construction and survey accuracies for the execution of rockworks

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Construction and Survey Accuracies

for the execution of rockworks

Eric Peeters | 30-09-2014

Dredging and Marine Contractors

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Best practices from the

“Maasvlakte 2”

Port Expansion Project


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Personal

─ Eric Peeters

─ BSc in Hydrography

─ Chief Survey Maasvlakte2 and responsible for:

− Survey Test pit

− Survey crane “Condor”

− E-Crane “Blockbuster”

− Daily survey operations Hard sea wall

− Managing MV2 survey department

─ Software test engineer HQ Rotterdam

Introduction


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Index


1. Introduction 2. Construction

Aspects 3. Surveying 4. Evaluation of

construction

accuracies and

survey

accuracies

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PUMA

Boskalis 50%

Van Oord 50%

MV2

─ Value 2.9 billion Euro

─ Final completion 2030

PUMA

─ Value 1.1 billion Euro

− Includes Sea defenses

− Includes Reclamation

− Includes Infrastructure (BAVO)

─ Completion 2013


Project Background

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Contract 1

Dimensions

─ Hard sea defence 3.5 km

─ Beach and dunes 7.3 km

─ Port basins 530 ha

─ Port area 700 ha

─ Quay wall 3.5 km

─ Road 13 km

─ Rail 14 km

Quantities

─ 240 million m3 of sand

─ 7 million tonnes of rock

─ 20,000 concrete blocks (40t/pcs)


Project Background

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Design – Construction - Survey

Design

─ Contractual specifications / requirements

− Unrealistic, unachievable or unnecessary strict requirements

Construction

─ Practical limits

− Costs

Survey

─ Surveying errors

− Systematical

− Random

Client and contractor to have a better understanding at start of entire process


1. Introduction Construction and Survey Accuracies for the execution of rockworks

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Innovative design features

Withstand 1/10,000 year storm

─ Wave height 9m

─ Wave direction North, North-West (348°)

─ Duration of 12 hours

Soft sea defence

─ Use of Pleistocene sand

− Steeper foreshore

Hard sea defence

─ Re-use of MV1 materials

− 2 million tones of quarry stone

− 20,000 concrete blocks



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Hard sea defence

“Stony dune with a reef of blocks”



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Vertical accuracy

─ Equipment type

─ Work method

─ Size and grading of rock

─ Ambient hydraulic conditions


2. Construction aspects Construction and Survey Accuracies for the execution of rockworks

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Specialized Equipment

─ Ability to place 40 tons concrete blocks at a distance of 50m within 10cm.


2. Construction aspects Construction and Survey Accuracies for the execution of rockworks

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Inaccuracies as a result of the quality of the survey system

Quality of the installation

─ Software, sensors, platform geometry, corrections for draught, heave, roll and pitch

Quality of operation

─ Calibration of the equipment has been executed sufficiently precise and frequent

─ Version control and settings

− Protocols & instructions

─ Pre-define amount of coverage / point density

─ Processing


3. Surveying Construction and Survey Accuracies for the execution of rockworks

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Defining accuracy

The survey accuracy can be defined as the extent to which a collection of individual observations actually reflects the true situation

Average level (macro tolerance) Minimum level (micro tolerance)

Large area 400*Dn502 Small area 16*Dn502

Systematic errors

─ Error which produces a systematic offset between observed values and the true values

− E.g. incorrect tidal values, incorrect draught, incorrect speed of sound

Random errors

─ The random error is the difference between the value of an individual observation at one location and moment in time compared to the average value which would result from a long series of observations at the same location



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Hard sea defence

Progress drawing



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Hard sea defence

As-Built drawing



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Testpit

PUMA (2010) vs Verolme (1999)



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Above water / Surf zone

Standard method (CUR 154)

─ Use of a semi-spherical foot

− Diameter of half the nominal average stone diameter (D = 0.5 x Dn50)

− 1m x 1m grid

− Reference level ± 10-15% below top

Alternative methods

─ Use of a square plate of 1m2 and 4m2 (± 4 x Dn502)

─ Point measurements

─ Crane Monitoring System

− Bucket or grab

─ Static and mobile laser measurements

− Including airborne systems


3. Surveying Construction and Survey Accuracies for the

execution of rockworks

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Under water / Surf zone

Accepted method

─ Multibeam systems

− 6 different types of multibeam

− 101 - 256 beams (3°-1.5°- 0.5°)

− Full coverage

− Lower volume detected

Alternative methods

─ Single beam

− Standard (7°) and narrow beam (3°)

─ Echoscope

− 3D acoustic camera

− 16.000 beams (0.3°x0.3°)

─ Crane Monitoring System



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Are there any questions?


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Thank you for your kind attention

Van Oord | Marine ingenuity

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construction and survey accuracies for the execution of rockworks

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