MIDAS Expert Engineer Webinar Series Case Study ... Academy...MIDAS AU Expert Engineer Webinar...

MIDAS AU Expert Engineer Webinar Series

MIDAS Expert Engineer Webinar Series

Case Study: Incrementally

launched Bridge

Yeuk-Ho Goei,

Associate Director

AECOM Australia


Introduction

• Personal Profile

• AECOM


Personal Profile

Yeuk-Ho Goei • 16 years of experience in bridge engineering

• Go-Between Bridge (Brisbane, QLD) – in-situ balanced cantilever bridge with

117m main span

• South Road Superway (Adelaide, SA) – 2.8km long viaduct built by precast

segmental balanced cantilever method

• Omega Bridge in Gerringong Upgrade Project (Gerringong, NSW) – 345m long

incrementally launched prestressed concrete bridge

• North West Rail Link (Sydney, NSW) – 4km rail viaduct built by precast

segmental span by span method

• Darlington Upgrade Project (Adelaide, SA) – Composite box girder bridge built

using self propelled modular transporter (SPMT)

• West Gate Tunnel Proof Engineering (Melbourne, VIC)


AECOM is built to deliver a better world. We design, build, finance and

operate infrastructure assets for governments, businesses and organizations

in more than 150 countries. Our markets include: Cities, Commercial &

Residential, Education, Government, Healthcare, Industrial, Leisure &

Hospitality, Oil, Gas & Chemicals, Power, Sports & Venues, Transportation,

Water.

AECOM’s global bridge offering:

We’ve punctuated our 80 years of experience by designing, developing and

managing some of the world’s most striking long-span and complex bridges.

Our bridge practice is led by world renowned engineers who tailor each and

every program to meet our clients’ specific needs. We provide such services as:

• Bridge planning

• Modelling

• Design

• Alternate delivery

• Erection calculation

• Construction supervision

• Bridge inspection, maintenance and management

Fast facts:

• 87,000 staff globally

• 3,000 staff across Australia, with local operations in Melbourne totaling 700 staff, and an additional 800 within ANZ.

• AECOM was formed by the merger of five entities in 1990, some dating back more than 115 years

• Publicly listed on the New York Stock Exchange in 2007, reported US$20.2B revenue for the 2018 financial year

• Ranked #1 in Transportation and General Building in Engineering News-Record’s 2019 “Top 500 Design Firms”

• Ranked # 157 on the Fortune 500

• Named one of Fortune magazine's "World's Most Admired Companies" for the fifth consecutive year


INCREMENTAL LAUNCHING - INTRODUCTION

• A method to overcome access problems or minimise disruption at ground level

• Special knowledge and high degree of temporary works integration are required

• Generally used for bridge spans less than 60m• Two distinctive analysis stages• Two distinctive group of prestress


1 Design of Launch Geometry

2 Temporary Works

3 Temporary Works in Midas Model

4 Cross Section of a Launched Bridge

5 Analysis using Midas Civil

6 Launching Stage Analysis

7 In-service Stage Analysis

8 Section Capacity Check to AS5100

9 Deflection due to Permanent Effects

CONTENTS


• Launch geometry is defined by:• Coordinates and level of centre• Radius• Inclination of axis of rotation• Bearing angle of vertical radial section

• Circular arc in 3-D space. • Launch geometry does

not match roadalignment in terms of • Coordinates• Level• Crossfall• Bearing angle at

supports

Centre of launch geometry

Radius of launch geometry

Axis of rotation

VerticalLaunch geometry

Vertical radial cross section

DESIGN OF LAUNCH GEOMETRY

Vertical plane


DESIGN OF LAUNCH GEOMETRY

Abutment A from road geometry

Mid-point between A and B along road

geometry

Abutment Bfrom road geometry


Launch nose

Temporary tower

Casting bed

Launchjack

Braking saddle

Pulling frame

Table form

Launch bearing

Side guide

TEMPORARY WORKS


Temporary Works Input to Midas Output for design

Casting bed Vertical stiffness Support reaction

Launch nose Modelled as beam elements

Bending moment and shear force

Temporary Tower Vertical and rotational stiffness

Support reaction

Launch jack and braking saddle

N/A Support reaction at launch abutment to determine available friction

Pulling frame Self weight as load N/A

Temporary bearing Vertical pier stiffness Support reaction

Side guide Lateral restraint N/A

Table form Self weight as load N/A

TEMPORARY WORKS IN MIDAS MODEL


First pour

Second pour

Cross fall at bottom flange

Bearing eccentricity

Continuous path for table rolling of table form

1% fall

Webthickening

Tendon ducts and

anchorages

CROSS SECTION OF A LAUNCHED BOX GIRDER BRIDGE


CROSS SECTION INPUT IN MIDAS


ANALYSIS USING MIDAS CIVIL

Go through the set up of model from Midas


Purposes of launching stage analysis:• To ensure the stresses in the superstructure during launching comply

with the appropriate requirements. • To evaluate the load during launching for the design of launching

nose, temporary bearings, temporary pier, launching abutment andcasting bed.

• To calculate the cumulative shortening of bridge deck due to prestress, creep and shrinkage during construction.

LAUNCHING STAGE ANALYSIS


MOMENT ENVELOPE FROM LAUNCHING STAGE ANALYSIS


• Identify critical stages from the moment envelope by comparing the result of each individual stage with the result at “Max/Min” Stage

• Save critical stages as separate models• Apply various transient effects to the saved models

TRANSIENT EFFECTS AT CRITICAL LAUNCHING STAGES


Lapping Coupling

Higher stressing force / strand Occupy less space

Strands installed after reo fixing Simpler details

More congested flanges Strands cannot be replaced

Require additional reinforcement Smaller jacking force / strand

Longer tendons Strands interfere with reo fixing

ARRANGEMENT OF LAUNCHING PRESTRESS


REACTION POSITION TABLE


Additional segment casting length to compensate• Elastic shortening• Creep• Shrinkage

Cumulative segment shortening can be obtained from Midas

Diaphragms and piers / abutments are not in line

SHORTENING OF SEGMENTS


Transient Effects• Road traffic (Influence line analysis)• Thermal effects (Beam section temperature)• Wind• Differential Settlement• Bearing replacement

Design envelopes and co-existing actions can be conveniently obtainedfrom Midas

IN-SERVICE STAGE ANALYSIS


• SLS Bending Stress at Tendon level for Exposure B2, C1, C2, U(AS5100.5 Clause 8.6.2.3)

• SLS Stress Increment Check (AS5100.5 Clause 8.6.2.1(b)• ULS Bending Moment Capacity (AS5100.5 Clause 8.1)• ULS Shear and Torsion Capacity (AS5100.5 Clause 8.2)

Note the requirement of VicRoads BTN025• Transverse Analysis• ULS Longitudinal Shear at CJ and Web / Flange Interface

(AS5100.5 Clause 8.4)

SECTION CAPACITY CHECK TO AS5100


Internal Prestress External Prestress

Larger eccentricity Max length about 300m

Higher strength at ultimate Lower immediate prestress loss

Efficient tendon profile Easier installation

Max length about 150m More expensive hardware

More complicated segmentconstruction

Provision for future replacement

CONTINUITY PRESTRESS


• Deflection of bridge can be output from Midas• AS5100.2 Clause 7.11 requires no sag deflection under permanent loads• Self weight will create sag deflection• An incrementally launched bridge cannot be pre-cambered• Uneconomical to eliminate sag deflection by continuity prestress • Assess the effect of net sag deflections of the bridge for

• visual impact• required clearance underneath the bridge• bridge deck drainage• loading (e.g. extra surfacing thickness)

• Dispensation from the asset owner

PERMANENT LOAD DEFLECTION


Thank youEmail: [email protected]

MIDAS Expert Engineer Webinar Series Case Study ... Academy...MIDAS AU Expert Engineer Webinar...

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