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Monitoring a Prestressed ConcreteBox-Beam Bridge for Superloads
Osman Hag-ElsafiOsman Hag-Elsafi
Jonathan KuninJonathan Kunin
Structures ResearchStructures Research
Transportation Research and Development BureauTransportation Research and Development Bureau
New York State Department of TransportationNew York State Department of Transportation
Overview Route 9W over Coeymans Creek BridgeRoute 9W over Coeymans Creek Bridge Superloads and Crossing PatternsSuperloads and Crossing Patterns Instrumentation planInstrumentation plan Superloads Monitoring and Data AcquisitionSuperloads Monitoring and Data Acquisition Data Analysis and ResultsData Analysis and Results ConclusionsConclusions
Route 9W over Coeymans Creek
Route 9W over Coeymans Creek Built in 1985Built in 1985 AADT of 26,000 vehiclesAADT of 26,000 vehicles 107-ft long107-ft long 11 adjacent prestressed concrete box beams11 adjacent prestressed concrete box beams
– 8, 4-ft wide beams8, 4-ft wide beams– 3, 3-ft wide beams (center beams)3, 3-ft wide beams (center beams)– Integral abutmentsIntegral abutments– Composite concrete deckComposite concrete deck
Route 9W over Coeymans Creek Boiler modules for a power plantBoiler modules for a power plant
– Varying weights (83 to 253 kips)Varying weights (83 to 253 kips)– Loaded on 16-axle trailers (123 kips)Loaded on 16-axle trailers (123 kips)
Loads pulled by 1 or 2 tractor unitsLoads pulled by 1 or 2 tractor units– 4 axle tractors (46 kips)4 axle tractors (46 kips)– 3 axle tractors (77 kips)3 axle tractors (77 kips)
Gross loads of up to 453 kipsGross loads of up to 453 kips
Route 9W over Coeymans Creek
Superload
Route 9W over Coeymans Creek
[email protected] m7.0 m 4.2 m
C.L Bridge
d1=3.7 md2=1.3 md3=1.4 m
d1 d1d2 d2 d3d3
Travel direction
Locked wheels (Typ.)
Power units
Trai ler unit
Crabbed Crossing Patterns
Route 9W over Coeymans Creek
15 @1. 4 m4.2 m
C .L. Bridge
d 1=4.4 m d 2 =1.6 m
Tra ve l di re ct ion
Unlocked whee ls (T yp.)Power uni t
Tra il er uni t
d 1 d 2
Diagonal Crossing Pattern
Route 9W over Coeymans Creek
Project Objectives:Project Objectives:– Measure stress levels in the beamsMeasure stress levels in the beams– Evaluate the two crossing patternsEvaluate the two crossing patterns– Study the integral abutment structureStudy the integral abutment structure
Route 9W over Coeymans Creek
C.L. Bridge
North
1110987654321
C.L. Bridge C.L. Beam 8
6.25 m
Beam 11
11
C.L. Beam 8
3 0.91-m wide beams 4 1.22-m wide beams4 1.22-m wide beams
32.61 m
5.1 m1 m 4.2 m 0.8 m
1.22 m
Section A-A
: Gage location
Bridge Plan
C.L. Beam 11
Composite deck
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 conductedAdditional load tests were conducted– Known weights and configurationsKnown weights and configurations– Investigate transverse load distributionInvestigate transverse load distribution– Validate a computer programValidate a computer program
BRADD II was used for analysisBRADD 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 Measured stress levels indicated that the beams did not crackdid not crack
Good transverse load distribution confirmed Good transverse load distribution confirmed with load testingwith load testing
No clear advantage to crabbing over diagonal No clear advantage to crabbing over diagonal crossing patterncrossing pattern– Load distribution patterns were similarLoad distribution patterns were similar
Route 9W over Coeymans CreekConclusions
The bridge acted somewhere between The bridge acted somewhere between completely fixed and simply supported completely fixed and simply supported – Live load moments ranged from 52% to Live load moments ranged from 52% to
66% of simply supported analysis 66% of simply supported analysis Conclusions are specific to this bridge and Conclusions are specific to this bridge and
may not be generalized for all structuresmay not be generalized for all structures
Contact Information
Osman Hag-Elsafi, Ph.D.,P.E.Osman Hag-Elsafi, Ph.D.,P.E.Acting Head of Structures ResearchActing Head of Structures Research
Transportation Research & Development BureauTransportation Research & Development BureauNew York State Dept. of TransportationNew York State Dept. of Transportation
1220 Washington Avenue1220 Washington AvenueAlbany, NY 12232-0869Albany, NY 12232-0869
Tel: (518) 457-5826Tel: (518) [email protected]@dot.state.ny.us