62394728 Cable Stayed Bridges

MBP

COCHRANE and OTHER CABLE-STAYED BRIDGES ANALYZED BY MBP

COCHRANE and OTHER CABLE-STAYED BRIDGES ANALYZED BY MBP

Presented byFrank McDonough & Kay Bakhtar

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Frank McDonough & Kay Bakhtar

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SPAN1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 19 20 21 22 23 24 25 26 27 28 29 30 31 32

SPAN33

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11-13-06

Cable-Stayed Bridges, analyzed by MBP

Steubenville,OH and WVA

James River, Richmond, VA

Cochrane, ALA,

James River Bridge ($20 million delay claim)($20 million delay claim)

• VDOT Client• Precast Concrete Segments• Cast on shore and hauled

by Truck and Barge.• Segments lifted by custom-

built traveling deck-mounted cranes.

• Main Delay Issue: weights• Main Delay Issue: weightsof the segments and deflection of the cantilever.

• Other Issues: rebarOther Issues: rebarinterferences, DSCs, sole-source procurement of Materials.

MBP Team-members:

Frank Charlie Blake Mike P KayFrank, Charlie, Blake, Mike P, Kay…

Steubenville BridgeSteubenville Bridge– Client: SJGroves, contractor

– Segments: Structural steel with concrete deck

– Issues: Steel off-site fabrication delays

– Subcontractor lawsuit

– Settled in mid-TrialSettled in mid Trial

Cochrane Bridge

• Client: Harbert International, Birmingham, ALAClient: Harbert International, Birmingham, ALA• Claim/Mediation/Trial over delays, inefficiencies and LDs• Eight-year pause in MBP’s work between 1997 and 2005• Jury TrialJury Trial• Complex issues including Engineering of Balanced Cantilever• Successful outcome for Client

Key-words in Construction…“Wh t i P t t i i ?”“What is Post tensioning …?”

• A method of applying external force to pp y gload a structure: usually with high strength steel bars or cables often referred to as tendons.

• Extensively used in Concrete: multi-story buildings and Bridges.

• Also used heavy construction (tiebacks).y ( )

Post-tensioning ConcreteConcrete is strong in compression and weak in tension.

When loaded, a concrete beam will sag or deflect causing the bottom of the beam to elongate and crack.g

Tensile forces tend to pull apart the bottom of a beam as it bends.

Steel reinforcing – rebar - is embedded in concrete as tensile reinforcement to minimize/control cracking.g

Post Tensioning Concrete

• Tendons are used to take tensile loads

Post-tensioning Concrete • Rebar provides passive reinforcement . It carries load

when concrete deflects.

• Post-tensioning provides active reinforcement. The tendons are pre-loaded externally (with Hydraulic Jacks).

• Post-tensioning Advantages.– longer spans,– thinner slabs, – fewer beams, – greater flexibility in column layout.

• Two major types:– Steel Strands (Fressinet)

St l B (D id )– Steel Bars (Dywidag)

Post-tensioningStrand

Bars

The Cochrane Bridge Projectg j• Complete the project after termination of a

previous Contractor.previous Contractor.

• Two Contracts: Main Span & Approaches

• Main Span: mid-span and two back-spans are Cable StayedCable-Stayed

• Approaches: Box Girders cast-on-ground and pp glifted and cast in position. Lifting Equipment provided by Owner.

• Delays & inefficiencies on both contracts

Cochrane Bridge Layoutg y

The Main Spanp

• 1500 ft Main Span over Mobile River.• Three spans: 360, 780 and 360 ftp 360, 80 360• Cast-in-place concrete segments placed in

Balanced Cantilever procedurep• 96 Cable Stays

The Main Span

The Approaches

• Three five-span continuous sections each sideThree five span continuous sections each sideof main span. Typical spans 195 ft.

• 29 Piers each side and two abutments.

• Concrete Superstructure Girders Cast on the Ground cured Post-tensioned then Lifted intoGround, cured, Post tensioned, then Lifted intopermanent position (lifting equipment provided by ADOT).

Background• S.J. Groves was the original contractor

• Terminated for default when Main Span was 45% and• Terminated for default when Main Span was 45% andapproaches 55% complete

• ADOT re-bid completion of the project.

• Existing Structure and Temporary Equipment inspected• Existing Structure and Temporary Equipment inspectedby ADOT and turned over to Harbert, MBP Client.

• NTP to Harbert 7/19/89.

• Construction duration of each contract was 450 days• Construction duration of each contract was 450 days.

MBP Involvement1994 MBP t i d b S i & H lli th• 1994: MBP was retained by Spriggs & Hollingsworth(John Bond), Attorneys for Harbert to:– Analyze construction delays.– Provide expert opinion as to causation, responsibility

and quantification of Delays and Costs.

• 1997: Mediation in Atlanta (Buck Griffin) did not settle.

• 1997 to 2005: Litigation over right to sue State of Alabama; Harbert won.

• February 2005: MBP rehired by Doug Patton for trial preparation and expert testimony on schedule and costs.

• August 2005: Jury Trial. Favorable award.

The MBP TeamsThe MBP Teams

• Phase 1: 1994-1997Phase 1: 1994 1997Frank, Charlie, Mairav & Kay

• Phase 2: 2005GFrank, Kay, Ghas, Pam and Frankie

The Parties• Owner = State of Alabama DOT

• DOT Designer = Figg and Muller

DOT D i E t TYLi• DOT Design Expert= TYLin

• Contractor = Harbert International• Contractor = Harbert International

• Harbert Design Expert = Peter Taylor, Canadag p y ,

• Law Firms = Spriggs and Hollingsworth, Bradley Arant Rose and White, LLP

Delay Analysis MethodologyDelay Analysis Methodology

As-Planned vs. As-Built Schedule Analysis:y

Step 1: Verify As-Planned Schedule. Correct Any Absolute Errors,

Omissions.

Step 2: Prepare Detailed As-Built Schedule.

Step 3: Analyze Critical Path Delays by Comparison and Evaluation

of As-Planned and As-Built Performance.of As Planned and As Built Performance.

Analyze Delays and Concurrency with Detailed F t

As-Planned vs. As-BuiltSchedule AnalysisSchedule Analysis

Step 1

AS-PLANNED SCHEDULE

Foundations

Structure

InteriorInterior

Milestone 3

Milestone 2

COMPLETE

Milestone 1

COMPLETEFOUNDATION

21 Days Late

Step 2

COMPLETEPROJECT

56 Days Late

COMPLETESTRUCTURE

36 Days Late

McDonough Bolyard Peck Schedulegraphc

AS-BUILT SCHEDULE

Schedule AnalysisStep 1

AS-PLA N NED SCH EDU LE

Foundations

Step 1

Structure

InteriorInterior

Milestone 3

COMPLETE

Milestone 2

COMPLETESTRUCTURE

Milestone 1

COMPLETEFOUNDATION

21 Days Late

Step 2PROJECT

56 Days Late36 Days Late

Step 3 AS-BUILT SCHEDULE

3RESPONSIBILITY DAYS

OWNERCONTRACTOR

812

6 713 33

16

OTHER 73 4

A n a l y z e D e l a y s

T O T A L 56

OTHER 73 4

McDonough Bolyard Peck Schedulegraphc

IssuesMAIN SPAN:

– Tie-down Drilling Delays Due to AHD’s Stoppagesg y pp g– Formwork adjustments Due to AHD Pier Segment

Defects– Traveler advance: Rear Anchorage Delay Due to g y

Reinforcement Interferences – AHD Elevation Error – Unnecessary Balance of Stay StressingUnnecessary Balance of Stay Stressing– Inadequate Stay Pipe Delays to Cable Stay Stressing– Added Sandblasting Vertical Face of Segments

Weather Delays– Weather Delays– AHD Pylon Change – Added Deck Grinding – Strike Delays – Ferry Damage

IssuesIssuesAPPROACHES:APPROACHES:

– Latent Defects in Existing Concrete– Latent Defects in Existing ConcreteStructure

– Equipment BreakdownsEquipment Breakdowns– Lifting Restriction – Added Deck GrindingAdded Deck Grinding– Weather Delays – Strike Delays– Strike Delays

Main Span: Summary of Delays Graphic

Approaches: Summary of Delays Graphic

Cochrane Bridge Construction Video 1:Video 1:

Aerial Views

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 2:Video 2:

Construction Sequence

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 3:Video 3:

Balanced v. Out of Balanced

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 4:Video 4:

Main Span Construction

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 5:Video 5:Traveler

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 6:Video 6:

On-Site Traveler

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 7:Sand Blasting, Rebar/Form/Pour DiaphragmSand Blasting, Rebar/Form/Pour Diaphragm

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 8:Stressing JackStressing Jack

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 9: RebarRebar

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 10: Stress Longitudinal Dywidag Bars10: Stress Longitudinal Dywidag Bars

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 11: Stay Main Body Connectors11: Stay Main Body Connectors

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 12:Installing Strandg S

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 13:Stressing Strandsg

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 14: Grouting14: Grouting

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 15: Approach Span Lifting Operation15: Approach Span Lifting Operation

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 16:Lifting Cableg

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 17:Deck ConnectorDeck Connector

N e x t S l i d e ( c l i c k t w i c e )

Cochrane Bridge Construction Video 18:Lifting CableLifting Cable

N e x t S l i d e ( c l i c k t w i c e )

Challenges for MBP Team

• Project Records in four locations: DC, Mobile, Birmingham MBPBirmingham, MBP.

• Stop, wait, and gop, , g

• Client changes in personnel

• Understanding the Design Issues

• Project Controls Issues: CPM, dailies

J T i l i t t d b H i K t i• Jury Trial interrupted by Hurricane Katrina