1. 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

2. Overview Route 9W over Coeymans Creek Bridge Route 9W over Coeymans Creek Bridge Superloads and Crossing Patterns Superloads and Crossing Patterns Instrumentation plan Instrumentation plan Superloads Monitoring and Data Acquisition Superloads Monitoring and Data Acquisition Data Analysis and Results Data Analysis and Results Conclusions Conclusions

3. Route 9W over Coeymans Creek

4. Built in 1985 Built in 1985 AADT of 26,000 vehicles AADT of 26,000 vehicles 107-ft long 107-ft long 11 adjacent prestressed concrete box beams 11 adjacent prestressed concrete box beams –8, 4-ft wide beams –3, 3-ft wide beams (center beams) –Integral abutments –Composite concrete deck

5. Route 9W over Coeymans Creek Boiler modules for a power plant 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 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 Gross loads of up to 453 kips

6. Route 9W over Coeymans Creek Superload

7. Route 9W over Coeymans Creek Crabbed Crossing Patterns

8. Route 9W over Coeymans Creek Diagonal Crossing Pattern

9. Route 9W over Coeymans Creek Project Objectives: Project Objectives: –Measure stress levels in the beams –Evaluate the two crossing patterns –Study the integral abutment structure

10. Route 9W over Coeymans Creek Instrumentation Plan

11. Route 9W over Coeymans Creek 453 kip Superload: Crossed Crabbed Midspan Strains

12. Route 9W over Coeymans Creek 281 kip Superload : Crossed Diagonally Midspan Strains

13. Route 9W over Coeymans Creek 453 kip Superload : Crossed Crabbed Distribution Factors

14. Route 9W over Coeymans Creek 281 kip Superload: Crossed Diagonally Distribution Factors

15. Route 9W over Coeymans Creek Distribution Factors Comparison

16. Route 9W over Coeymans Creek 453 kip Superload: Crossed Crabbed Beam 8 Strains

17. Route 9W over Coeymans Creek 281 kip Superload: Crossed Diagonally Beam 11 Strains

18. Route 9W over Coeymans Creek Additional load tests were conducted Additional load tests were conducted –Known weights and configurations –Investigate transverse load distribution –Validate a computer program BRADD II was used for analysis BRADD II was used for analysis

19. Route 9W over Coeymans Creek Load Test Trucks: Crossed Straight Midspan Strains

20. Route 9W over Coeymans Creek Load Test Trucks: Crossed Straight Distribution Factors

21. Route 9W over Coeymans Creek Effect of the Integral Ends on Moment

22. Route 9W over Coeymans Creek Moment Capacity Analysis

23. Route 9W over Coeymans Creek Conclusions Measured stress levels indicated that the beams did not crack Measured stress levels indicated that the beams did not crack Good transverse load distribution confirmed with load testing Good transverse load distribution confirmed with load testing No clear advantage to crabbing over diagonal crossing pattern No clear advantage to crabbing over diagonal crossing pattern –Load distribution patterns were similar

24. Route 9W over Coeymans Creek Conclusions The bridge acted somewhere between completely fixed and simply supported 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 Conclusions are specific to this bridge and may not be generalized for all structures

25. 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