considerable voids/ hollowness, suggesting bond failure between concrete and embedded reinforcement.

Sandcrete block partitions that define and separate enclosures were extensively distorted by the fire and the “quenching” process of putting out the fire.

Overall rebound hammer tests confirmed the relatively high quality of work at the time of construction as well as its good upkeep over the years. However, the observation of a slight deflection to the roof slab resulting in sway to the partition block wall beneath it led us to discover an extensive 7.5 – 8.0m long crack concealed beneath the roof felt above the board room. Dye Tracer test confirmed significant seepage through this crack and hence the need to demolish and reconstruct the roof slab along with six (6No) failed reinforced concrete columns which support it.

Solution Proffered.

The assessed section of the NPA Head Office Building was obviously been subjected to extremely high temperature and stresses beyond the normal environmental expectations. This resulted in extensive deterioration, damage and failure to the various structural and non-structural elements within and around the sixth floor wing of the building. It was important to carry out repair works and



reconstruction of damaged structural components and others in order to prevent further deterioration and damage that may further occur so as to restore the building performance to meet its original design purpose and satisfactorily serves long as other parts of the NPA Office Block.

The recommendations for remedial works proffered are summarized as shown below:

Removals, Demolitions & Disposal

Disable/disconnect, dismantle and remove for disposal or storage all

electronics, electrical, mechanical and fixed installations within the affected wing of the building including cabinets, hard and soft furniture amongst others.

Remove all metal, ceramic and timber works installations including windows

and frames, doors and frames, ceramic toilet, kitchen cabinets and fixtures for disposal or storage.

The entire roof felting of the NPA main block should be removed and the

entire fire affected portion of the roof slab and supporting beams carefully demolished and carted away from site.

Demolish and cart away all sandcrete block walls (of 100mm, 150mm and 225mm thickness) including lintel beams above doors and windows within the six the floor enclosure.

Demolish all failed reinforced concrete columns from the roof level to the top

of the sixth floor slab. Exposing and retaining all reinforcing steel for inspection and further action.

Demolish and cart away or proper disposal of all debris on the floor including

floor finishing and screed above the sixth floor reinforced concrete slab, within the conference room, ancillary rooms and balconies.

Reconstruction and Finishes

Reconstruct demolished reinforced concrete columns in Grade 25 concrete (mix including reinforcements) to receive new floor slab and supporting beams.

Reconstruct the entire roof slab and supporting beams (including formwork

and reinforcement. Provide screed to top of slab and three layers of bituminous felting to top of slab, beams, and parapet walls.



Reconstruct walls, or enclosures and partitions using 100mm, 150mm, and 225mm thick sandcrete block walls, including lintel beams above doors and windows.

A chiseled surface at floor soffit prepared for Schmidt hammer test

Schmidt hammer test being conducted

An extensive 7.5 – 8.0m long crack concealed beneath the roof felt

A cross-section of glass fenestration and metal frames extensively damaged during the fire.

Schmidt hammer test conducted on a fire affected column

NPA building roof top



4. Residential Development for Capanava Investment & Properties Ltd, Ikoyi, Lagos.

The building is a 4-storey residential development consisting five floors. It is constructed in reinforced concrete frame with predominantly Hollow “Classic clay” pot as floor components. The structure is founded on pile.

Problem encountered.

Two column lines 230mmx230mm were cast incorrectly by the contractor as against 230mmx300mm as specified in the issued structural drawings, thereby reducing the columns section sizes and making them liable to being overstressed under working condition. The affected columns were those of 4th and 5th floors. A remodeling and analysis (with Staad Pro) of the structure using 230x230mm in place of the affected columns showed failure, hence strengthening of the columns was crucial.

Solution Proffered.

In ensuring that the reduced columns performed the role which they were being designed for: to providing adequate support for other building components framing into them and not to jeopardize the integrity of the structure as a whole, the columns were strengthen by increasing the columns section sizes to 450x450mm and corresponding area of reinforcement and this was done amidst provision for adequate propping system.

COREN

Maliki Mu

uhammed

EENGINEERING PERSONN

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5. Remodeling of FTD Staff Quarters at 20 Bourdillon Road, Ikoyi, Lagos

The structure is an existing 3 storey(four floors) building with an additional development of 3 suspended floors + a pent house(four floors) directly above but in isolation of the existing storey.

It is constructed in reinforced concrete frame which comprise mainly a combination of Hollow Classic Pots with some parts in Reinforced Concrete Slabs. The roof carcass is in steel truss supported on reinforced concrete roof beams and having its loads transfer down through reinforced concrete supporting columns to the underlying soil through pile foundation. Total floor area is about 2040 sq.m. Problem encountered

The 600x600mm external columns framing the structure were restrained but in one direction up to the starting off level of the new suspended floors which are about 10.2m from ground floor. While the restrained faces of the columns had their effective length reduce, there were speculations to reduce the slenderness of the unrestrained faces, otherwise they could be liable to distress under unforeseen critical external loading impact due to huge effective length possessed by these members. Hence the need to break the columns length in the unrestrained direction. However the option of concrete beams as restrained members wasn’t applicable as no connection or load transfer/exchange between the new and old structure was to be allowed.

Solution Proffered

A Slot Channel System mechanism was adopted to achieving the required restrained. A slot channel system comprises a built-up of steel elements of UB section, U channel section, end plate and Hilti bolts. Two (2no) vertical slot holes of 100mm each were core-out of the U channels which were attached to the legs of the column faces as the UB sections which also bear slotted end-plates to the interface of slot channel system were bolted with 300mm minimum embedment into the old structure with the use of Hilti bolts. An interface between the slot channel system and beam was then established by connecting both free ends with 2 nos of black bolts. With the installation of the system in place, lateral restrained was ensured about both axes of the columns while slight downward movement of the of the new structure may take place to cater for relative vertical displacement that could occur as the soil beneath the new structure settles relatively to the old one.



FTD 20 BOUDILLON FRAME GEOMETRY

PERIPHERAL COLUMNS RESTRAINED IN ONE DIRECTION

EXISTING STRUCTURE

NEW FRME

COREN

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6. Design and Supervision of a 7-Storey Banking Hall Headquarter for GTB, Maitama, Abuja

This is a commercial development for banking activities. GTB Maitama consists of 2 basement floors and 5 suspended floors (7-storey development) constructed in reinforced concrete. The basement floors are accessed externally through a 6.5m width, 71m span reinforced concrete driveway. The roof structure is partly in reinforced concrete slab and timber roof truss supported on reinforced concrete roof beams and it has all superstructure loads transfer to a raft base with a foot print of about 570sq.m.

The terrain slopes gently and has a flowing river to the west wing which

probably accounted for the high water table level that characterized the entire surroundings Problem Encountered

The contractor had challenge of ground water ingression into excavated work site through the adjacent flowing river source. This situation resulted into a water-logged condition thereby slowing down work considerably and causing safety problems such as erosion, collapse of the sides of excavation and partial flooding.

The contractor resorted to lowering the water table by pump sumping, a dewatering system, to no avail as the volume of water pumped out was continually being replaced by constant movement of uncontained body of water from the river source. Hence the needs for a rather permanent ground water control scheme.

Solution Provided

To curb the situation a retaining wall barrier media (ranging between 2.5-3.5m in height) known as water exclusion system was introduced to stop the water getting into the excavation. This did not only guarantee a cut-off of the river source, it also ensured the containment of back-fill as well as positioning the site safely for work progress. In essence the retaining walls which in addition to supporting the soil also provided barrier against the ingress of water, thereby ensuring safe work site.

COREN

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7. Design and Supervision of a Residential Development for Twin & Rivers, Banana Island, Lagos.

Problem Encountered.

Twin & Rivers is a 3-Storey residential apartment located on the Banana Island of Lagos. This region is known for its poor soil condition and as a result much of the buildings in the Banana Island region are found on piles.

In order to accomplish a rather cost-effective venture, the client requested for a design and hence an overall engineering output of the structure that could be developed without being founded on pile. A preliminary modeling and analysis of the structure was done with the application of Orion, a reinforced concrete design computer aided tool. The result of the analysis of the structure modeled on raft foundation showed an applied soil pressure of about 111KN/m2 as against 62KN/m2 bearing capacity of the soil as advised by the geotechnical expert.

The challenge was achieving a safe and stable structure without reducing the numbers of proposed suspended floors or advancing beyond the client request for a cost-effective implementation venture.

Solution Proffered.

Since the scope to keep the expense of the project within cost-effective limit was made known in good times, it was easy considering measure at achieving this at the conceptual design phase.

To cater for all loadings that may be bore by the underlying soil through the foundation without recourse to the use of piles for support, an apron was incorporated in the raft thereby spreading the raft footprint 1.5m beyond the building line. This enabled the envisaged building load being transferred over a wider floor area with a consequent mark reduction of the soil pressure to 61.2KN/m2. More so in reducing the building overall weight, the use of clay bricks as partitioning materials were adopted in lieu sancrete blocks. Clay brick is known to weigh 30% of sandcrete block.

COREN

Maliki Mu

TWIN A

APRON CONCEN

uhammed

AND RIVERS

EXTENSINTRATION

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RESSURE

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8. New Apartment Building McDonald Road, Lagos, Nigeria: The Axis.

Re: Analysis and Foundation Recommendation Report.

Introduction:

The Axis is proposed twin apartment buildings. Each building is further separated into 2-Unit by the use of a separation joint.

The buildings which comprise 3 and 4 suspended floors respectively are to be constructed in reinforced concrete.

For the purpose of this report, I have named each building unit as unit 1 (from -3m) and unit 2 (from -0m) according to their positions.

The aim of this report is to present the output of the foundation design.

Analysis: The analysis of the buildings have been done in accordance with the provision

of the relevant code, 6399 Part 1, and other associated guidelines and we have adopted the use of STAAD PRO for this analysis.

Adopted Geotechnical Parameter.

Foundation Type Depth (mm) Allowable Bearing Pressure (KN/m2)

Raft 2500 79



Table below showing results of the base analysis at serviceability state limits.

Start Off Level Base Pressure (KN/M2)

Unit 1 -3m 169*

Unit 2 0m 127*

Desk Studies

Consequent upon the results of our analysis which indicated proportionally high base pressures has summarized below: Unit 1. 169KN/M2 as against 79KN/M2: 114% higher. Unit 2. 127KN/M2 as against 79KN/M2: 61% higher. We decided to examine the option of a cellular raft. Result summarized below: Cellular Raft Analysis Consideration Proposed Foundation Depth = 2500mm. Ground Water Level = -1700mm

Density of dry soil: Yd = 18.00KN/m3 Density of water: Ywater = 9.81KN/m3 Density of submerged soil :Ysub = 18.00 – 9.81 = 8.19KN/M2

Base pressure of dry soil = 18.0 x 1.7 = 30.60 KN/M2 Base pressure of submerged soil = 8.19 x 0.8 = 6.55 “ Pore water pressure = 9.81 x 0.8 = 7.85 ”

45.0 KN/M2

Therefore the maximum expected allowable soil pressure for cellular raft =79 + 45 =124KN/m2

Hence, for a cellular raft option, we have a maximum allowable soil pressure which is less than the obtained respective base pressures of 127 and 169KN/M2.



Recommendation On the basis of the result of the analysis we had suggested mobilizing the soil

allowable bearing capacity to support the applied load by vibro-flotation, a soil improvement method.

We have deemed this method a better option as it would ensure retaining the separation joints in the buildings. The pile option can be considered while the separation joints may be compromised.

However, a clear definition of the proposed project constraints should provide

the leeway for a better of the two options.



9. Design of a Proposed 18-Storey Mixed Use Development for Sancoemex Nigeria Limited @ Ahmed Onibudo Street, V.I., Lagos.

The proposed project is an 18-storey building with a centrally positioned shear wall. All floors are to be constructed in hollow classis clay pots except in shear wall regions and ramp up that are to be in reinforced concrete. Though the building is to be found on piles, the ground floor is isolated as it is being supported on underlying soil grade. The ground floor has its foot print spread over an area of 460sq.m. Problems and Solutions Proffered

From first floor the building perimeter extended beyond authorized boundary/property line by 4.676m and 5.145m to the east and south wings respectively. Sequel to this development, there was the need to embark on the design of the structure such that it’s fit for purpose without downplaying the proposed building floor area as required by the client.

Columns were being provided to start-off from authorized boundary lines and raked to pick extended upper respective floors at edges. The condition was simulated by the use of a design software application called Orion and was found to have performed well according to expectations.

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10. Carshowroom, Workshop and Office Development for Kunech Properties Ltd at Osapa Village, Lekki Pinunsula, Lagos

The development was originally schemed and designed to serve for commercial purpose. The entire structure is divided into two parts according to its use, namely: The Main Building and The Workshop Unit. Each part is separated from the other by 50mm separation joint to allow for difference in settlement rate that may arise due to foundation differences and extent of other loading arrangement.

Main Building

This comprise of ground floor which serves as the car show room to be supported on well compacted underlying soil grade and six suspended floors being stiffened by adjoining beams and all loadings considered are transferred through supporting columns into the bearing soil through pile foundation arrangement.

Workshop Unit

As the name already suggest, the ground floor of the workshop unit is an open space which serves as a car workshop. It contains a Mezzanine(first) floor whose floor area make up less than 1/4th of the workshop (ground)floor. Its roof level is at the second floor level of the Main Building with self supporting steel lattice roof trusses spanning about 16.7m. The foundation is a combination of raft, isolated and combine footings which as a whole covers a footprint of about…….

It is important at this point to mention that the main building aspect has constituted technical challenges upon which this report is to be based.

The Challenges

At construction stage midway into pile installation, the Client through the Architect saw and communicated the need to increase the numbers of proposed floors from 6 to 8.

Consequent upon this requirement, the challenges/ problems encountered are highlighted herein.

From the soil report, the geotechnical results advice a 600KN SWL of 600mm diameter pile bored to a depth of 15m due to high water table. This was the size adopted for construction(see pile layout)

Following a redevelopment/remodeling of the structure to reflect 8 suspended floors using Orion, a computer aided design software and subsequently loading it, the post-processing generated service column loads results at the



ground floor showed that an average of 750KN SWL of pile capacity was what required to sufficiently sustaining the superstructure. Hence making grossly inadequate the provided 600kN SWL pile(See reaction load fig…..).

The architect also informed us of the client desire to maximize each floor headroom especially in the offices floors.

SOLUTION

WORKING LOAD FOR 600mm DIA. BORE PILE

Working load for 600mm dia. Bored pile installed to 15m depth has been calculated based on the subsoil investigation repor by Labion Geotechnics Ltd.

Considering borehole log 1 & 2, it is seen that pile depth recommended is 15m and it is technically viable.

End Bearing Resistance of Pile - Qb

Qb = Area at base (Ab) x Cone resistance at toe(Ckd)

Where Ckd = Cone resistance at toe is given by

= 4 x Nav (where average SPT ‘N’ value at base is taken from BH 1 & 2)

= 4 x 15

= 60kg/cm2

Qb = Ab x Ckd

= /4(0.6)2 x 5880

= 1662KN

Shaft Resistance, Qf

Negleting top 2m layer, being loose filled up sand layer.

Average ‘N’ SPT value for 3m to 15m depth is 11 and unit skin friction is given by Meyerhoff’s relationship,

K= 4N/2 for bored piles

K = 4 x 11/2 = 22



Reference

UF-A Consultants Library

Manuals of StaadPro structural software

Manuals of Orion

Manuals of Master Series

Mosley, W.H & Bungey J.H. (1990) Reinforced Concrete Design, Macmillan Press Ltd.

Oyenuga, V.O (2001) Simplified Reinforced Concrete Design, Asros Ltd.

Oyenuga, V.O (2002) Manuals on Reinforced Concrete Design Software, Asros Ltd.

www.uf-a.com

www.progressengineers.com



PROPOSAL

This report is written to testify to my personal involvement and contributions to various projects in the area of Civil/Structural Engineering practice since graduation in September 2004.

In my quest to be a seasoned professional in the field, I have been practicing with a huge drive and positive attitude which I believe are derivable from my passion for excellence for the practice. One on end of the spectrum, the experience acquired have been challenging and in order to meet up and surpass expectations I have challenged myself to keep improving and upgrading my knowledge and skills while keeping an open minded approach to intelligent contrary engineering views. On the other end of it, I have been envisioned to take my engineering practice to an enviable height as it remains one of the professional endeavors that is geared towards providing one of mans basic needs of life: Housing and Infrastructure.

In view of this, I propose to be admitted as an Engineering Personnel of the Council for the Regulation of Engineering in Nigeria. If admitted, I would abide by the code of conduct and uphold the ethic of the society in the practice of the engineering profession.