geotechnical specifications: a delicate balance between ...€¦ · contract management for land...

11Royal Boskalis Westminster nv

CEDA Conference on Dredging and Reclamation

Dredging and Sustainability:How wide is the Gulf?

Geotechnical Specifications:

a delicate balance between desirability and availability

by

Art Nooy v.d. Kolff

Contract Management for Land Reclamation 2

Specifications/conditions::

maximum speed 300 km/hrmaximum speed 300 km/hr

maximum COmaximum CO22 emission 50 g/kmemission 50 g/km

colour car: blackcolour car: black

delivery 1 month after award of contractdelivery 1 month after award of contract

CEDA Conference: Dredging and Sustainability, Doha (Qatar), 6-7 May 20082


Different offers::

1.1. No offer: No offer:

cannot meet specifications/conditionscannot meet specifications/conditions

2.2. Conditional offer:Conditional offer:

red car painted black, maximum speed 250 km/hr, red car painted black, maximum speed 250 km/hr,

200 trees to be planted, reasonable price200 trees to be planted, reasonable price

3.3. Conforming offer:Conforming offer:

all conditions can be met, very high priceall conditions can be met, very high price



FRUSTRATION



Content::

Introduction

Design process and Technical Specifications

Case history Doha Airport

Concluding remarks



Design process (1)


structural requirements:

-required elevation of runways

-bearing loads of foundations

-allowable deformation of buildings


Design process (1)


structural requirements

desired properties fill mass:

-strength of fill mass

-stiffness of fill mass

-(density of fill mass)

-(permeability of fill mass)


Design process (1)



desired properties fill mass

boundary conditions:

-nature existing subsoil

-quality and quantity of fill available

-natural hazards (earthquakes)

-environmental restrictions


Design process (1)




boundary conditions

construction method:-equipment

-organisation of fill area

-soil improvement


Design process (1)




boundary conditions

construction method

feasible ?no


Design process (1)




Technical Specifications

boundary conditions

construction method

feasible ?yesno


grading (envelope, fines content)

plasticity

no organic or other deleterious materials

Technical Specifications (1)Fill material



relative density (in-situ density, minimum/maximum

dry density, cone resistance)

Technical Specifications (2)Fill mass



Relative density




dry density, cone penetration test)

relative compaction (moisture-density relationship, in-

situ density)

bearing capacity and compressibility (cone penetration

test, ..




strip foundation square footing

Reduction of stress increase below foundations




dry density, cone penetration test)

relative compaction (moisture-density relationship, in-

situ density)

bearing capacity and compressibility (cone penetration

test, plate bearing test, zone load test)




Case history Doha Airport (1):




minimum cone resistance 9 MPa, increasing with

depth

minimum relative compaction all fill above MSL

95% MDD (modified Proctor)

maximum settlement 25 mm at 150 kPa on plate

of 3 * 3 m, maximum load 187.5 kPa (zone load

test)

Specifications problem: specifications fill mass




various tests measuring the same property

undesirable

specifications were written without considering the

quality of the fill available

tests that measure the required properties directly

are preferable

do not ‘overspecify’

Specifications problem: concluding remarks



Final remarks (1)::Specifications must be result of rational design process

Site investigation borrow area in design phase

Specifications should be based on a feasible design

Specifications must be

- realistic

- relevant

- univocal

- achievable



Final remarks (3)::

Design Manual Hydraulic Fills by clients, consultants

and contractors under supervision of the CUR/CIRIA

([email protected])

at present participating:

Port of Rotterdam, RWS,

DHV, Witteveen & Bos, Arcadis, Deltares (GeoDelft),

Fugro

van Oord, Jan de Nul, DI, Boskalis


Contract Management for Land Reclamation 26CEDA Conference: Dredging and Sustainability, Doha (Qatar), 6-7 May 200822

geotechnical specifications: a delicate balance between ...€¦ · contract management for land...

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