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Composite Bridge Decking: Phase I Design Report


Publication No. FHWA HIF-13-030
January 2013

Table of Contents

  1. Introduction
  2. Testing
  3. After-Test Review
  4. Conclusions

List of Figures

Figure 1. Photo. The pultruded tube subcomponent consisting of E-glass and vinyl ester resin.
Figure 2. Photo. Tube subcomponents are bonded together with adhesive to form a panel.
Figure 3. Photo. Panel ends are capped and radii between tubes filled with thixotropic resin.
Figure 4. Photo. The panel is wrapped in glass fiber in preparation for infusion with vinyl ester resin.
Figure 5. Photo. Resin is infused for the outer wrap using a vacuum-assisted resin transfer molding (VARTM) method.
Figure 6. Photo. Each infused deck panel is stripped and inspected to ensure that fibers have been thoroughly
wet-out with resin.
Figure 7. Photo. Adhesive and stone are applied for course 1 of the wearing surface.
Figure 8. Diagram. Geometry of ice shield profile with single cavit.
Figure 9. Graph. Constituent content of test laminates as a percentage of total laminate thickness.
Figure 10. Diagram. Fiber directions for in-plane shear strength testing.
Figure 11. Diagram. Structure of double bias laminate.
Figure 12. Diagram. Pultruded combination tube.
Figure 13. Diagram. Laminate construction for pultruded combination tube.
Figure 14. Diagram. Pultruded FRP combination tube
Figure 15. Diagram. FRP tube cross section.
Figure 16. Diagram. Grout configurations
Figure 17. Photo and diagram. Testing setup.
Figure 18. Photos. Load cells used for FRP testing.
Figure 19. Diagram. Strain gage locations for the FRP tube specimen #30
Figure 20. Graphs. Load-deflection elastic response of FRP tubes with no grout (left);
Load-deflection response up to failure (tubes #30 and #38) (right)
Figure 21. Graph. Load-strain response of FRP tube #30 (no grout, WSU).
Figure 22. Photos. Failure modes of FRP tubes with no grout.
Figure 23. Graph. Load-deflection behavior up to failure for grouted FRP tubes
Figure 24. Graph. Load-deflection curve (up to 2,500 lb) of specimens #56, 57, and #31.
Figure 25. Graphs. Load-strain responses of grouted FRP tubes.
Figure 26. Photos. Photographs of failure modes of grouted FRP tubes
Figure 27. Photos. Cementitious grout slipping at the end of FRP tube #60
Figure 28. Photos. Cross sections of grouted tubes near midspan, after failure.
Figure 29. Specifications with photos. Manufacturing details of panels without grout.
Figure 30. Diagram. Grout configurations.
Figure 31. Photos and diagrams. FRP panel test setup.
Figure 32. Diagrams. Strain gage location for panel #4.
Figure 33. Diagrams. Strain gage location for panel #3 (tested to failure)
Figure 34. Graphs. Load-deflection response of FRP panels with no grout.
Figure 35. Graphs. Load-strain response of FRP panels with no grout.
Figure 36. Photos. Failure sequence of FRP panel #3 (no grout).
Figure 37. Photos and diagrams. Details of cut sections from panel #3.
Figure 38. Graphs. Load-deflection response of FRP grouted panels.
Figure 39. Diagrams. Strain gage location for panel #7.
Figure 40. Diagrams. Strain gage location for panel #10.
Figure 41. Graphs. Load-strain response of FRP panel #7-CA.
Figure 42. Graph. Load-strain plot of FRP panel #10-EA.
Figure 43. Graph. Load-strain (top & bottom) FRP panels.
Figure 44. Diagrams. Tested load footprints.
Figure 45. Diagrams. Test setup used to evaluate footprint effect.
Figure 46. Photos. Test setup details.
Figure 47. Graphs. Load-deflection responses of the two footprint tests.
Figure 48. Specifications with photo. Manufacturing details of tested panel.
Figure 49. Photo. FRP panel (WSD).
Figure 50. Diagram. Cross section dimensions of the FRP panel tested in fatigue
Figure 51. Photos and diagram. Fatigue test setup.
Figure 52. Graphs. Stiffness ratios as function of the number of fatigue load cycles (left);
temporary change in stiffness between 500,000 and 650,000 cycles (right).
Figure 53. Diagrams and photo. Location of wearing surfaces: applied to top and bottom of deck panel to assess performance in compression and tension.
Figure 54. Graph. Load-deflection behavior at different fatigue cycles.
Figure 55. Graph. Stiffness change during daytime.
Figure 56. Photos. Bottom wearing surface before and after 500,000 cycles fatigue load.
Figure 57. Photos. Top wearing surface before and after 350,000 cycles fatigue load.
Figure 58. Diagrams. Strain gage position.
Figure 59. Graph. Load-strain behavior (SG1).
Figure 60. Graph. Load-strain behavior (SG4).
Figure 61. Graph. Load-strain behavior (SG3).
Figure 62. Graph. Load-strain behavior (SG5).
Figure 63. Graph. Load-strain behavior (SG2).
Figure 64 Photo. Panel-to-panel field joint.
Figure 65. Diagram. Cross section dimensions.
Figure 66. Photos and diagrams. End panel connection test setup.
Figure 67. Photo. Crack at load of 7 kips.
Figure 68. Photo. Crack at maximum load of 14.7 kips.
Figure 69. Photo. Failure of the specimen (11.8 kips).
Figure 70. Graph. Load-deflection behavior.
Figure 71. Graph. Net specimen displacement.
Figure 72. Graph. Load-strain behavior of the epoxy key.
Figure 73. Photos. The two failed surfaces.
Figure 74. Diagram. Sketch of the crack line.
Figure 75. Photos and sketch. Railing post specimen.
Figure 76. Photo and diagrams. Railing post test setup.
Figure 77. Photo and diagram. Detailing of steel beam-structural frame connection.
Figure 78. Photos and diagrams. Location of transducers used during the test.
Figure 79. Graph. Load-displacement behavior of railing post end (string pot 2).
Figure 80. Photos. Failure mode of the railing post-FRP deck panel connection. .
Figure 81. Graph and photo. Vertical displacement of the railing post, Test 1.7
Figure 82. Diagram. Railing post connection (deformed shape, not to scale).
Figure 83. Photos. HDPE deformation at different loading levels, Test 2.
Figure 84. Graph. Horizontal deflection (x-direction), Test 2.
Figure 85. Graph. Vertical displacement (y-direction), Test 2.
Figure 86. Graph. String pot 4 movement, Test 2.
Figure 87. Diagram and photos. Expansion bolt connection.
Figure 88. Diagram and photos. Expansion bolt connection.
Figure 89. Photos. FRP specimen used for pull-off tests.
Figure 90. Photos. Dollies mounted to two test areas.
Figure 91. Photos. Failure surfaces of aggregate to adhesive pull-off tests (dollies 4, 5, and 6)
Figure 92. Photos. Failure surfaces of adhesive to FRP pull-off tests (dollies 7, 8, and 9)
Figure 93. Photo. Test panel mounted on top of fire chamber.
Figure 94. Photo. Support beams spaced at 2 feet.
Figure 95. Photo. 1,600-lb water tank used as concentrated load.
Figure 96. Photos. Placement of thermocouples on the test panel.
Figure 97. Photo. The test panel just after the test stopped.
Note that the top surface kept cooler and ended up with little deterioration.
Figure 98. Photo. Specimen immediately after the test. Note the extent of damage on the bottom.
Figure 99. Photo. Close-up of the open end of the panel after the test.
Figure 100. Photo. The glass fiber on the bottom has frayed due to burn-off of the resin matrix.

List of Tables

Table 1. Tube testing
Table 2. Test methods used in characterization
Table 3. Comparison of fiber architectures
Table 4. Comparison of laminate properties
Table 5. Suggested design values
Table 6. Material properties for the definition of a unidirectional lamina
Table 7. Test methods used in characterization
Table 8. Test laminates for characterization of lamina properties
Table 9. Summary of physical test data for laminate samples
Table 10. Suggested lamina design values for ply based design and analysis
Table 11. Predicted properties of pultruded tube.
Table 12. Ply details for horizontal walls of pultruded tube.
Table 13. Ply details for vertical walls of pultruded tube.
Table 14. Areal reinforcement weights (oz/yd2) of potential tube laminates.
Table 15. Test methods used in characterization.
Table 16. Summary of physical test data for tube laminate samples.
Table 17. Summary of physical test data from outer wrap laminate samples.
Table 18. Published grout properties.
Table 19. Results of grout testing.
Table 20 Relative merits of grouts for the application (i.e., fill material).
Table 21. Dimensions and thicknesses of FRP tubes (no grout).
Table 22. Details of FRP grouted tubes.
Table 23. Test program-FRP tubes no grout.
Table 24. Test program-grouted FRP tubes.
Table 25. Details of panels.
Table 26. Test program-FRP panel without grout.
Table 27. Test program-grouted FRP panels.
Table 28. Flexure stiffness as function of increasing number of fatigue cycles
Table 29. Load-displacement data for string pot 2.
Table 30. Test 2 HDPE pad deformation.
Table 31. Pull-off test results.
Table 32. Details of thermocouple placement.
Table 33. Deflection measurements.

List of Acronyms and Abbreviations
AASHTO American Association of State Highway and Transportation Officials
BIN Bridge Identification Number
CSM Chopped Strand Mat
DOT Department of Transportation
DOTD Department of Transportation and Development
FHWA Federal Highway Administration
FRP Fiber-Reinforced Polymer
HDPE High-Density Polyethylene
LRFD Load and Resistance Factor Design
LVDT Linear Variable Differential Transformer
VARTM Vacuum-Assisted Resin Transfer Molding
WSD Wide Side Down
WSU Wide Side Up


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
Composite Bridge Decking: Phase I Design Report
5. Report Date
September 2012
6. Performing Organization Code
7. Author(s)
J. S. O'Connor
8. Performing Organization Report No.
9. Performing Organization Name and Address
BridgeComposites, LLC
121 Upper Bennett St.
Hornell, NY 14843-1451
10. Work Unit No. (TRAIS)
11. Contract or Grant No.
12. Sponsoring Agency Name and Address
Federal Highway Administration
Highways for LIFE Program – HIHL-1
1200 New Jersey Avenue, SE
Washington, D.C. 20590
13. Type of Report and Period Covered
14. Sponsoring Agency Code
15. Supplementary Notes

16. Abstract
This report provides information about the materials, subcomponent shapes, and processes used to fabricate a lightweight decking system. It describes the design criteria and presents the results of physical testing done to validate the finite element analysis. Attention has been given to the structural panels used for decking, as well as to the design details that are critical to the successful deployment of the technology, such as field joint construction, and wearing surface installation.

The proposed design is a versatile hollow section that can be deployed in a variety of ways, depending on the design objectives and existing site conditions for a deck replacement project. The composite material provides sufficient strength to carry the factored American Association of State Highway and Transportation Officials (AASHTO) design load and, in cases where the supports are close together, is adequate for deflection control as well. Where steel stringers are spaced more than 3 feet on center, additional material is needed to increase the section’s stiffness. Testing has shown that fabrication with epoxy grout in selected cells of the hollow section will increase stiffness by 45 percent, although the grout adds 50 percent or more to the weight of the deck. In cases where it is very important to have a lightweight deck, deflection control can be achieved with additional fiber in the outer wrap. In this instance, the deck weighs approximately 16 psf prior to the application of a 4-psf wearing surface.

This report documents Phase I of the project. It is provided as an after-test review to get input from the project’s Technical Advisory Panel and other potential stakeholders.

17. Key Words
Composite deck, Fiber-reinforced polymer composite, FRP, bridge decking
18. Distribution Statement
No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161.
19. Security Classification (of this report)
20. Security Classification (of this page)
21. No. of Pages
22. Price

FORM DOT F 1700.7 (8-72)
Approximate Conversions to SI Units
Symbol When You Know Multiply By To Find Symbol
in inches 25.4 millimeters mm
ft feet 0.305 meters m
yd yards 0.914 meters m
mi miles 1.61 kilometers km
in2 square inches 645.2 square millimeters mm2
ft2 square feet 0.093 square meters m2
yd2 square yard 0.836 square meters m2
ac acres 0.405 hectares ha
mi2 square miles 2.59 square kilometers km2
fl oz fluid ounces 29.57 milliliters mL
gal gallons 3.785 liters L
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
oz ounces 28.35 grams g
lb pounds 0.454 kilograms kg
T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t")
Temperature (exact degrees)
°F Fahrenheit 5 (F-32)/9
or (F-32)/1.8
Celsius °C
fc foot-candles 10.76 lux lx
fl foot-Lamberts 3.426 candela/m2 cd/m2
Force and Pressure or Stress
lbf poundforce 4.45 newtons N
lbf/in2 poundforce per square inch 6.89 kilopascals kPa

*SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with
Section 4 of ASTM E380. (Revised March 2003)

Executive Summary

This report summarizes project Phase I, which involved the refinement of design, testing, and fabrication methods used to develop a lightweight, corrosion-resistant bridge deck. The deck can be used on any bridge, but it is particularly beneficial for moveable bridges because of its light weight. Fundamentally, the deck described in this report is the same as the design that was developed and tested between 2003 and 2009 for the New York State Department of Transportation (DOT) at the University at Buffalo, Department of Civil Structural and Environmental Engineering. After a careful assessment of various materials and available methods, refinements have been made to improve performance of the deck, facilitate its fabrication, and reduce its cost. Integral with the design and production improvements are the development of suitable construction details such as connections to the supporting steel, a durable wearing surface, and anchorages for railing posts.

The deck described in this report consists of glass fiber-reinforced polymer composite materials and grout when the stringer spacing necessitates additional stiffness.

After finite element analysis and validation by testing, it was found that the composite section was sufficiently stiff for use on the proof-of-concept bridge in Bolivar, NY, which has steel stringers spaced at 2 feet. The Pleasant Street Bridge over Little Genesee Creek (BIN 2215390) is 40 feet long and had a proposed width of 22 feet. Allegany County personnel started a rehabilitation project in August 2012, replaced the deck, and opened the bridge to traffic in September. The process used is similar to the installations envisioned for moveable bridges, which is the primary target of the Highways for LIFE project. A fixed-span bridge was selected to keep the scope contained enough that it could be done under the present project.

This report has been prepared to document the design and testing for review by the project Technical Advisory Panel, whose names and affiliations are shown below:

  • Ray Bottenberg, OR DOT.
  • Duane Daniels, Larson Design Group.
  • Jeremy Ferris, Allegany County, NY.
  • Paul Fossier, LA Department of Transportation and Development (DOTD).
  • Paul Liles, GA DOT.
  • George Patton, E.C. Driver, Inc.
  • William Potter, FL DOT.
  • Herbert Protin, HDR.
  • Tom Sheehan, NY State Thruway Authority, Canals Division.
  • Kevin Thompson, former Caltrans State Bridge Engineer.
  • Art Yannotti, former NY State Bridge Engineer.
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