62394728 cable stayed bridges
TRANSCRIPT
MBP
COCHRANE and OTHER CABLE-STAYED BRIDGES ANALYZED BY MBP
COCHRANE and OTHER CABLE-STAYED BRIDGES ANALYZED BY MBP
Presented byFrank McDonough & Kay Bakhtar
fw
fw
Frank McDonough & Kay Bakhtar
11-13-06 12 3 4 5 6 7 8 9 10 12 13 14 15 20 21 22 23 25 26 27 28 30 31 32 3317 18
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
11 16 19 24 29
fw fwfw
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