Cable Stayed Bridges

MBP

COCHRANE and OTHER CABLE-STAYED BRIDGES ANALYZED BY MBP

Presented by Frank McDonough & Kay Bakhtar fw fw

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Cable-Stayed Bridges, analyzed by MBP

Steubenville, OH and WVA

James River, Richmond, VA

Cochrane,, ALA

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

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• MBP Team-members: Frank Charlie, Frank, Charlie Blake, Blake Mike P, P Kay… Kay

VDOT Client Precast Concrete Segments Cast on shore and hauled by Truck and Barge. Segments lifted by custombuilt traveling deck-mounted cranes. Main Delay Issue: weights of the segments and deflection of the cantilever. Other Issues: rebar interferences, DSCs, solesource procurement of Materials.

Steubenville Bridge – Client: SJGroves, contractor – Segments: Structural steel with concrete deck – Issues: Steel off-site fabrication delays – Subcontractor lawsuit – Settled in mid mid-Trial Trial

Cochrane Bridge

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

Key-words in Construction… “Wh t iis P “What Postt ttensioning i i …?” ?”

• A method of applying pp y g external force to load 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 heavyy construction ((tiebacks). )

Post-tensioning Concrete Concrete 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 g and crack.

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) – Steel St l Bars B (D (Dywidag) id )

Post-tensioning Strand

Bars

The Cochrane Bridge g Project j • Complete the project after termination of a previous Contractor. • Two Contracts: Main Span & Approaches • Main Span: mid-span and two back-spans are Cable Stayed Cable-Stayed • Approaches: pp Box Girders cast-on-ground g and lifted and cast in position. Lifting Equipment provided by Owner. • Delays & inefficiencies on both contracts

Cochrane Bridge g Layout y

The Main Span p

• 1500 ft Main Span over Mobile River. • Three spans: p 360, 780 80 and 360 ft • Cast-in-place concrete segments placed in p Balanced Cantilever procedure • 96 Cable Stays

The Main Span

The Approaches

• Three five-span five span continuous sections each side of main span. Typical spans 195 ft. • 29 Piers each side and two abutments. • Concrete Superstructure Girders Cast on the Ground cured, Ground, cured Post-tensioned Post tensioned, then Lifted into permanent position (lifting equipment provided by ADOT).

Background • S.J. Groves was the original contractor • Terminated for default when Main Span was 45% and approaches 55% complete • ADOT re-bid completion of the project. • Existing Structure and Temporary Equipment inspected by ADOT and turned over to Harbert, MBP Client. • NTP to Harbert 7/19/89. • Construction duration of each contract was 450 days days.

MBP Involvement • 1994 1994: MBP was retained t i d by b Spriggs S i & Hollingsworth H lli th (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 Teams • Phase 1: 1994 1994-1997 1997 Frank, Charlie, Mairav & Kay

• Phase 2: 2005 Frank, Kay, Ghas, G Pam and Frankie

The Parties • Owner = State of Alabama DOT • DOT Designer = Figg and Muller • DOT Design D i Expert= E t TYLin TYLi • Contractor = Harbert International • Harbert Design g Expert p = Peter Taylor, y , Canada • Law Firms = Spriggs and Hollingsworth, Bradley Arant Rose and White, LLP

Delay 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 As-Planned Planned and As-Built As Built Performance.

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Analyze Delays and Concurrency with Detailed t

As-Planned vs. As-Built Schedule Analysis Step

1 AS-PLANNED SCHEDULE Foundations

Structure

Milestone 1

Interior

COMPLETE FOUNDATION

21 Days Late

Milestone 2 COMPLETE STRUCTURE

Step

36 Days Late

2

Milestone 3 COMPLETE PROJECT

56 Days Late

AS-BUILT SCHEDULE McDonough Bolyard Peck Schedulegraph

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Schedule Analysis Step 1 A S -P L A N N E D S C H E D U L E Foundations Structure Interior

Milestone 1 COMPLETE FOUNDATION

Milestone 2

21 Days Late

Milestone 3

COMPLETE STRUCTURE

Step 2 Step 3

COMPLETE PROJECT

36 Days Late

56 Days Late

AS-BUILT SCHEDULE

A n a ly z e D e la y s 6

3

7 8

12 3

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RESPONSIBILITY

DAYS

CONTRACTOR OWNER

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OTHER

7

TO TAL

56

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McDonough Bolyard Peck Schedulegraph

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Issues MAIN SPAN: – Tie-down Drilling g Delays y Due to AHD’s Stoppages pp g – Formwork adjustments Due to AHD Pier Segment Defects – Traveler advance: Rear Anchorage g Delay y Due to Reinforcement Interferences – AHD Elevation Error – Unnecessary Balance of Stay Stressing – Inadequate Stay Pipe Delays to Cable Stay Stressing – Added Sandblasting Vertical Face of Segments – Weather Delays – AHD Pylon Change – Added Deck Grinding – Strike Delays – Ferry Damage

Issues APPROACHES: – Latent Defects in Existing Concrete Structure – Equipment Breakdowns – Lifting Restriction – Added Deck Grinding – Weather Delays – Strike Delays

Main Span: Summary of Delays Graphic

Approaches: Summary of Delays Graphic

Cochrane Bridge Construction Video 1: Aerial Views

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Cochrane Bridge Construction Video 2: Construction Sequence

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Cochrane Bridge Construction Video 3: Balanced v. Out of Balanced

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Cochrane Bridge Construction Video 4: Main Span Construction

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Cochrane Bridge Construction Video 5: Traveler

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Cochrane Bridge Construction Video 6: On-Site Traveler

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

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Cochrane Bridge Construction Video 8: Stressing Jack

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Cochrane Bridge Construction Video 9: Rebar

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Cochrane Bridge Construction Video 10: Stress Longitudinal Dywidag Bars

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Cochrane Bridge Construction Video 11: Stay Main Body Connectors

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Cochrane Bridge Construction Video 12: gS Strand Installing

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Cochrane Bridge Construction Video 13: g Strands Stressing

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Cochrane Bridge Construction Video 14: Grouting

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Cochrane Bridge Construction Video 15: Approach Span Lifting Operation

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Cochrane Bridge Construction Video 16: g Cable Lifting

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Cochrane Bridge Construction Video 17: Deck Connector

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Cochrane Bridge Construction Video 18: Lifting Cable

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Challenges for MBP Team • Project Records in four locations: DC, Mobile, Birmingham MBP. Birmingham, MBP • Stop, p, wait,, and go g • Client changes in personnel • Understanding the Design Issues • Project Controls Issues: CPM, dailies • Jury J T Trial i l interrupted i t t d by b Hurricane H i Katrina K ti