Spreadsheet for wharf load rating

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HYDROCARBONS | MINERALS, METALS & CHEMICALS | INDUSTRIAL & INFRASTRUCTURE | POWER & DEVELOPMENTS

4-Dec-06

Maritime Structures Conference

The Design of Wharf 10 at Port of Brisbane and the Development of a

Deck Load Capacity Programby Don Cooper

Introduction

1 Wharf 10 Project Background2 Wharf Geometry3 Wharf 10 Model4 Development of the Pad Load Program

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1 Wharf 10 Project Background

�TimelineInvitation to Consultants – 13 September 2005Proposal submitted - 4 October 2005Award of Consultancy to WP – 28 October 2005Tenders for Construction – 1 March 2006Close of Tenders - 06 April 2006Award of Contract - 15 June 2006Estimated Contract Completion Date - First half of 2008

Scope of Consultancy

�Model the Wharf Structure and check the design based on Wharf 9

�Amend the Wharf 9 drawings for Wharf 10.

�PBC’s tender documents specifically asked for the wharf to be modelled using Microstran

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WorleyParsons’ Proposal

�Conforming tender submitted for a MicrostranModel

�Non-conforming option submitted for a Strand7 finite element software to model the wharf

�WorleyParsons’ conforming proposal for the Micrstran model was accepted

�At the Start Up meeting, discussion was held regarding the Strand7 option.

�The advantages of using Strand7 were put forward as follows:

More realistic way to model the structure with the slab and beam elements modelled in their true positions.Plate elements properly model the stiffness of the deck.High quality graphic displays Viewer interface allows PBC to view model

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�WorleyParsons’ commission was extended to include both Microstran and Strand7 models.

2 - Wharf 10 Geometry

�Wharf 10 is a continuation of the existing wharves at Fisherman Islands.

�Accordingly, the design of Wharf 10 was based on the design of the preceding wharves.

�Wharves 1 to 8 were designed by PBC�Wharf 9 was the first wharf to be designed by an

external consultant.

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�372.2m long x 37m wide�Expansion joint at Ch 198.1m (two sections

198m/174m)�Dredged depth RL-14.0m LAT�Provision in the design for future dredging to

RL-16.0m LAT�(Note: RL-0.0 LAT = RL-1.243 AHD)


�Five rows of piles:Row A - 1050ø x 12 vertical piles supporting the front crane beamRows B, C & D - 900ø x 12 vertical piles supporting the deckRow E - 1200ø x 16 vertical & raking piles supporting the rear crane beam

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�Pile Longitudinal Spacing:6m longitudinal bent spacing typical5m longitudinal bent spacing at crane tie-downs6.325m transverse spacing (=25.3m/4)

�Pile Protection:Impressed current cathodic protection systemPiles wrapped with Denso Seashield Series 100 tape from soffit to RL0.5



�Deck:550mm to 650mm thickHorizontal soffit1:125 Fall on surface to central drains1:500 Longitudinal rise in deck from Ch0.0 to Ch174.5, level thereafter

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�Crane Beams:2.4m wide x 1.435m deep

�Abutment & Relieving Slab (600mm thick)�Existing Rock Wall�Fenders at 12m centres�100 tonne bollards at up to 18m centres�200 tonne bollards at rear of wharf

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�ServicesStormwater collection & treatment system for deck runoff.100 DICL potable water main to three locations at the front of the wharf.300 DICL fire main at the rear of the wharf at up to 70m centres.Power for Quay Cranes.Provision for electrical & telecommunication outlets at the front of the wharf.

3 - Strand7 Model

�Piles – Modelled as Beam elements – 191 �Deck & Beams – Modelled as Plate elements –

18,612 �Fender Blocks – Modelled as Brick elements –

2,448�Mesh spacing on deck – 500mm x 500mm�Total of 27,683 nodes

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3 - Strand7 Model

�Geotechnical Conditions:Medium dense sands & stiff clays to RL-34mVery dense gravel and sand from RL-34 to RL-40Weathered basalt below RL-40

�Piles modelled as fixed ended with embedment between 3.5D and 6.5D

�Comparison with pin end and translational & rotational springs – not critical

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3 - Strand7 Model

�Load Cases:Primary load cases: 84Combination load cases:

– Ultimate Limit State : 153 load combinations– Serviceability Limit State : 118 load combinations

3 - Strand7 Model

�Beams & Slabs – Mxx, Myy and Mxy results converted to W&A moments.

�Reinforcement checked & all OK�Piles - Structural capacity checked to AS4100

for combined axial/bending – all OK�Piles – Ultimate Geotechnical Strength Rug

adopted from Wharf 9, øg (=S*/Rug) back-calculated – all acceptable

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4 – Development of Pad Load Program

� The Problem ?

Unusual or expected loads to be placed on a wharf in excess of original design loads

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4 – Development of Pad Load Program The Problem Definition

� During the design period for Wharf 10, PBC raised questions regarding the capacity of the deck to carry pad loads from mobile harbour cranes – 28 scenarios.

� In considering the response to these questions, WorleyParsons developed the idea for the Pad Load Program.

� The aim was to develop a program that would allow PBC to assess the deck capacity for any load situation.

� The suggestion was put forward to PBC and the idea was readily accepted, and WorleyParsons was commissioned to develop the pad load program.

� The choice to adopt and use the Strand 7 finite element package is a crucial factor in the ability to create this system.

What does it do?

� The program allows the user to enter any combination of loads onthe deck, via a speadsheet.

� The program then assesses the load combinations and reports to the user whether the load combination is within the capacity of the deck.

� The program works for vertical live loads on the deck.

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General Approach

� If internal structural actions throughout the entire structure for a load on each individual element is known, then for each element that is loaded we can add the individual effects at each point in thestructure to obtain the total internal structural actions.

Aim of System

�Need to determine from a predefined pattern and level of loading “Q” how much the predefined pattern and loading can be multiplied by a ratio “r” to fail the structure.

�1.2G + r(1.5Q) � maximise rIf r=1 deck is at capacityIf r<1 deck capacity is exceededIf r>1 deck has spare capacity

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System Requirements

� Set of internal action files.

� Set of internal strength files.

� Method of defining loading pattern and level of loading.

� Method of searching for the maximum “r” value by doing supposition of relevant element loads, adding in self weight, comparing with strengths, and adjusting “r” till failure reached.

1.2G + r(1.5Q)

� Need to identify failure type and location.

System Overview

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System Requirements


Load Data Files

� It is possible to automate Strand 7 to apply a 100 kPa load to each element in turn, analyse the structural model, then file critical pieces of information in binary data files.

� Automation is achievable through the API (Application Programming Interface) of Strand 7 and using the C++ programming language.

� 3,534 individual runs are required plus another one run for the self weight.

� It took 28 hours run time to achieve this.� Once data is created it need never be created again.� Data is stored in binary files in an established ordered directory

structure that should not be altered.� Only data for two portions of deck can be practically stored. Called

block A and B.

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Internal Action Data Storage - Moment

� Plate moment data is stored for Mxx, Myy, & Mxy at four gauss points in each element. That is for 7,936 points block A and 6,200 points in block B.

Internal Action Data Storage - Shear

� Plate shear data is stored for Qxz, and Qyz at four gauss points in each element.

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Internal Action Data Storage - Piles

� Pile data stored is the resultant moment and axial load at top and bottom of pile. Bottom of pile represents point below ground surface at maximum in ground pile moment. 18 piles are located in each of blocks A and B.

System Requirements


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Strength Data Files

� The strength in flexure in each direction and for both sagging and hogging has been calculated for each element gauss point and stored in data files.

� Four files are stored for each block.Sagging LateralSagging LongitudinalHogging LateralHogging Longitudinal

System Requirements


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Definition of Pattern Loading

� Excel spreadsheet or Text editor can be used.� Define which block – first line.� Elements defined by which position laterally across deck, which

position longitudinally, then kPa value for that element.� Each element on individual line.� Sample File that loads three elements

B25 19 50.010 25 50.07 8 25.0

� The Excel spreadsheet “PatternLoadings.xls” makes creation of these files easy.

Definition of Pattern Loading - Excel

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Input of Load on Defined Pattern

� Press the [Calculate Areas] button once pattern shape is defined.� For each of the highlighted ranges or pads asked in turn what the

load is by a dialog box.� Order is order that pads are created in the pattern.

� Press [Save Pattern] to write pattern to “Pattern Export” worksheet from which it can be saved as text.

System Requirements


1.2G + r(1.5Q)

� Needs to identify failure type and location.

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Reading Pattern Files and Solving for “r”

� Execute the program “Wharf10_Loading.exe”

Search Algorithm for “r”

� Need a robust computer algorithm for searching for the maximum rvalue

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Wood-Armer Moment Combination

� The moments derived from the FEA analysis include Mxx, Myy, and Mxy.

� These need to be combined by a set of well known interaction formula called Wood-Armer to obtain the design moments in each orthogonal direction to check against strength of reinforcement.

� The interaction needs to be applied each time the value of “r” is changed.

1.2G + r(1.5Q)

Solution and Q/A

� Program can create a record of its processes and solution

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System Requirements





1.2G + r(1.5Q)

� Needs to identify failure type and location.

THANK YOUTHE END

Don CooperQueensland Marine Manager

WorleyParsonsTel: +61 (0)7 3319 3373Mob: +61 (0)437 708 212Fax: +61 (0)7 3221 7791

Spreadsheet for wharf load rating

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