Composite Bridge Decking, Final Project Report
TABLE OF CONTENTS
- Numerical Modeling and Validation
- Deck Fabrication
- Deck Installation
- Conclusions and Lessons Learned
- Appendix A: Lessons Learned–Allegany County Perspective
- Appendix B: Report on Finite Element Analysis
- Appendix C: Repport on Field Load Test
- Appendix D: Specification for Composite Bridge Decking
- Appendix E: Drawings for Proof-of-Concept Bridge
List of Figures
- Figure 1. Photo. Pultruded tube.
- Figure 2. Diagram. Dimensions of tube cross-section.
- Figure 3. Diagram. Fiber architecture of the tube.
- Figure 4. Photo. Pultruded tube subcomponent consisting of E-glass and vinyl ester resin.
- Figure 5. Photo. Tube subcomponents are bonded together with adhesive to form a panel.
- Figure 6. Photo. Panel ends are capped and radii between tubes filled with thixotropic resin.
- Figure 7. Photo. The panel is wrapped in glass fiber in preparation for infusion with vinyl ester resin.
- Figure 8. Photo. Infusion of resin for outer wrap using vacuum-assisted resin transfer molding (VARTM) method.
- Figure 9. Photo. Infused deck panel is stripped and inspected for thorough wet-out.
- Figure 10. Photo. Adhesive and stone applied for course 1 of the wearing surface. Note the black prefabricated railing post pad and stone bonded to the sloped surface.
- Figure 11. Photo. Panels labeled for shipping to the job site.
- Figure 12. Photo. Stringline girders to determine if haunch corrections are needed. Note that the A588 stringer has replaced one that was corroded due to the previous open grating.
- Figure 13. Photo. Place prefabricated haunches (black epoxy-coated red oak).
- Figure 14. Photo. Situate crane and pick panels with two slings. Approximate panel weight is 20 psf, including wearing surface course 1. On this project, a panel weighed approximately 1,800 lb.
- Figure 15. Photo. Place panels on top of prefabricated haunches. Note studs that make a fixed connection between the deck and stringers at midspan.
- Figure 16. Photo. Place prefabricated deck panels so transverse field joints are as tight as possible, making fine adjustments with a steel road bar.
- Figure 17. Photo. Secure panels with stainless steel clips and expansion bolts. Expansion bolt is shown. Figure 18. Photo. Secure panels with stainless steel clips and expansion bolts. Clip is shown.
- Figure 19. Photo. Installed clip. Methacrylate adhesive can be used to fill voids above or below prefabricated haunches to ensure uniform bearing. This was done on 9/4/2012.
- Figure 20. Photo. Install fixed connection between deck and steel stringers per plan.
- Figure 21. Photo. Install 5/8-inch foam backer rod at bottom of field joints.
- Figure 22. Photo. Install transverse rebar and epoxy grout in field joints. Thirty-six-inch #3 stainless rebar provides a positive tie across the centerline joint.
- Figure 23. Photo. Embed clean, dry, angular aggregate on the surface of the epoxy-grout field joints.
- Figure 24. Photo. Mix epoxy grout for deck nosing at bridge joints.
- Figure 25. Photo. Install 1-inch foam backer board at bridge joint at each end of the deck to square up the end of the deck. Install epoxy grout in deck nosing at joints.
- Figure 26. Photo. Apply resin for second course of wearing surface.
- Figure 27. Photo. Broadcast crushed stone for second course of wearing surface.
- Figure 28. Photo. Spread crushed stone aggregate for second course of wearing surface. Then install 1-inch foam backer rod at the bottom of the begin and end bridge joints (not pictured).
- Figure 29. Photo. Install two-part pourable joint material per manufacturer’s instructions.
- Figure 30. Photo. Align prefabricated high-density polyethylene pad for bridge railing posts.
- Figure 31. Photo. Install bridge railing posts, rails, and approach railing.
- Figure 32. Photo. Load test to determine the load capacity of the bridge; not normally needed to assess the deck.
- Figure 33. Diagram. 3D view.
- Figure 34. Diagram. Half of FRP deck (7 panels with 11 cells and 1 panel with 8 cells).
- Figure 35. Diagram. Cross-section of a part of the FRP deck.
- Figure 36. Diagram. Girders.
- Figure 37. Diagram. Cross-section of the girders.
- Figure 38. Diagram. Loading and boundary conditions.
- Figure 39. Diagram. Deflection (service load), small footprint.
- Figure 40. Diagram. Mesh.
- Figure 41. Diagram. Tsai-Hill Index (LRFD), small footprint.
- Figure 42. Photos and diagrams. 7600 tri-axle dump trucks used for live-load test.
- Figure 43. Diagrams and photos. Illustration of load path A.
- Figure 44. Diagrams and photos. Illustration of load path B.
- Figure 45. Diagrams and photos. Illustration of load path C.
- Figure 46. Diagrams and photos. Illustration of load path D.
- Figure 47. Photos. Field equipment setup.
- Figure 48. Diagrams. Repetition 1 strain gage locations.
- Figure 49. Diagrams. Repetition 2 strain gage locations.
- Figure 50. Diagrams. String pot locations.
- Figure 51. Graph. SG 5 data from test 1_63_CN.
- Figure 52. Graph. Test 1_63_CN, SG 7 and SG 8 results vs. time.
- Figure 53. Graph. Dynamic test results, string pots 2 and 5.
- Figure 54. Diagram. Proof-of-concept installation drawings—cover sheet.
- Figure 55. Diagram. Plan view.
- Figure 56. Diagram. Panel layout.
- Figure 57. Diagram. Existing cross-section.
- Figure 58. Diagram. Proposed cross-section.
- Figure 59. Diagram. Fascia and details.
- Figure 60. Diagram. Longitudinal section and details.
- Figure 61. Diagram. Panel cross-section and details.
- Figure 62. Diagram. Haunch plan and sections.
List of Tables
- Table 1. Project tasks
- Table 2. Ply details for horizontal walls of pultruded tube
- Table 3. Ply details for inclined walls of pultruded tube
- Table 4. Material properties of composite material
- Table 5. Material properties of polymer grout
- Table 6. Material properties (composite)
- Table 7. Material properties (concrete)
- Table 8. Material properties (steel)
- Table 9. Service load deflection and failure index with concrete, small footprint (6 by 7 in2), with lane load
- Table 10. Service load deflection and failure index with graphite, small footprint (6 by 7 in2), no lane load
- Table 11. Service load deflection and failure index with graphite, large footprint (10 by 20 in2), no lane load
- Table 12. State of stress in the critical composite element (SL loading), small footprint, no lane load
- Table 13. State of stress in the critical composite element (LRFD loading), small footprint, no lane load.
- Table 14. State of stress in the critical composite element (SL loading), large footprint, no lane load.
- Table 15. State of stress in the critical composite element (LRFD loading), large footprint, no lane load.
- Table 16. 7600 tri-axle dump truck axle spacings
- Table 17. Strain gage locations and orientations
- Table 18. String pot locations and descriptions
- Table 19. Test names and conditions
- Table 20. Maximum deformations at bearing locations
- Table 21. Maximum midspan FRP deck deformations (repetition 1)
- Table 22. SG 7 and SG 8 response for load case 1_63_A
- Table 23. Strains in all girders for critical load cases
- Table 24. Maximum vertical displacements at midspan
- Table 25. Test 2_64_A
- Table 26. Test 2_64_B
- Table 27. Test 2_64_BN
- Table 28. Test 2_64_C
- Table 29. Test 2_64_CN
- Table 30. Test 2_643_D
|AASHTO||American Association of State Highway and Transportation Officials|
|CSM||Chopped strand mat|
|LRFD||Load and Resistance Factor Design|
|MSDS||Material safety data sheet|
|VARTM||Vacuum-assisted resin transfer molding|
This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document.
The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document.
Quality Assurance Statement
The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.
1. Report No.
2. Government Accession No.
3. Recipient's Catalog No.
4. Title and Subtitle
5. Report Date
6. Performing Organization Code
8. Performing Organization Report No.
9. Performing Organization Name and Address
10. Work Unit No. (TRAIS)
11. Contract or Grant No.
12. Sponsoring Agency Name and Address
13. Type of Report and Period Covered
14. Sponsoring Agency Code
15. Supplementary Notes
The process used to fabricate deck panels was improved by combining consistent-quality pultruded subcomponents with a vacuum-infused outer wrap. The strength and stiffness were first determined analytically using finite element methods, then validated independently with extensive full-scale laboratory testing. Details of the installation were demonstrated on a 40-foot-long bridge during August 2012. After a two-course wearing surface was applied, the bridge was instrumented and load tested to further refine the finite element model.
The numerical model was found to be a reliable and accurate representation of actual conditions, with predicted strains and deflections within 5 percent of what was measured in the field. With working stresses less than 25 percent of the material’s ultimate strength, a sudden failure of the deck is virtually impossible. Furthermore, panels purposely overloaded in the lab exhibited a pseudo-ductile behavior and had residual strength after failure. The 5-inch-thick composite deck carried two 35-ton test trucks during a field test, with a self-weight of about 20 psf. The lightweight deck helped improve the load rating of the bridge, which was a priority for the owner.
The end result of the project is a robust, high-quality deck suitable for many applications, including moveable bridges, historic trusses, and posted bridges. Because the initial material cost is higher than conventional alternatives, future use may be restricted to situations where the rapid installation offsets the cost of maintenance and protection of traffic, or where the light weight is especially important, such as on moveable, deteriorated or historic structures. In any case, the total life cycle cost is competitive because of the material's innate resistance to deterioration (such as corrosion and fatigue).
17. Key Words
18. Distribution Statement
19. Security Classification (of this report)
20. Security Classification (of this page)
21. No. of Pages
|Symbol||When You Know||Multiply By||To Find||Symbol|
|in2||square inches||645.2||square millimeters||mm2|
|ft2||square feet||0.093||square meters||m2|
|yd2||square yard||0.836||square meters||m2|
|mi2||square miles||2.59||square kilometers||km2|
|fl oz||fluid ounces||29.57||milliliters||mL|
|ft3||cubic feet||0.028||cubic meters||m3|
|yd3||cubic yards||0.765||cubic meters||m3|
|NOTE: volumes greater than 1000 L shall be shown in m3|
|T||short tons (2000 lb)||0.907||megagrams (or "metric ton")||Mg (or "t")|
|Temperature (exact degrees)|
|Force and Pressure or Stress|
|lbf/in2||poundforce per square inch||6.89||kilopascals||kPa|