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Monitoring a Prestressed Concrete Box-Beam Bridge for Superloads. Osman Hag-Elsafi Jonathan Kunin Structures Research Transportation Research and Development Bureau New York State Department of Transportation. Overview. Route 9W over Coeymans Creek Bridge Superloads and Crossing Patterns
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Monitoring a Prestressed ConcreteBox-Beam Bridge for Superloads Osman Hag-Elsafi Jonathan Kunin Structures Research Transportation Research and Development Bureau New York State Department of Transportation
Overview • Route 9W over Coeymans Creek Bridge • Superloads and Crossing Patterns • Instrumentation plan • Superloads Monitoring and Data Acquisition • Data Analysis and Results • Conclusions
Route 9W over Coeymans Creek • Built in 1985 • AADT of 26,000 vehicles • 107-ft long • 11 adjacent prestressed concrete box beams • 8, 4-ft wide beams • 3, 3-ft wide beams (center beams) • Integral abutments • Composite concrete deck
Route 9W over Coeymans Creek • Boiler modules for a power plant • Varying weights (83 to 253 kips) • Loaded on 16-axle trailers (123 kips) • Loads pulled by 1 or 2 tractor units • 4 axle tractors (46 kips) • 3 axle tractors (77 kips) • Gross loads of up to 453 kips
Route 9W over Coeymans Creek Superload
Route 9W over Coeymans Creek CrabbedCrossing Patterns
Route 9W over Coeymans Creek Diagonal Crossing Pattern
Route 9W over Coeymans Creek • Project Objectives: • Measure stress levels in the beams • Evaluate the two crossing patterns • Study the integral abutment structure
Route 9W over Coeymans Creek Instrumentation Plan
Route 9W over Coeymans Creek 453 kip Superload: Crossed Crabbed Midspan Strains
Route 9W over Coeymans Creek 281 kip Superload : Crossed Diagonally Midspan Strains
Route 9W over Coeymans Creek 453 kip Superload: Crossed Crabbed Distribution Factors
Route 9W over Coeymans Creek 281 kip Superload: Crossed Diagonally Distribution Factors
Route 9W over Coeymans Creek Distribution Factors Comparison
Route 9W over Coeymans Creek 453 kip Superload: Crossed Crabbed Beam 8 Strains
Route 9W over Coeymans Creek 281 kip Superload: Crossed Diagonally Beam 11 Strains
Route 9W over Coeymans Creek • Additional load tests were conducted • Known weights and configurations • Investigate transverse load distribution • Validate a computer program • BRADD II was used for analysis
Route 9W over Coeymans Creek Load Test Trucks: Crossed Straight Midspan Strains
Route 9W over Coeymans Creek Load Test Trucks: Crossed Straight Distribution Factors
Route 9W over Coeymans Creek Effect of the Integral Ends on Moment
Route 9W over Coeymans Creek Moment Capacity Analysis
Route 9W over Coeymans Creek Conclusions • Measured stress levels indicated that the beams did not crack • Good transverse load distribution confirmed with load testing • No clear advantage to crabbing over diagonal crossing pattern • Load distribution patterns were similar
Route 9W over Coeymans CreekConclusions • The bridge acted somewhere between completely fixed and simply supported • Live load moments ranged from 52% to 66% of simply supported analysis • Conclusions are specific to this bridge and may not be generalized for all structures
Contact Information Osman Hag-Elsafi, Ph.D.,P.E. Acting Head of Structures Research Transportation Research & Development Bureau New York State Dept. of Transportation 1220 Washington Avenue Albany, NY 12232-0869 Tel: (518) 457-5826 ohag-elsafi@dot.state.ny.us