Monitoring a Prestressed Concrete Box-Beam Bridge for Superloads Osman Hag-Elsafi Jonathan Kunin Structures Research Transportation Research and Development.

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