Phase I Design Report

Deliverable D4

Composite Bridge Decking

Publication No. FHWA-HIF-13-030

January 2013
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Technical Report Documentation Page

1. Report No.

FHWA-HIF-13-030

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.

DTFH61-09-RA-00006

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)

Unclassified

20. Security Classification (of this page)

Unclassified

21. No. of Pages

137

22. Price

FORM DOT F 1700.7 (8-72) REPRODUCTION OF COMPLETED PAGE AUTHORIZED
ii
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TABLE OF CONTENTS

1. INTRODUCTION......................................................................................................................1

2. TESTING....................................................................................................................................3

Testing Program...........................................................................................................................3

Materials.......................................................................................................................................3

Tube Subcomponents...................................................................................................................3

Structural Panels...........................................................................................................................4

Assembly......................................................................................................................................5

Details...........................................................................................................................................8

3. AFTER-TEST REVIEW...........................................................................................................9

4. CONCLUSIONS ......................................................................................................................11

APPENDIX A: DETERMINATION OF PRELIMINARY DESIGN PROPERTIES

APPENDIX B: DETERMINIATION OF LAMINA DESIGN PROPERTIES

APPENDIX C: EVALUATION OF “AS-TESTED” PROPERTIES OF FRP LAMINATES

APPENDIX D: GROUT SELECTION REPORT

APPENDIX E: REPORT ON TUBE TESTING

APPENDIX F: REPORT ON STRUCTURAL PANEL TESTING

APPENDIX G: PANEL SHEAR TEST

APPENDIX H: PANEL FATIGUE TEST

APPENDIX I: PANEL-TO-PANEL FIELD JOINT

APPENDIX J: BRIDGE RAILING POST ANCHRAGE PROOF TEST

APPENDIX K: WEARING SURFACE TEST

APPENDIX L: FIRE TEST REPORT

APPENDIX M: AFTER-TEST REVIEW PRESENTATION
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LIST OF FIGURES

Figure 1. Photo. The pultruded tube subcomponent consisting of E-glass and vinyl ester resin. .. 6

Figure 2. Photo. Tube subcomponents are bonded together with adhesive to form a panel. ......... 6

Figure 3. Photo. Panel ends are capped and radii between tubes filled with thixotropic resin....... 6

Figure 4. Photo. The panel is wrapped in glass fiber in preparation for infusion with vinyl ester 

resin........................................................................................................................................... 7

Figure 5. Photo. Resin is infused for the outer wrap using a vacuum-assisted resin transfer 

molding (VARTM) method. ..................................................................................................... 7

Figure 6. Photo. Each infused deck panel is stripped and inspected to ensure that fibers have been 

thoroughly wet-out with resin................................................................................................... 7

Figure 7. Photo. Adhesive and stone are applied for course 1 of the wearing surface................... 8

Figure 8. Diagram. Geometry of ice shield profile with single cavity. ........................................ 13

Figure 9. Graph. Constituent content of test laminates as a percentage of total laminate thickness.

................................................................................................................................................. 18

Figure 10. Diagram. Fiber directions for in-plane shear strength testing. .................................... 20

Figure 11. Diagram. Structure of double bias laminate................................................................ 29

Figure 12. Diagram. Pultruded combination tube......................................................................... 32

Figure 13. Diagram. Laminate construction for pultruded combination tube. ............................. 33

Figure 14. Diagram. Pultruded FRP combination tube................................................................. 42

Figure 15. Diagram. FRP tube cross section................................................................................. 48

Figure 16. Diagram. Grout configurations.................................................................................... 49

Figure 17. Photo and diagram. Testing setup. .............................................................................. 50

Figure 18. Photos. Load cells used for FRP testing...................................................................... 50

Figure 19. Diagram. Strain gage locations for the FRP tube specimen #30................................. 51

Figure 20. Graphs. Load-deflection elastic response of FRP tubes with no grout (left); Loaddeflection response up to failure (tubes #30 and #38) (right)................................................. 52

Figure 21. Graph. Load-strain response of FRP tube #30 (no grout, WSU). ............................... 52

Figure 22. Photos. Failure modes of FRP tubes with no grout..................................................... 52

Figure 23. Graph. Load-deflection behavior up to failure for grouted FRP tubes........................ 55

Figure 24. Graph. Load-deflection curve (up to 2,500 lb) of specimens #56, 57, and #31.......... 55

Figure 25. Graphs. Load-strain responses of grouted FRP tubes. ................................................ 56

Figure 26. Photos. Photographs of failure modes of grouted FRP tubes...................................... 57

Figure 27. Photos. Cementitious grout slipping at the end of FRP tube #60................................ 57
v

Figure 28. Photos. Cross sections of grouted tubes near midspan, after failure........................... 58

Figure 29. Specifications with photos. Manufacturing details of panels without grout. .............. 60

Figure 30. Diagram. Grout configurations.................................................................................... 61

Figure 31. Photos and diagrams. FRP panel test setup................................................................. 62

Figure 32. Diagrams. Strain gage location for panel #4. .............................................................. 63

Figure 33. Diagrams. Strain gage location for panel #3 (tested to failure)................................... 63

Figure 34. Graphs. Load-deflection response of FRP panels with no grout................................. 64

Figure 35. Graphs. Load-strain response of FRP panels with no grout........................................ 64

Figure 36. Photos. Failure sequence of FRP panel #3 (no grout)................................................. 65

Figure 37. Photos and diagrams. Details of cut sections from panel #3....................................... 66

Figure 38. Graphs. Load-deflection response of FRP grouted panels. ......................................... 68

Figure 39. Diagrams. Strain gage location for panel #7. .............................................................. 69

Figure 40. Diagrams. Strain gage location for panel #10. ............................................................ 69

Figure 41. Graphs. Load-strain response of FRP panel #7-CA. ................................................... 69

Figure 42. Graph. Load-strain plot of FRP panel #10-EA............................................................ 70

Figure 43. Graph. Load-strain (top & bottom) FRP panels. ......................................................... 70

Figure 44. Diagrams. Tested load footprints. ............................................................................... 72

Figure 45. Diagrams. Test setup used to evaluate footprint effect. .............................................. 73

Figure 46. Photos. Test setup details. ........................................................................................... 74

Figure 47. Graphs. Load-deflection responses of the two footprint tests. .................................... 74

Figure 48. Specifications with photo. Manufacturing details of tested panel............................... 76

Figure 49. Photo. FRP panel (WSD). ........................................................................................... 76

Figure 50. Diagram. Cross section dimensions of the FRP panel tested in fatigue...................... 76

Figure 51. Photos and diagram. Fatigue test setup. ...................................................................... 77

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). ......................... 78

Figure 53. Diagrams and photo. Location of wearing surfaces: applied to top and bottom of deck 

panel to assess performance in compression and tension. ...................................................... 79

Figure 54. Graph. Load-deflection behavior at different fatigue cycles....................................... 80

Figure 55. Graph. Stiffness change during daytime. .................................................................... 80

Figure 56. Photos. Bottom wearing surface before and after 500,000 cycles fatigue load. ......... 81

Figure 57. Photos. Top wearing surface before and after 350,000 cycles fatigue load ................ 81

Figure 58. Diagrams. Strain gage position.................................................................................... 81
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Figure 59. Graph. Load-strain behavior (SG1)............................................................................. 82

Figure 60. Graph. Load-strain behavior (SG4)............................................................................. 82

Figure 61. Graph. Load-strain behavior (SG3)............................................................................. 82

Figure 62. Graph. Load-strain behavior (SG5)............................................................................. 82

Figure 63. Graph. Load-strain behavior (SG2)............................................................................. 82

Figure 64. Photo. Panel-to-panel field joint.................................................................................. 84

Figure 65. Diagram. Cross section dimensions. ........................................................................... 84

Figure 66. Photos and diagrams. End panel connection test setup. .............................................. 85

Figure 67. Photo. Crack at load of 7 kips. .................................................................................... 86

Figure 68. Photo. Crack at maximum load of 14.7 kips. .............................................................. 86

Figure 69. Photo. Failure of the specimen (11.8 kips).................................................................. 87

Figure 70. Graph. Load-deflection behavior................................................................................. 87

Figure 71. Graph. Net specimen displacement. ............................................................................ 87

Figure 72. Graph. Load-strain behavior of the epoxy key............................................................ 88

Figure 73. Photos. The two failed surfaces................................................................................... 88

Figure 74. Diagram. Sketch of the crack line. .............................................................................. 88

Figure 75. Photos and sketch. Railing post specimen................................................................... 90

Figure 76. Photo and diagrams. Railing post test setup................................................................ 91

Figure 77. Photo and diagram. Detailing of steel beam-structural frame connection. ................. 92

Figure 78. Photos and diagrams. Location of transducers used during the test............................ 93

Figure 79. Graph. Load-displacement behavior of railing post end (string pot 2). ...................... 95

Figure 80. Photos. Failure mode of the railing post-FRP deck panel connection. ....................... 96

Figure 81. Graph and photo. Vertical displacement of the railing post, Test 1............................ 97

Figure 82. Diagram. Railing post connection (deformed shape, not to scale).............................. 97

Figure 83. Photos. HDPE deformation at different loading levels, Test 2. .................................. 99

Figure 84. Graph. Horizontal deflection (x-direction), Test 2.................................................... 100

Figure 85. Graph. Vertical displacement (y-direction), Test 2................................................... 100

Figure 86. Graph. String pot 4 movement, Test 2. ..................................................................... 101

Figure 87. Photos and graphs. Movement of three bolts on FRP back panel using digital image 

correlation, Test 1. ................................................................................................................ 102

Figure 88. Diagram and photos. Expansion bolt connection...................................................... 103

Figure 89. Photos. FRP specimen used for pull-off tests............................................................ 106

Figure 90. Photos. Dollies mounted to two test areas................................................................. 107
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Figure 91. Photos. Failure surfaces of aggregate to adhesive pull-off tests (dollies 4, 5, and 6).

............................................................................................................................................... 108

Figure 92. Photos. Failure surfaces of adhesive to FRP pull-off tests (dollies 7, 8, and 9)........ 108

Figure 93. Photo. Test panel mounted on top of fire chamber. .................................................. 110

Figure 94. Photo. Support beams spaced at 2 feet. ..................................................................... 110

Figure 95. Photo. 1,600-lb water tank used as concentrated load............................................... 111

Figure 96. Photos. Placement of thermocouples on the test panel.............................................. 111

Figure 97. Photo. The test panel just after the test stopped. Note that the top surface kept cooler 

and ended up with little deterioration. .................................................................................. 115

Figure 98. Photo. Specimen immediately after the test. Note the extent of damage on the bottom.

............................................................................................................................................... 115

Figure 99. Photo. Close-up of the open end of the panel after the test....................................... 115

Figure 100. Photo. The glass fiber on the bottom has frayed due to burn-off of the resin matrix.

............................................................................................................................................... 116
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LIST OF TABLES

Table 1. Tube testing....................................................................................................................... 4

Table 2. Test methods used in characterization............................................................................ 14

Table 3. Comparison of fiber architectures................................................................................... 16

Table 4. Comparison of laminate properties................................................................................. 17

Table 5. Suggested design values. ................................................................................................ 23

Table 6. Material properties for the definition of a unidirectional lamina.................................... 25

Table 7. Test methods used in characterization............................................................................ 26

Table 8. Test laminates for characterization of lamina properties................................................ 27

Table 9. Summary of physical test data for laminate samples...................................................... 27

Table 10. Suggested lamina design values for ply based design and analysis. ............................ 30

Table 11. Predicted properties of pultruded tube.......................................................................... 33

Table 12. Ply details for horizontal walls of pultruded tube......................................................... 34

Table 13. Ply details for vertical walls of pultruded tube............................................................. 35

Table 14. Areal reinforcement weights (oz/yd2) of potential tube laminates. .............................. 35

Table 15. Test methods used in characterization.......................................................................... 37

Table 16. Summary of physical test data for tube laminate samples............................................ 38

Table 17. Summary of physical test data from outer wrap laminate samples. ............................. 39

Table 18. Published grout properties. ........................................................................................... 44

Table 19. Results of grout testing. ................................................................................................ 45

Table 20. Relative merits of grouts for the application (i.e., fill material). .................................. 46

Table 21. Dimensions and thicknesses of FRP tubes (no grout). ................................................. 48

Table 22. Details of FRP grouted tubes........................................................................................ 49

Table 23. Test program—FRP tubes no grout.............................................................................. 51

Table 24. Test program—grouted FRP tubes. .............................................................................. 54

Table 25. Details of panels............................................................................................................ 61

Table 26. Test program—FRP panel without grout...................................................................... 63

Table 27. Test program—grouted FRP panels. ............................................................................ 67

Table 28. Flexure stiffness as function of increasing number of fatigue cycles........................... 78

Table 29. Load-displacement data for string pot 2. ...................................................................... 94

Table 30. Test 2 HDPE pad deformation...................................................................................... 98

Table 31. Pull-off test results...................................................................................................... 107
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Table 32. Details of thermocouple placement. ........................................................................... 112

Table 33. Deflection measurements............................................................................................ 113
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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
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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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1

1. INTRODUCTION

This report summarizes project Phase I (Tasks 2 through 13). The broad objective of Phase I was 

to identify the most suitable materials, subcomponents, assembly methods, installation details, 

and wearing surface for the manufacture and deployment of a bridge deck designed to 

incorporate glass fiber-reinforced polymer (FRP) composite materials. Tasks 2 through 6 

involved preliminary design, and Tasks 7 through 13 involved testing. The preliminary design 

tasks are documented in a previously published report, FHWA-HIF-12-021.

The primary focus of this project has been on moveable bridges for two reasons: the lightweight 

nature of the deck and the fact that it provides a solid surface that protects the structure. These 

are especially beneficial for moveable bridges. However, over the course of the project, the 

Federal Highway Administration (FHWA) modified the title of the project to be simply 

“Composite Bridge Decking,” since the deck’s advantages are not restricted to use on just one 

class of bridges. The deck system can be also used on conventional fixed bridges, with similar 

benefits. Constructability was shown on a 40-foot-long, fixed bridge in Allegany County, NY, as 

part of a proof-of-concept installation. Deck-work started on August 28, 2012, was completed 

successfully, and the bridge was opened to traffic on September 27, 2012. 
2
3

2. TESTING

TESTING PROGRAM

The testing program consisted of an evaluation of the following: 

• Materials.

• Tube subcomponents.

• Assemblies.

• Structural panels.

• Details.

Upon conclusion, the researchers provided a summary of the testing program to the project 

Technical Advisory Panel, and the Panel provided comments. See section 3.

MATERIALS

Publication FHWA-HIF-12-020, Laminate Specification and Characterization, describes the FRP 

materials considered and tested for this project. Appendices A through C provide addenda to the 

Laminate Specification and Characterization report. Appendix D summarizes the testing and 

selection of grout material. 

TUBE SUBCOMPONENTS

Table 1 details the testing of the tube specimens, and Appendix E presents findings of these tests.
4

Table 1. Tube testing.

Test 

Type

No. of

Specimens 

(10-ft span)

Description Purpose

1 1 Empty tube with strain gages to obtain 

load-deflection data.

Calibrate finite element 

analysis. 

2 1 Tube filled (wide cell) with the #1 choice 

of grout, tested with strain gages to obtain 

load-deflection data. Tested wide side up.

Calibrate finite element 

analysis and assess 

performance of the bond 

interface. Compare 

performance of grouts.

3 1 Tube filled (narrow cell) with the #1 choice 

of grout, tested with strain gages to obtain 

load-deflection data. Tested wide side 

down. 

Same as above but with 

narrow cell filled.

4 1 Tube filled (wide cell) with the #2 choice 

of grout, tested with strain gages to obtain 

load-deflection data. Tested wide side up. 

Calibrate finite element 

analysis and assess 

performance of the bond 

interface. Compare 

performance of grouts.

5 1 Tube filled (narrow cell) with the #2 choice 

of grout, tested with strain gages to obtain 

load-deflection data. Tested wide side 

down. 

Same as above but with 

narrow cell filled.

6 3 Simple deflection test of a tube filled (wide 

cell) with the #1 choice of grout, tested 

wide side up, then wide side down.

Check consistency of 

interface performance and 

relative performance of tube 

up vs. down.

7 3 Simple deflection test of a tube filled 

(narrow cell) with the #1 choice of grout, 

tested wide side up, then wide side down.

Check consistency of 

interface performance and 

relative performance of tube 

up vs. down.

8 3 Simple deflection test of a tube filled (wide 

cell) with the #2 choice of grout, tested 

wide side up, then wide side down.

Check consistency of 

interface performance and 

relative performance of tube 

up vs. down.

9 3 Simple deflection test of a tube filled 

(narrow cell) with the #2 choice of grout, 

tested wide side up, then wide side down.

Check consistency of 

interface performance and 

relative performance of tube 

up vs. down.

STRUCTURAL PANELS

Twelve full-depth panels measuring 3 feet by 11 feet were tested to determine response under 

flexure, shear, and ultimate failure. The following describes the three panel types that were 

tested:
5

• Baseline: One panel type was tested without any grout to give a true indication of how 

much benefit is derived from the grout fill. Additionally, discussions with bridge owners 

revealed that they do not always need the added grout because they prefer a lighter deck.

For instance, if the steel stringer spacing is only 2 feet, an unfilled panel is adequate; tight 

stringer spacing like this is often the case if the bridge was originally designed for 2-inchthick timber deck. Also, there may be times when a historic bridge will always be posted 

for weight restriction because of the condition of the primary members. In this case a 

deck capable of carrying extremely heavy trucks is unwarranted. Testing determined that,

in these situations, a deck can function perfectly without the addition of grout. Four 

panels of this type were tested in flexure.

• Top filled: Panels were tested that had grout in the top of all the tubes, similar to the 

original prototype. Half of the tubes had the wide cell filled and the others had the narrow 

cell filled. This was expected to give good plate action to the surface of the deck, helping 

to distribute the wheel loads. Most decks are designed as simply supported spans between 

stringers, so putting grout in the top portion of each tube is consistent with this approach.

Two panels were made with each grout (epoxy and cementitious), resulting in a total of 

four panels of this type being tested in flexure.

• Alternating Grout: Conversations with the Florida DOT have highlighted the fact that 

decks on moveable bridges sometimes have compressive stresses in the top surface, and 

at other times the top surface is in tension. For example, when the span is being lifted, the 

stresses typically reverse. For these situations, it may be desirable to have grout in both 

the top and bottom of the panels so that compressive loads can be carried efficiently for 

either positive or negative bending. Tests were done with grout only in the wide cell, 

alternating between the top and bottom. Two panels were made with each grout (epoxy 

and cementitious), resulting in a total of four panels of this type being tested in flexure.

Documentation of the testing is presented in the following appendixes:

• Appendix F summarizes flexure testing of the structural panels as well as ultimate failure. 

• Appendix G explains the short panel shear test with a concentrated load.

• Appendix H summarizes a panel fatigue test.

ASSEMBLY

Figures 1 through 7 illustrate the assembly of deck panels from tube subcomponents.
6

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.

4.5”
7

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.
8

Figure 7. Photo. Adhesive and stone are applied for course 1 of the wearing surface. (The black 

rectangle is a bearing pad for the bridge railing post.)

DETAILS

Special testing categorized as “details” includes:

• Panel-to-panel field joint.

• Bridge railing anchorage.

• Connection to steel.

• Wearing surface.

• Fire testing.

Documentation of these tests is provided as follows:

• Appendix I describes the results of testing on the grouted panel-to-panel field joint.

• Appendix J describes the results of testing the bridge rail post anchorage and connections 

to supporting steel.

• Appendix K gives results of wearing surface pull-off tests. 

• Appendix L provides the laboratory report for fire testing.
9

3. AFTER-TEST REVIEW

On August 14, 2012, the research team provided the project Technical Advisory Panel with an 

update and summary of the testing that had been done. The presentation used for this is included 

in Appendix M.

The Technical Advisory Panel’s comments are listed below, followed by the project team’s 

responses:

• Question: How is the wearing surface repaired/refreshed?

o Response: Since the second course of the wearing surface is only 1⁄4 inch thick, a 

new 1⁄4-inch surface can be applied if the additional 3 psf weight is not critical.

Otherwise, the polymer concrete wearing surface can be milled off and resurfaced 

with a fresh course of the same material.

• Question: Will this be available in various panel sections/sizes? Will there be a table for 

design engineers to use as a design guide?

o Response: The deck design is valid for a range of spans, and this can be tabulated 

to give designers the ability to pick the suitable deck type for their stringer 

spacing. Spans between 2 and 10 feet were tested. Sections were tested with 

various stiffening materials: empty, epoxy grout in the top only, and epoxy grout 

alternating between top and bottom.

• Question: What about dynamic loading?

o Response: An impact factor was applied to the American Association of State 

Highway and Transportation Officials (AASHTO) design load. The field testing 

that is planned may provide additional information about the actual dynamic 

loading induced by truck loads.

• Question: Previous FRP decks have had trouble with the deck-deck joints, deck-steel 

connections, and the wearing surface. What has been done to prevent those problems?

o Response: “Details” have been given a lot of attention in the design/analysis, 

material testing, and proof testing stages of the project. The modeling and 

subsequent testing assures us that the proposed details will function well in 

service.

• Comment: In the preliminary design stage, a reviewer’s only concern had been about the 

type of grout used. He was pleased to see that we addressed that issue by selecting a lowmodulus grout that will be compatible with the fairly flexible deck panels.
10
11

4. CONCLUSIONS

The testing performed in Phase I helped determine the best selection of material, subcomponents, 

assembly method, and details. Through these tests, cementitious grout was found to be 

insufficient because of its low bond strength with the pultruded tube. Epoxy grout is preferred. In 

some applications, the panel will perform adequately without any grout because of its innate 

robustness and stiffness.

The bridge railing test demonstrated that the anchorage connection meets the Test Level-2 

loading requirements found in AASHTO’s Load and Resistance Factor Design (LRFD) Bridge 

Specification. When load on the bridge rail post was increased to failure, it resulted in a type of 

damage that will be easily repairable using epoxy grout. Further testing may show that higher 

test levels can be achieved by filling this area of the FRP deck with epoxy grout to resist a 

punching failure.

The deck panels are suitable for the intended application under standard AASHTO loading.
12
13

APPENDIX A: DETERMINATION OF PRELIMINARY DESIGN PROPERTIES

OVERVIEW

The trapezoidal profile used to create the replacement deck slabs in this project was developed 

from an earlier design developed at the University of Buffalo. In July 2010, XC Associates 

fabricated a protective ice shield for a bridge in Erie County, NY, using this profile design. The 

trapezoidal shape was slightly different than that proposed for the current project in that it only 

used a single grout cavity rather than two (see figure 8). The structure was fabricated from two 

trapezoids each approximately 0.1 inch thick. The smaller trapezoid was designed to be 

adhesively bonded inside the larger trapezoid. A series of these tubes were then adhesively 

bonded together to form a wall unit. To ensure the structural integrity of the wall unit, the 

assembly was completely wrapped by an outer laminate.

Figure 8. Diagram. Geometry of ice shield profile with single cavity.

The current bridge deck required significantly higher load bearing capacity than the ice wall 

units. To establish a feasible design, engineers planned to work from earlier finite element 

analysis models to determine suitable dimensions and FRP laminate configurations for the 

current deck application. To do this it was necessary to develop preliminary design properties 

which could be used in the finite element analysis modeling. Once the design had been 

developed, samples of the final laminates could then be produced and tested to validate predicted 

behavior.

This appendix outlines work done to develop design properties from the laminate configuration 

utilized in the earlier ice wall project. It also includes comparative testing performed on two

alternative laminates of similar configuration produced by a different manufacturer.

TEST METHODS UTILIZED IN CHARACTERIZATION WORK

The test methods used in this characterization are outlined in table 2. These tests yield strength 

and modulus values in both primary directions (denoted as 0° for the primary fiber axis and 90°

for the direction normal to that axis). Properties are determined in both tension and compression. 
14

In-plane shear strength was also determined. The fiber content of each panel was also determined 

to allow proper comparison of the resulting properties from each laminate.

Table 2. Test methods used in characterization.

ASTM Test No. Title Properties Obtained Symbol

D3039/3039M-08 Standard Test Method for Tensile

Properties of Polymer Matrix 

Composites

Ultimate tensile strength 

(0o) σ11T

Ultimate tensile strain (0o) ε11T

Modulus of elasticity 

(chord) (0o) E11T

Ultimate tensile strength 

(90o) σ22T

Ultimate tensile strain (90o) ε22T

Modulus of elasticity 

(chord) (90o) E22T

D6641/D6641M-09 Standard Test Method for Compressive

Properties of Polymer Matrix 

Composite Materials Using a 

Combined Loading Compression 

(CLC) Test Fixture

Ultimate compression 

strength (0o) σ11C

Ultimate compression 

strain (0o) ε11C

Modulus of elasticity 

(chord) (0o) E11C

Ultimate compression 

strength (90o) σ22C

Ultimate compression 

strain (90o) ε22C

Modulus of elasticity 

(chord) (90o) E22C

D7264/D7264M-07 Standard Test Method for Flexural

Properties of Polymer Matrix 

Composite Materials

Ultimate flexural strength 

(0o) σ11F

Ultimate flexural strain (0o) ε11F

Flexure Modulus (chord) 

(0o) E11F

Ultimate flexural strength 

(90o) σ22F

Ultimate flexural strain 

(90o) ε22F

Flexure Modulus (chord) 

(90o) E22F

D3171-09 Standard Test Method for Constituent

Content of Composite Materials 

Test Method I, Procedure G: Matrix 

Burnoff in a Muffle Furnace

Fiber fraction - mass mf

Fiber fraction - volume vf

D2344/D2344M-00 Standard Test Method for Short-Beam 

Shear Strength of Polymer Matrix 

Composite Materials and Their 

Laminates

Short Beam Shear Strength

LAMINATES EVALUATED

The laminate produced by XC Associates was produced using Vectorply E-glass fabrics and 

Derakane 8084 vinyl ester resin. The fabric layup sequence was [E-QX2600 / E-LT5500 / E-
15

QX2600] with E-QX2600 being a 25.18 oz/yd2 Quadraxial E-glass fabric and E-LT5500 being a 

54.33 oz/yd2 Biaxial E-glass fabric. The resulting ply sequence was:

0o 6.40 oz/yd2

+45o 6.27 oz/yd2

90o 6.24 oz/yd2

-45o 6.27 oz/yd2

0o 50.97 

oz/yd2

90o 3.36 oz/yd2

0o 6.40 oz/yd2

+45o 6.27 oz/yd2

90o 6.24 oz/yd2

-45o 6.27 oz/yd2

The Compmillenia panels were also produced using Vectorply E-glass fabrics, though different 

fabrics were selected due to materials held in-stock at Compmillenia. The fabric layup sequence 

in these panels was [E-LT3200 / E-LM1810 / E-BX2400 / E-LM1810 / E-LT3200], with ELT3200 being a 31.36 oz/yd2 biaxial fabric, E-LM1810 being a 27.06 oz/yd2 

uniaxial fabric with 

mat backing and E-BX2400 being a 23.90 oz/yd2 double bias fabric with fibers oriented at +45°/-

45°. The resulting ply sequence from this configuration was:

90o 13.44 

oz/yd2

0o 17.92 

oz/yd2

0o 17.92 

oz/yd2

CSM 9.00 

oz/yd2

+45o 11.95 

oz/yd2

-45o 11.95 

oz/yd2

0o 17.92 

oz/yd2

CSM 9.00 

oz/yd2

0o 17.92 

oz/yd2

90o 13.44 

oz/yd2

Compmillenia provided two sample laminates with the alternative layup. One was produced 

using a standard vinylester (CoRezyn VE8121) and the other with an alternative fire retardant 

vinylester resin (CoRezyn VE8441). While the ply sequence of these panels are different from 
16

each other, the total weight of directional reinforcement in each panel is relatively close, as 

shown below in table 3. 

Table 3. Comparison of fiber architectures.

Direction Ice Shield 

(oz/yd2)

Compmillenia

(oz/yd2)

0o 63.8 71.7

90o 15.8 26.9

+/- 45o 25.1 23.9

CSM 0 18.0

Theoretical Thickness 0.106 in. 0.15 in.
17

TEST RESULTS

Table 4 summarizes the results obtained through physical testing.

Table 4. Comparison of laminate properties.

OBSERVATIONS ON PHYSICAL TESTING

From the test data it was observed that the two Compmillenia panels were very similar in terms 

of mechanical properties. There was only a minimal difference in the fiber volume fraction 

achieved in each panel; thus, the mechanical performance is very similar. The variation in 

ultimate strength values reflects the slight difference seen in corresponding strain values. The 

laminates display a highly linear elastic behavior up to failure, and the strength differences 

simply relate to the different amount of physical elongation seen prior to failure. Given the level 

of within-sample scatter seen in each sample sets it would seem reasonable to conclude that the 

different resin used in these panels makes a minimal difference to the mechanical performance.

Modulus

Tension ET0 4.36 MSI 0.15 MSI 2.48 MSI 0.20 MSI 2.56 MSI 0.18 MSI

ET90 2.02 MSI 0.25 MSI 1.86 MSI 0.26 MSI 1.99 MSI 0.44 MSI

Compression EC0 2.89 MSI 0.42 MSI 2.36 MSI 0.35 MSI 2.37 MSI 0.24 MSI

EC90 2.18 MSI 0.48 MSI 1.84 MSI 0.13 MSI 1.93 MSI 0.13 MSI

Flexure EF0 1.83 MSI 0.09 MSI 2.05 MSI 0.08 MSI 1.91 MSI 0.07 MSI

EF90 1.77 MSI 0.08 MSI 2.38 MSI 0.07 MSI 2.51 MSI 0.07 MSI

Ultimate Strength

Tension σT0 84.51 KSI 1.70 KSI 49.80 KSI 2.05 KSI 47.31 KSI 3.42 KSI

σT90 28.57 KSI 2.05 KSI 29.75 KSI 1.81 KSI 28.40 KSI 0.44 KSI

Compression σC0 60.08 KSI 3.35 KSI 54.41 KSI 4.03 KSI 45.58 KSI 5.07 KSI

σC90 30.09 KSI 1.34 KSI 32.32 KSI 2.07 KSI 27.22 KSI 2.20 KSI

Flexure σF0 37.78 KSI 1.81 KSI 66.08 KSI 4.06 KSI 56.63 KSI 3.60 KSI

σF90 47.40 KSI 1.72 KSI 64.56 KSI 4.30 KSI 61.54 KSI 3.40 KSI

Strain at Max. Stress

Tension εT0 2.30 % 0.13 % 2.44 % 0.14 % 2.37 % 0.20 %

εT90 2.40 % 0.12 % 2.13 % 0.11 % 2.23 % 0.21 %

Compression εC0 2.62 % 0.38 % 2.43 % 0.54 % 2.14 % 0.27 %

εC90 2.38 % 0.95 % 2.07 % 0.40 % 1.44 % 0.13 %

Flexure εF0 3.52 % 0.25 % 4.23 % 0.11 % 3.84 % 0.22 %

εF90 3.58 % 0.22 % 3.06 % 0.14 % 2.77 % 0.16 %

In Plane Shear Strength τ12 13.30 KSI 0.41 KSI 14.02 KSI 0.59 KSI 13.98 KSI 0.60 KSI

τ21 15.41 KSI 1.51 KSI 13.59 KSI 0.46 KSI 13.69 KSI 0.82 KSI

Short Beam Strength 5.81 KSI 0.28 KSI 4.98 KSI 0.26 KSI 5.16 KSI 0.26 KSI

Fiber Content (%) mass mf 70 % 54 % 52 %

volume vf 48 % 31 % 30 %

Thickness t 0.113 in 0.0012 in 0.218 in 0.004 in 0.222 in 0.003 in

Property Symbol XCA Ice Wall Compmillenia VE-8121 Compmillenia VE-8441

Mean Std. Dev. Mean Std. Dev. Mean Std. Dev.
18

BEHAVIOR IN THE PRINCIPAL FIBER DIRECTION (0o)

Under tension, the XC Associates panel displays considerably higher properties in the dominant 

fiber direction (0°). This is indicative of the fact that this panel possesses a significantly higher 

proportion of its total panel thickness with fibers in that direction. As can be seen from figure 9, 

in the Compmillenia panel approximately 16 percent of the total thickness of the laminate is 

occupied by fiber that runs in the 0° direction, compared with 29 percent in the XC Associates

ice wall laminate (184 percent difference). It would thus be reasonable to expect that the 0°

properties of the XC Associates ice wall panel would be a little under double those of the 

Compmillenia panels. This is seen in the test data. ET0 for the ice wall is 170-175 percent of the 

Compmillenia panels, and σT0 for the ice wall is 170 percent of the Compmillenia panel. 

Statistical analysis indicates that data from the two Compmillenia panels are from a common 

statistical population, which would be expected based on the identical architecture. 

Figure 9. Graph. Constituent content of test laminates as a percentage of total laminate thickness.

From the strain data it can be observed that all of the specimens fail at approximately the same 

strain. Previous in-house testing has indicated tension capacity in the fiber direction is dominated 

by the fiber and that the average failure strain of unidirectional glass fiber laminates is around 
19

2.4 percent (standard deviation of 0.56 percent) irrespective of the amount of reinforcement or 

the resin type. Observation of the average strain limits of the three laminates tested here indicates 

they all fail close to this level. Statistical analysis of the data indicates that the three strain data 

sets are part of the same statistical population. It is therefore reasonable to conclude that it is the 

fiber oriented along the load direction which is controlling the failure of these laminates under 

tension. When the fibers in the load direction reach their strain limit, rupture occurs and results in 

catastrophic failure of the laminate. 

For compression properties in the principal fiber direction, it can be seen that the resin begins to 

play a more significant role in the mechanical properties obtained. In terms of ultimate capacity, 

the strain at break results of the three samples are found to be from the same statistical 

population, with a population mean of 2.41 percent. This again indicates that the fiber oriented in 

the load direction is primarily responsible for determining the laminate failure. 

However, unlike the behavior under tension, when the laminates are tested in compression 

parallel to the principal fiber direction, there is not a direct correlation between the fiber content 

and the resulting modulus (EC0). In this instance, the difference between the ice wall laminate 

modulus and the modulus for the Compmillenia panels is only around 22 percent, not the 

expected 70 to 80 percent. This would indicate that the other laminate constituents play a more 

significant role under compression. Similar results are seen with the strength data (σC0), where 

the ice wall panel only displays 10 percent (VE-8121) and 32 percent (VE-8441) strength 

improvements over the Compmillenia panels. 

BEHAVIOR IN THE OFF-AXIS FIBER DIRECTION (90o)

In the 90° direction it can be seen that the proportion of the laminate thickness aligned with the 

load (90° fibers aligned with 90° axial load) is relatively close for all the panels (7.24 percent vs.

5.94 percent and 5.74 percent). It would therefore be anticipated that for fiber dominated 

properties the observed values in the 90° direction would be relatively close to each other. This is 

consistent with the observed data. 

When normalized against the amount of fiber in the 90o direction as a proportion of laminate 

thickness, both the tension and compression modulus (E90T, E90C) are statistically from the same 

populations, indicating the dominant role of the fiber in the compression response of the 

laminates. 

In terms of strength and strain data on ultimate capacity, the values obtained in testing are 

relatively close. However, deeper analysis of the data indicates statistically significant variations 

which cannot be fully explained by the proportion of load bearing fiber. Strain data in tension 

indicate that the Compmillenia panels are statistically from the same population, but there is 

significant variation between these values and those of the ice wall panel (average 2.14 percent

vs. 2.44 percent). The reason for this variation is unknown and would require further testing to 

verify. It is thought that some of the variation may be due to the overall architecture of the 

laminates. With the Compmillenia panels all of the 90o fiber is located on one side of the 

laminate, while in the ice wall panel the 90o fiber is more evenly distributed throughout the 

thickness of the panel. It may be that having adjacent plies in other directions helps to preserve 
20

the integrity of the fibers to higher strain levels by better distributing load through the laminate 

thickness.

Under compression loads the data display significantly greater variation in terms of ultimate 

capacity. Statistical analysis of the compression strain data indicates statistically significant 

differences between all three sets of data. The average compression failure strains for the ice 

wall, VE-8121, and VE-8441 panels are 2.38 percent. 2.07 percent, and 1.44 percent,

respectively. Statistically, the ice wall and VE-8121 data are from the same population, but the 

data for the VE-8441 panel are significantly lower. An examination of the failed specimens does 

not provide any obvious reason for the discrepancy in failure strains. Failure in inherently 

compression is more variable than corresponding tensile failure due to the increased number of 

possible failure mechanisms. Buckling can occur on both a macroscopic specimen level and a 

microscopic fiber level, with the latter being particularly difficult to identify. Examination of the 

stress-strain curves for the VE-8441 sample does not indicate any obvious buckling in the 

specimens. Additionally, all of the failures were properly within the gage length, so there was no 

obvious premature failure due to the grips. At this point it is possible to identify the difference 

between the samples, but it is not possible to further explain these variations.

SHEAR BEHAVIOR

In addition to axial tension and compression, shear strength was evaluated both in-plane and 

through the thickness between the individual laminate plies. In-plane shear testing was 

conducted using a V-notch shear test. Two different orientations were tested, as shown in figure 

10.

Figure 10. Diagram. Fiber directions for in-plane shear strength testing.

The V-notch shear test induces principal tension and compression stresses at +45o and-45o. On 

the basis of the previous discussions it would therefore seem reasonable to expect the in-plane 

strength of the laminates to be significantly influenced by the fiber oriented at +/- 45o.

Statistical analysis of the data from the two Compmillenia panels indicate they are from a single 

population, indicating that the behavior is fiber dominated. There is also no statistically 

significant difference between the τ12 data and the τ21 data. If the resin or the fiber oriented off 

the +/-45o axis were playing a significant role in determining the in-plane shear strength, it would 

expected that statistically significant differences would be evident in the four data sets. The 

0o

90o

90o

0o

1-2 In-Plane Shear Strength – τ12 2-1 In-Plane Shear Strength – τ21
21

absence of such differences would indicate that the fiber in the +/-45o directions does control the 

shear capacity.

As would be expected from the significant difference between their +/-45o fiber percentages, 

there is a statistically significant difference between the shear strengths of the ice wall and 

Compmillenia panels. However, while the ice wall panel displays an increase in in-plane shear 

capacity, there is not a direct correlation with the amount of +/-45o fiber present. The ice wall

panel has an average shear strength of 12.4 ksi while the Compmillenia panels have an average 

of 11.3 ksi. This is a strength increase of only around 10 percent for the ice wall panel despite it 

having 12 percent of its thickness as +/-45o versus only 5 percent for the Compmillenia panels. 

All three panels have a similar load versus deflection behavior trend.

Interlaminar shear capacity was evaluated using a short beam shear test. This test uses a 

relatively short span under flexural loading to induce shear failure of the specimen between the 

individual plies, typically at the neutral axis. The interlaminar strength is generally considered to 

be a resin dominated property; however, the orientation of plies on either side of the failure plane 

will also play a role in the capacity obtained. The Compmillenia panels display relatively 

uniform results and were found to be statistically from the same population. Given the identical 

fiber architecture and similarities in the resin properties, this result would be consistent with 

expectations. The results for the ice wall panel are higher than the ones for the Compmillenia

panels. It is thought that this is attributable to the differences in fiber architecture and resin 

properties, although no direct correlation can be established at this time. 

COMPARISON OF PANEL RESULTS

Some of the discrepancies between the ice wall panel and the two Compmillenia panels are due 

to the slightly different fiber architecture used by the two manufacturers. In a commercial 

context where manufacturers were relying on existing reinforcement stocks to produce the 

panels, the selection of the different reinforcements was entirely reasonable. Most manufacturers 

seem to work with a selection of preferred reinforcement products and then adapt designs around 

those products. The challenge for design engineers is how to accommodate those differences and 

to provide a valid comparison between two different options. 

As can be seen from the test data, many of the properties in question tend to be fiber dominated 

due to the reinforcement architecture selected. Once properties are correlated against the actual 

amount of reinforcement used, what initially appear to be differences in panel quality can be 

identified as the simple result of varied reinforcement quantities. This is similar to reinforced 

concrete. Two finished beams may look similar from the outside and may have both been 

manufactured to high quality. However, if their internal reinforcement is different, one will 

provide significantly higher capacity than the other. The result is not the result of a quality flaw 

but rather stems from what would be an intentional design decision. The same is true for 

composites.

Beyond fiber architecture, the other principle reason for the difference in panel performance is 

the resin content of the panels. This is purely the result of manufacturing methodology. The ice 

wall panel was produced using a VARTM (vacuum infusion) process which infuses the resin into 
22

the fiber under vacuum, while the Compmillenia panels were produced by wet layup followed by 

a vacuum consolidation. The resin content differences that result from these processes are 

inherent to the processes themselves. 

Both processes place the laminate under a plastic film to create an envelope which is then 

evacuated to create a pressure differential between the inside of the envelope and ambient 

atmospheric conditions. This pressure differential is used to consolidate the laminate with the 

aim of achieving a higher proportion of fiber in the final product. However the mechanism for 

achieving that consolidation is different with each method. VARTM first consolidates the dry 

reinforcement and then allows a limited amount of resin into the pre-consolidated fiber. For a 

vacuum bagged wet layup the reinforcement is initially wet out with resin under ambient 

conditions. Once the reinforcement and resin have been successfully combined (typically with a 

resin excess), the wet laminate is placed under the vacuum film and the pressure differential is 

induced to essentially squeeze out excess resin. While both processes use the same consolidation 

pressure, the VARTM process typically produces higher fiber percentages. This is because it is 

far easier to compact the dry fiber layers in VARTM than it is to displace a relatively viscous 

liquid from within the fibers to compact the wet layup. The result would be that, for a given fiber 

architecture and resin, a VARTM produced product would be slightly thinner than a vacuum 

bagged wet layup one. However, it is important to remember that the actual amount of 

reinforcement would not change—all that would happen is that one panel would possess less 

resin than the other. 

For properties which are fiber dominated, the actual structural capacity of the two laminates 

would not be changed because the amount of reinforcement would be the same. However, the 

resulting properties, which are generally characterized in terms of force per unit area, would 

appear higher for the VARTM laminate due to the reduced thickness. It is essential to remember 

that thickness is essentially a manufacturing variable, not an inherent characteristic of the 

material.

Therefore, when comparing the ice wall panel and the two Compmillenia panels, it is necessary 

to separate manufacturing effects from the potential viability of the laminates. In producing the 

sample panel, Compmillenia indicated that a VARTM process could be used in the production of 

bridge components but that their standard production method was vacuum bagged wet layup. 

From the data obtained it would be reasonable to anticipate that if Compmillenia switched to a 

VARTM process the resulting laminate properties would be correspondingly higher.

CONCLUSION

From the test results it can be concluded that all three test panels provide mechanical 

performance consistent with the fiber architecture and the manufacturing method used. Both 

manufacturers produced panels that exhibited sufficient quality to be utilized in an actual bridge 

deck fabrication.

Assuming that a laminate specification is developed that reflects the original ice wall laminate 

construction and that it specifies the use of a VARTM process, the properties in table 5 could be 

specified for design calculations. 
23

Table 5. Suggested design values.

Given the statistical nature of material failure, it is customary to use statistically based capacity 

values for engineering design. In this instance, B-basis values are given for the ultimate strength 

and strain capacity properties. The B-basis value is a 95 percent lower confidence bound on the 

tenth percentile of a specified population of measurements. Composite Materials Handbook 17 

(formerly MIL-HDBK-17) adopts A-basis and B-basis values for characteristic properties of 

composite materials in engineering design. For the current project, A-basis values (95 percent

confidence on the first percentile) are seen as overly conservative, particularly given that 

validation testing will be conducted at all stages of the design and development process. B-basis 

values are therefore recommended for capacity characterization.

Symbol

Modulus

Tension ET0 4366 KSI

ET90 1988 KSI

Compression EC0 2889 KSI

EC90 2180 KSI

Ultimate Strength

Tension σT0 84.56 KSI 78.90 KSI

σT90 29.15 KSI 26.25 KSI

Compression σC0 60.05 KSI 50.04 KSI

σC90 30.17 KSI 25.82 KSI

Strain at Max. Stress

Tension εT0 2.30 % 1.97 %

εT90 2.44 % 2.32 %

Compression εC0 2.62 % 1.46 %

εC90 2.05 % 0.77 %

In Plane Shear Strength τ 12.34 KSI 10.15 KSI

Short Beam Strength 5.80 KSI 5.16 KSI

Fiber Content (%) mass mf 70 %

volume vf 48 %

Thickness t 0.113 in

Property Mean B-Basis Value
24

APPENDIX B: DETERMINATION OF LAMINA DESIGN PROPERTIES

OVERVIEW

The detailed analysis of FRP structures and sub-components is a typically a complex undertaking 

requiring the use of advance finite element analysis techniques. Due to their inherent brittleness 

and the directional nature of composite laminates, simplified analysis methods developed for 

isotropic materials such as steel often do not provide sufficient detail to ensure adequate 

structural performance with FRP composites. To utilize these methods it is necessary to develop 

good representative material properties which may be input into finite element models.

Physically, FRP laminates are constructed from a series of ply layers which after curing perform 

as a single unified layer. In instances where the laminate ply sequence is predetermined, it is 

possible to construct and test a laminate of the specified construction and to then input those 

properties into a finite element model. However, in most instances the designer does not know 

the ply sequence beforehand and will use an iterative process which moves between various ply 

sequences and structural forms to find an optimal combination of both. 

Thankfully, modern finite element analysis packages typically possess laminated plate elements 

which allow the designer/analyst to specify various reinforcements and orientations. The 

individual layer properties can be entered and are ultimately combined in the model using 

classical laminate theory. The basic building block of this approach is the individual 

unidirectional ply or lamina. Thus, properly defining the properties of a unidirectional lamina is 

the key to developing viable structural models.

FRP materials are orthotropic in nature, which means the characterization of their mechanical 

behavior is more complex than for isotropic materials such as steel. The full set of material 

properties required to define the unidirectional lamina is given in table 6.

For commercial manufacturing purposes it is often convenient to produce a specified ply 

sequence using a multi-axial fabric. These fabrics combine dry reinforcement for two, three, or 

four laminae in a single fabric where the separate layers are stitched together with a non-loadbearing thread. Analytically, these fabrics are simply multiple unidirectional lamina placed on 

top of each other in different orientations, so it is technically not necessary to separately 

characterize these fabrics if unidirectional lamina properties have already been established. 

However, some designers prefer to characterize these fabrics in addition to the unidirectional 

lamina.

In addition to directional layers, it is relatively common for laminates to include layers of 

randomly oriented short fibers. In dry form these are layers are known as chopped strand mat 

(CSM) and consist of randomly oriented fibers of approximately 2 inches held together in fabric 

form by a compatible binder. These layers are essentially isotropic and must be characterized 

separately from the unidirectional lamina.
25

This appendix outlines the results of testing undertaken to characterize a unidirectional lamina 

and a CSM lamina of E-glass and vinyl ester. Addition testing was undertaken on a biaxial 

lamina (two plies at 0o and 90o) and a double bias lamina (two plies at +45o and -45o). 

Table 6. Material properties for the definition of a unidirectional lamina.

Property Direction Symbol

Modulus of Elasticity 0 E1

90 E2

In-plane Shear Modulus 0-90 G12

90-0 G21

Tensile Strength 0 σ1T

90 σ2T

Compression Strength 0 σ1C

90 σ2C

Ultimate Tensile Strain 0 ε1T

90 ε2T

Ultimate Compression 

Strain

0 ε1C

90 ε2C

In-plane Shear Strength 0-90 τ12

90-0 τ21

In-plane Poisson 

Coefficient

0-90 ν12

90-0 ν21

Lamina Thickness not applicable t

TEST METHODS UTILIZED IN CHARACTERIZATION WORK

The test methods used in this characterization are outlined in table 7. These tests yield strength 

and modulus values in both primary directions (denoted as 0° for the primary fiber axis and 90°

for the direction normal to that axis). Properties are determined in both tension and compression. 

In-plane shear strength was also determined. The fiber content of each panel was also determined 

to allow proper comparison of the resulting properties from each laminate.
26

Table 7. Test methods used in characterization.

ASTM Test No. Title Properties Obtained Symbol

D3039/3039M-08 Standard Test Method for 

Tensile Properties of Polymer 

Matrix Composites

Ultimate tensile 

strength (0o) σ1T

Ultimate tensile strain 

(0o) ε1T

Modulus of elasticity 

(chord) (0o) E1T

Ultimate tensile 

strength (90o) σ2T

Ultimate tensile strain 

(90o) ε2T

Modulus of elasticity 

(chord) (90o) E2T

D6641/D6641M09Standard Test Method for 

Compressive Properties of 

Polymer Matrix Composite 

Materials Using a Combined 

Loading Compression (CLC) 

Test Fixture

Ultimate compression 

strength (0o) σ1C

Ultimate compression 

strain (0o) ε1C

Modulus of elasticity 

(chord) (0o) E1C

Ultimate compression 

strength (90o) σ2C

Ultimate compression 

strain (90o) ε2C

Modulus of elasticity 

(chord) (90o) E2C

D5379/D5379M05Standard Test Method for Shear

Properties of Composite 

Materials by the V-Notched 

Beam Method

In-plane shear strength 

(0-90)

τ12

In-plane shear strength 

(90-0)

τ21

D3171-09 Standard Test Method for 

Constituent Content of 

Composite Materials 

Test Method I, Procedure G: 

Matrix Burnoff in a Muffle 

Furnace

Fiber fraction - mass mf

Fiber fraction - volume vf

D2344/D2344M00Standard Test Method for ShortBeam Shear Strength of Polymer 

Matrix Composite Materials and 

Their Laminates

Short Beam Shear 

Strength

LAMINATES EVALUATED

Four laminates were fabricated for this testing. The test panels are outlined in table 8.
27

Table 8. Test laminates for characterization of lamina properties.

Panel ID Reinforcement

Fabric

Reinforcement 

Description

Ply 

Sequence

LSC-11-LAM010E-LA1312 13.42 oz/yd2 stitched unidirectional [0]4

LSC-11-LAM011E-BX1200 12.54 oz/yd2 stitched +45/-45 double 

bias

[+45/-

45]4

LSC-11-LAM012E-LT1800 17.92 oz/yd2 stitched 0/90 biaxial [0/90]3

LSC-11-LAM013E-M0010 9.0 oz/yd2 stitched CSM [CSM]5

TEST RESULTS

Table 9 summarizes the results obtained through physical testing. 

Table 9. Summary of physical test data for laminate samples.

DISCUSSION OF RESULTS

Unidirectional Lamina Behavior

From the unidirectional lamina results, it can be seen that the properties in the principal fiber 

direction (0o) are significantly higher than the corresponding properties at 90o to the fiber axis. 

Modulus

Tension ET0 2365 KSI 171 KSI 626 KSI 51 KSI 1742 KSI 159 KSI 1094 KSI 99 KSI

ET90 728 KSI 23 KSI 850 KSI 76 KSI 1957 KSI 195 KSI 974 KSI 122 KSI

Compression EC0 2184 KSI 329 KSI 633 KSI 90 KSI 1979 KSI 194 KSI 975 KSI 98 KSI

EC90 824 KSI 125 KSI 1009 KSI 133 KSI 2019 KSI 233 KSI 1131 KSI 130 KSI

Ultimate Strength

Tension σT0 55.85 KSI 3.15 KSI 7.28 KSI 0.27 KSI 32.99 KSI 2.40 KSI 16.60 KSI 1.31 KSI

σT90 3.96 KSI 0.27 KSI 15.65 KSI 0.49 KSI 31.82 KSI 4.04 KSI 15.01 KSI 1.48 KSI

Compression σC0 48.32 KSI 1.71 KSI 10.70 KSI 0.66 KSI 39.68 KSI 3.49 KSI 20.51 KSI 0.61 KSI

σC90 11.45 KSI 1.40 KSI 12.41 KSI 0.32 KSI 37.22 KSI 1.35 KSI 21.97 KSI 1.46 KSI

Strain at Max. Stress

Tension εT0 2.46 % 0.14 % 17.73 % 4.97 % 2.13 % 0.16 % 2.01 % 0.28 %

εT90 0.62 % 0.06 % 10.01 % 1.16 % 2.06 % 0.27 % 1.91 % 0.35 %

Compression εC0 3.56 % 1.13 % 3.84 % 0.92 % 2.69 % 0.42 % 3.01 % 0.65 %

εC90 2.23 % 0.61 % 2.34 % 0.33 % 3.72 % 1.72 % 3.16 % 0.67 %

In Plane Shear Strength τ12 6.39 KSI 0.25 KSI 10.76 KSI 0.30 KSI 6.08 KSI 0.37 KSI 11.34 KSI 0.00 KSI

τ21 4.45 KSI 0.61 KSI 11.21 KSI 0.38 KSI 6.41 KSI 0.26 KSI - KSI 0.75 KSI

Short Beam Strength 40.00 KSI 1.83 KSI 17.80 KSI 0.75 KSI 33.00 KSI 2.51 KSI 21.70 KSI 4.74 KSI

Fiber Content (%) mass mf 40 % 36 % 47 % 35 %

volume vf 21 % 18 % 26 % 18 %

Thickness t 0.126 in 0.148 in 0.116 in 0.135 in

Property

Unidirectional 

Laminate

Double Bias Laminate Biaxial Laminate Random Fiber (CSM) 

Laminate

Mean Std. Dev. Mean Std. Dev. Mean Std. Dev.
28

As the modulus of elasticity is taken early in the stress/strain response, it would be reasonable to 

expect the results for tension and compression modulus to be relatively close to each other. This 

is seen in the test data. Statistical analysis indicates that both the tension and the compression 

data are from the same statistical population. This is found both parallel and perpendicular to the 

fibers. This allows for the determination of a single modulus of elasticity for the material under 

both tension and compression loading. Using the pooled data, the mean modulus of elasticity for 

the laminate parallel to the fibers (E1) is 2.34 MSI (standard deviation 0.329 MSI). The pooled 

modulus of elasticity perpendicular to the fibers (E2) was found to be 0.77 MSI (standard 

deviation 0.097 MSI). It is worth noting that while a single statistical value can be established in 

each direction, there is significantly higher scatter seen in the compression data compared with 

the tension data.

Failure data for tension and compression do not display the same sort of commonality. This is to 

be expected due to the different failure mechanisms which drive behavior under tension and 

compression loading. The data obtained in this testing is seen to be consistent with testing of 

unidirectional laminae previously undertaken by the author. 

Random Fiber Lamina Behavior

As mentioned earlier, the random fiber lamina is expected to be essentially isotropic, and there 

should be no statistically significant difference in the data obtained at 0o and 90o. Analysis of the 

modulus of elasticity results indicates that all four data sets (tension and compression at 0o and 

90o) are statistically from the same population. This yields a mean modulus of elasticity for the 

lamina of 1.07 MSI (standard deviation 0.118 MSI).

In relation to capacity, 0o and 90o tensile strengths are found to be from the same population with 

a mean strength of 15.9 KSI (standard deviation 1.55 KSI). Tensile strain limits are also of the 

same population, giving an overall mean of 1.96 percent (standard deviation 0.303 percent). 

Compression strength and strain are similarly seen to be of the same statistical populations, with 

mean values of 21.18 KSI (std. dev. 1.31 KSI) and 3.08 percent (standard deviation 0.63

percent), respectively.

Based on these findings, shear response was only evaluated in the 0o direction. The mean shear 

strength was found to be 11.34 KSI with a standard deviation of 0.75 KSI.

Biaxial Lamina Behavior 

As mentioned previously, a biaxial fabric is really just two unidirectional layers stitched together 

at 90o to each other. According to manufacturer data from Vectorply, each layer has an equal 

amount of unidirectional reinforcement: 8.96 oz/yd2. It would therefore be expected that the 

lamina properties would be equal at both 0 and 90o.

Analysis of the modulus of elasticity values obtained at both 0o and 90o under tension and 

compression indicated that all the values obtained belong to a common statistical population. It 

was found that the combined data set had a mean modulus of 1.94 MSI (std. dev. 0.219 MSI). 
29

Analysis of the strength data indicates that statistically significant differences exist between the 

tension and compression behavior, but within each load type the results at 0o and 90° are of the 

same population. The mean tension strength (σT) was found to be 32.3 KSI (standard deviation 

3.25 KSI), and the compression strength (σC) was found to be 38.0 KSI (standard devuation 3.02 

KSI). Similar results were found in strain capacity, with the mean tensile found to be 2.09

percent (standard deviation 0.219 percent) and the mean compression strain found to be 2.61

percent (standard deviation 0.467 percent).

Double Bias Lamina Behavior

The double bias fabric used in this test series consisted of two unidirectional layers of 6.27 

oz/yd2 each stitched together at +45° and -45° relative to the principle axis (0°), which is defined 

as the direction off the fabric roll. The layers are stitched together with a cotton thread running in 

the 0° direction (see figure 11). As there is an equal amount of reinforcement at each bias angle, 

it would be expected that properties at 0° and 90° would show to be from a common statistical 

population. This thought is supported by manufacturer data, which shows equal values for 

modulus of elasticity and strength in both directions. However, this type of behavior is not 

supported by the test data. Examination of the modulus and strength data shows significant 

difference at both 0° and 90° for tension and compression loadings.

Figure 11. Diagram. Structure of double bias laminate.

It is believed that the reason for the differences observed in the test data stems from the cotton 

thread used to hold the glass reinforcement fibers in position. Upon further examination it was 

found that significantly higher stiffness and strength were exhibited when the test direction was 

parallel to the direction of cotton stitching. Visual examination of the dry reinforcement 

supported this conclusion, with the fabric demonstrating far more distortion under loading 

perpendicular to the cotton than with loading parallel to the cotton threads.
30

The question in characterizing this lamina thus becomes which set of properties should be used 

when designing with double bias fabrics. It is worth noting that these fabrics are generally used 

to assist in carrying shear loadings in structures which reduce to principal tensile and 

compressive stresses parallel to the bias fiber direction. It is also worth noting that the fabrics are 

often laid down during fabrication without consideration of the cotton stitching. It is therefore 

thought that the best approach would be to neglect the effect of the cotton and use a conservative 

approach which characterizes the material based on the properties normal to the cotton direction. 

In this instance, this translates to the 90° direction.

Analysis of the tension and compression modulus of elasticity data at 90° indicates that the data 

are from a common statistical population. This translates to a combined modulus of elasticity of 

0.935 MSI (standard deviation 0.134 MSI) for the material. 

In-plane shear behavior was found to not be affected by the cotton stitching, and statistical 

analysis of the data in the 1-2 and 2-1 directions showed both sets of results to be from the same 

statistical population. The in-plane shear strength for the double bias lamina was found to be 

10.96 KSI (standard deviation 0.397 KSI).

CONCLUSION

Based on the outcomes of this testing, the values given in table 10 are suggested as design 

properties for the various lamina forms. The values were obtained using hand lamination and are 

not normalized for fiber content. This should be accounted for in design calculations and 

analysis. 

Additional care should be taken with using the capacity values. The values given are mean 

values, and appropriate statistical adjustment should be made using the associated standard 

deviations to ensure a sufficient margin of safety is created in design work.

Table 10. Suggested lamina design values for ply based design and analysis.
31

Modulus

E0 2340 KSI 329 KSI 935 KSI 134 KSI 1940 KSI 219 KSI 1070 KSI 118 KSI

E90 770 KSI 97 KSI

Ultimate Strength

Tension σT0 55.85 KSI 3.15 KSI 15.65 KSI 0.49 KSI 32.30 KSI 3.25 KSI 15.90 KSI 1.55 KSI

σT90 3.96 KSI 0.27 KSI

Compression σC0 48.32 KSI 1.71 KSI 12.41 KSI 0.32 KSI 38.00 KSI 3.02 KSI 21.18 KSI 1.31 KSI

σC90 11.45 KSI 1.40 KSI

Strain at Max. Stress

Tension εT0 2.46 % 0.14 % 10.01 % 1.16 % 2.09 % 0.219 % 1.96 % 0.303 %

εT90 0.62 % 0.06 %

Compression εC0 3.56 % 1.13 % 2.34 % 0.33 % 2.61 % 0.467 % 3.08 % 0.63 %

εC90 2.23 % 0.61 %

In Plane Shear Strength τ12 6.39 KSI 0.25 KSI 10.96 KSI 0.40 KSI 6.25 KSI 0.35 KSI 11.34 KSI 0.75 KSI

τ21 4.45 KSI 0.61 KSI

Short Beam Strength 40.00 KSI 1.83 KSI 33.00 KSI 2.51 KSI 33.00 KSI 2.51 KSI 21.70 KSI 4.74 KSI

Fiber Content (%) mass mf 40 % 36 % 47 % 35 %

volume vf 21 % 18 % 26 % 18 %

Thickness t 0.126 in 0.148 in 0.116 in 0.135 in

Mean Std. Dev.

Biaxial Lamina

Mean Std. Dev.

Property

Unidirectional 

Lamina

Double Bias Lamina Random Fiber (CSM) 

Lamina

Mean Std. Dev. Mean Std. Dev.
32

APPENDIX C: EVALUATION OF “AS-TESTED” PROPERTIES OF FRP LAMINATES

OVERVIEW

Based on earlier testing work, the researchers designed a trapezoidal profile for use in the bridge 

deck for this project. This profile would be produced using the pultrusion process. 

The pultruded combination (combi) tube was a three-cavity trapezoid, as shown in figure 12. The 

part uses a fire-resistant vinyl ester resin. The reinforcement is E-glass rovings, woven mat, and 

CSM. 

Figure 12. Diagram. Pultruded combination tube.

Figure 13 shows the laminate construction specified for the profile. The original trapezoid 

concept involved a constant 0.2-inch wall in all areas; however, it did not appear that adequate 

properties could be obtained with this concept. The final concept used a laminate of 0.2-inch 

horizontal walls and 0.24-inch walls for the inclined sides.
33

Figure 13. Diagram. Laminate construction for pultruded combination tube.

Predicted properties for this profile construction are given in table 11.

Table 11. Predicted properties of pultruded tube.

Property Unit Horizontal 

Walls 

Vertical 

Walls 

Thickness in 0.2 0.24

Fiber Volume Fraction % n/a n/a

Elastic Modulus – 0o (tension) MSI 3.39 3.18

Elastic Modulus – 90o (tension) MSI 2.33 2.39

In-Plane Shear Modulus MSI 0.74 0.75

Ultimate Tensile Strength – 0o KSI 63.6 55.6

Ultimate Tensile Strength – 90o KSI 20.6 22.3

Ultimate Compression Strength – 0o KSI 54.8 52.6

Ultimate Compression Strength – 90o KSI 22.3 23.6

Ultimate Shear Strength – In Plane KSI 8 8.6
34

The individual ply details of the laminate constructions for the horizontal and vertical walls are 

given in tables 12 and 13.

Table 12. Ply details for horizontal walls of pultruded tube.

Material Angle Areal Weight Thickness

oz / yd2 in.

1 1⁄2 oz CSM n/a 1.5 0.016

E-TTXM 2308

45 6.27 0.032

90 11.52

-45 6.27

CSM 8.10

Roving - 3.7 ends/in 0 38.3 0.038

E-TTXM 2308

45 6.27 0.032

90 11.52

-45 6.27

CSM 8.10

Roving - 3.7 ends/in 0 38.3 0.038

E-TTXM 2308

45 6.27 0.032

90 11.52

-45 6.27

CSM 8.10

1 1⁄2 oz CSM n/a 1.5 0.016

TOTALS 0 76.6 0.204

90 34.6

+45/-45 37.6

CSM 27.3
35

Table 13. Ply details for vertical walls of pultruded tube.

Material Angle Areal Weight, 

oz/yd2

Thickness, in.

1 1⁄2 oz CSM n/a 1.5 0.017

E-TTXM 2308 45 6.27 0.032

90 11.52

-45 6.27

CSM 8.10

E-TTXM 2308 45 6.27 0.032

90 11.52

-45 6.27

CSM 8.10

Roving – 7.6 ends/in 0 78.6 0.078

E-TTXM 2308 45 6.27 0.032

90 11.52

-45 6.27

CSM 8.10

E-TTXM 2308 45 6.27 0.032

90 11.52

-45 6.27

CSM 8.10

1 1⁄2 oz CSM n/a 1.5 0.017

TOTALS 0 78.6 0.240

90 46.1

+45/-45 50.2

CSM 27.3

Table 14 shows a comparison of the total weights of reinforcement used in each portion of the 

tube profile. 

Table 14. Areal reinforcement weights (oz/yd2

) of potential tube laminates.

Fiber Direction Creative 

Pultrusions 

Horizontal Wall

Creative 

Pultrusions 

Vertical Wall

0 76.6 78.6

90 34.6 46.1

+45/-45 37.6 50.2

CSM 27.3 27.3

Thickness 0.204 in. 0.240 in.
36

The bridge deck design called for a series of these trapezoidal profiles to be adhesively bonded 

together into a single panel unit which would form the deck. To ensure that individual units 

would not separate during service the bonded panel units were wrapped in an additional 

laminate. This outer laminate wrap also provided additional strength and stiffness to the panel. 

The specified configuration of this outer wrap was two layers of Knitmat S36007G fabric with a 

layer of Infusamat S1815CFM fabric in between the two layers. Knitmat S36007G is a stitchbonded biaxial fabric with 17.92 oz/yd2 of unidirectional reinforcement oriented at both 0° and 

90° for a total fabric weight of 35.84 oz/yd2. Infusamat S1815CFM is a biaxial fabric with 8.96 

oz/yd2 of unidirectional reinforcement oriented at both 0° and 90°. The biaxial layers are stitched 

to a 13.5 oz/yd2 layer of continuous filament mat (randomly oriented fiber). The fabric is 

designed specifically for resin infusion processes, with the continuous filament mat providing a 

medium to improve resin flow into reinforcement fiber during fabrication.

This appendix outlines testing conducted on these various laminates using test samples from the 

actual production environment. Samples of the trapezoidal tube were taken from the actual 

production run. The outer wrap laminates were prepared by XC Associates in their facility using 

production run materials and fabrication methods. 

TEST METHODS UTILIZED IN CHARACTERIZATION WORK

The test methods used in this characterization are outlined in table 15. These tests yield strength 

and modulus values in both primary directions (denoted as 0° for the primary fiber axis and 90°

for the direction normal to that axis). Properties are determined in both tension and compression. 

In-plane shear strength was also determined. The fiber content of each panel was also determined 

to allow proper comparison of the resulting properties from each laminate.
37

Table 15. Test methods used in characterization.

ASTM Test No. Title Properties Obtained Symbol

D3039/3039M-08 Standard Test Method for 

Tensile Properties of Polymer 

Matrix Composites

Ultimate tensile 

strength (0o) σ1T

Ultimate tensile strain 

(0o) ε1T

Modulus of elasticity 

(chord) (0o) E1T

Ultimate tensile 

strength (90o) σ2T

Ultimate tensile strain 

(90o) ε2T

Modulus of elasticity 

(chord) (90o) E2T

D6641/D6641M09Standard Test Method for 

Compressive Properties of 

Polymer Matrix Composite 

Materials Using a Combined 

Loading Compression (CLC) 

Test Fixture

Ultimate compression 

strength (0o) σ1C

Ultimate compression 

strain (0o) ε1C

Modulus of elasticity 

(chord) (0o) E1C

Ultimate compression 

strength (90o) σ2C

Ultimate compression 

strain (90o) ε2C

Modulus of elasticity 

(chord) (90o) E2C

D5379/D5379M05Standard Test Method for Shear

Properties of Composite 

Materials by the V-Notched 

Beam Method

In-plane shear strength 

(0-90)

τ12

In-plane shear strength 

(90-0)

τ21

D3171-09 Standard Test Method for 

Constituent Content of 

Composite Materials 

Test Method I, Procedure G: 

Matrix Burnoff in a Muffle 

Furnace

Fiber fraction - mass mf

Fiber fraction - volume vf

D2344/D2344M00Standard Test Method for ShortBeam Shear Strength of Polymer 

Matrix Composite Materials and 

Their Laminates

Short Beam Shear 

Strength
38

TEST RESULTS

Table 16 summarizes the results obtained from the trapezoidal tube through physical testing. 

Predicted values from the manufacturer are provided for comparative purposes.

Table 16. Summary of physical test data for tube laminate samples.

Table 17 summarizes the results obtained for the outer laminate wrap used to tie the individual 

tubes together into a single cohesive structural unit. Three different laminates were tested for this 

assessment. The first is a “witness panel” of the specified laminate prepared by XC Associates in 

their facility. The second is a sample of actual production laminate removed from a tested sample 

of bridge deck. The first two panels only possess glass fiber reinforcement. The third panel 

includes the layer of carbon which was added into the final construction to improve the overall 

stiffness of an unfilled panel.

Modulus

Tension ET0 3434 KSI 224 KSI 3180 KSI 4092 KSI 526 KSI 3390 KSI

ET90 2709 KSI 416 KSI 2390 KSI 1767 KSI 60 KSI 2330 KSI

Compression EC0 4178 KSI 515 KSI - KSI 3999 KSI 382 KSI KSI

EC90 3377 KSI 281 KSI - KSI 4157 KSI 465 KSI KSI

Ultimate Strength

Tension σT0 33.00 KSI 2.77 KSI 55.60 KSI 39.96 KSI 2.11 KSI 63.60 KSI

σT90 10.28 KSI 3.10 KSI 22.30 KSI 19.88 KSI 0.96 KSI 20.60 KSI

Compression σC0 54.12 KSI 7.35 KSI 52.60 KSI 70.00 KSI 8.08 KSI 54.80 KSI

σC90 37.50 KSI 1.48 KSI 23.60 KSI 54.73 KSI 7.49 KSI 22.30 KSI

Strain at Max. Stress

Tension εT0 1.01 % 0.13 % - % 1.07 % 0.09 % %

εT90 0.47 % 0.15 % - % 1.38 % 0.09 % %

Compression εC0 1.49 % 0.21 % - % 2.06 % 0.36 % %

εC90 1.32 % 0.26 % - % 1.43 % 0.28 % %

In Plane Shear Strength τ12 13.79 KSI 1.07 KSI 8.60 KSI 13.29 KSI 1.01 KSI 8.00 KSI

τ21 13.45 KSI 0.64 KSI KSI 15.55 KSI 1.11 KSI KSI

Fiber Content (%)

mass mf 74 % - % 72 % %

volume vf 53 % - % 51 % %

Thickness t 0.24 in 0.24 in 0.19 in 0.20 in

Mean Mean Std. Dev. Mean

Property

Combi-Tube Side Walls Combi-Tube Horizontal Walls

Tested Values Predicted 

Values Tested Values Predicted Values

Mean Std. Dev.
39

Table 17. Summary of physical test data from outer wrap laminate samples.

DISCUSSION OF RESULTS

Tube Performance

As can be observed from table 16, there were some significant discrepancies between the 

experimental obtained values for the tube walls and the predicted properties. The modulus values 

obtained are generally higher than the predicted values, and it is not expected that the extra 

stiffness will cause significant problems in the final structure. The biggest concern was in regard 

to the strength values, where a number of the test values are only about half of the predicted 

capacity. It is thought that this may be due to lower overall strain capacity for the tube compared 

with the type of strain limits normally expected for a unidirectional test laminate. Assuming a 

relatively linear stress-strain relationship for the material, the predicted values indicate an 

assumed failure strain in the order of 2 percent. From earlier testing in this project, the failure 

strains for lamina test panels were in generally excess of 2 percent, so this would seem to be a 

reasonable assumption. However, when the tube walls were tested, the maximum strain 

generated was only in the 1 to 1.5 percent range. Given that the behavior of these materials was 

highly linear up to failure, the lower strain limits translate to a lower strength capacity. The 

reason for the reduced strains in the fabricated tubes is unknown, and further testing would need 

to be undertaken to fully understand this behavior. As such testing is beyond the scope of work 

for this project, it is recommended that analysis of the deck behavior be done using the actual test 

data. 

Outer Wrap Performance

When comparing the “witness panel” for the outer wrap and the laminate sample removed from 

the actual deck panel, one would expect to see very similar test results. Observation of the data in 

table 17 shows that the data from the witness panel are consistently higher than the data for the 
40

other panel. Part of the reason for these differences is the difference in fiber volume fraction. The 

witness panel was prepared under idealized conditions as a small panel on a flat board. This 

enables the production of a better quality laminate with lower resin content. Working with the 

larger deck unit, where the laminate must be wrapped around the deck unit, it is harder to 

achieve the consolidation levels seen in the small panel. It is thought that the sample from the 

actual deck unit is more representative of the values which will be seen in the final deck.

CONCLUSION

The performance of the “as-tested” composite laminates differed from initial predictions. While 

preliminary design was performed using the predicted values, these actual test values were 

provided for final analysis computations and were shown to still provide sufficient performance. 

Ultimate validation of this performance was demonstrated in the testing of full-scale 

components.
41
42

APPENDIX D: GROUT SELECTION REPORT

OVERVIEW

The design solution selected for the replacement deck in this project utilizes an FRP profile with 

three cavities (see figure 14). These profiles will be bonded together to form a large deck unit. 

To improve the stiffness of the deck panel and to increase resistance to localized loading, the 

upper and lower cavities may be filled with an appropriate grout material. This grout may be 

used in either the upper or lower cavity or both. Development testing on the original design 

concept showed a significant increase in deck performance could be gained through use of the 

grout.

Figure 14. Diagram. Pultruded FRP combination tube

This appendix outlines work done to identify and select several grout products which may be 

suitable for use in the current design. Testing is performed to validate key selection parameters

and a final recommendation is made for the current project.

KEY ISSUES FOR THE GROUT

In assessing potential grout products for the application, the following issues were identified as 

important evaluation criteria:

• Compression strength.

• Workability.

• Cure shrinkage.

• Cure time.

• Adhesion to FRP substrate.
43

• Density.

• Cost.

• Industry acceptance.

SELECTION OF TEST MATERIALS

The strategy adopted for selecting an appropriate grout for this structure was to identify several 

potential grout options based on published data and technical documentation. 

There are two basic classes of grout which may be used for this design:

1. Cementitious grout

2. Polymer grout

Both classes were considered in this investigation.

The initial approach in identifying potential materials was to examine the approved material lists 

of several state DOTs for possible materials. Product manufacturers were then contacted to 

discuss the suitability of their product. Additional product recommendations from the project 

team and associated contacts were also considered. From these investigations the following 

products were identified as being potentially suitable for the current design:

• Target 1121 Cable Duct Grout, Non-shrink cement, Target Products Ltd.

• Target 1118 Unsanded Silica Fume Grout, Non-shrink cement, Target Products Ltd.

• Sikagrout 300 PT, Non-shrink cement, Sika Corporation

• Pro-Poxy 2000, Epoxy, DSC Unitex 

• Pro-Poxy 2500, Epoxy, DSC Unitex

• Ipanol E-Grout, Epoxy, IPA Systems, Inc.

• Ipanol E-Flex RM, Epoxy, IPA Systems, Inc.

SUMMARY OF PUBLISHED PERFORMANCE DATA

Table 18 provides performance information on the selected products, obtained from 

manufacturer data sheets.
44

Table 18. Published grout properties.

Product Type Set 

Time, 

hrs

Shrinkage 

(28 days), 

%

Compression Strength (ksi)

1 day 3 day 7 day 28 day

Target 1121 Cement 3 to 12 <0.2 2.56 4.43 8.10 12.20

Target 1118 Cement 8 exp: 1.5-

2.5

2.90 5.08 7.25 8.70

Sikagrout 

300PT

Cement 3 to 12 <0.2

exp: <2.0

3.00 5.00 7.00 8.00

Pro-Poxy 2000 Epoxy 0.3 to 4 0.005 - - - 14.50

Pro-Poxy 2500 Epoxy 0.5 - - - -

E-Grout Epoxy 1.5 0.005 11.00 15.00 15.00 15.00

E-Flex RM Epoxy 4 6.80

One of the difficulties in comparing manufacturer data for the cement grouts versus the epoxy 

grouts is that manufacturer testing is generally different for the two different types of material. 

Thus, the published data do not provide a straight comparison.

TESTING PROGRAM

In addition to examination of the manufacturer data, physical testing was conducted to obtain 

additional performance data required for finite element analysis modeling and to confirm 

published figures. The following tests were conducted:

• ASTM C109 / C109M - 11b Standard Test Method for Compressive Strength of 

Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens).

• ASTM C78 / C78M - 10 Standard Test Method for Flexural Strength of Concrete (Using 

Simple Beam with Third-Point Loading).

• ASTM C39 / C39M - 12 Standard Test Method for Compressive Strength of Cylindrical 

Concrete Specimens.

Compression modulus values were obtained using C39 with 3-inch by 6-inch cylinders.

Testing was conducted at 1, 3, 7, and 14 days for compression strength. Compression modulus 

and modulus of rupture (flexure) were determined at 14 days. Fourteen-day testing was used 

instead of the standard 28 days because this particular application requires materials with rapid 

strength development. Full strength development within 7 days is seen as preferable for this 

application.
45

TEST RESULTS

Table 19 summarizes the results obtained through physical testing.

Table 19. Results of grout testing.

Product Compression Strength (psi) Modulus of 

Rupture 

(psi)

Compression 

Modulus (ksi)

1 day 3 day 7 day 14 day 14 day 14 day

Target 1121 818 3154 6440 7448 834 952

Target 1118 - 6551 8221 8328 1218 983

Sikagrout 300PT 2275 6904 7644 8581 - -

Pro-Poxy 2000 9500 8092 - 11475 2099 -

Pro-Poxy 2500 - - - - 2040 743

Ipanol E-Grout 9293 14994 15206 15577 1900 -

Ipanol E-Flex RM 5979 7596 7751 6849 3773 -

OBSERVATIONS ON PHYSICAL TESTING

One of the key challenges of this particular application scenario is the need to flow the grout 

through a narrow (~1 inch) cavity over a distance of up to 24 feet. This requires a material with 

good flow characteristics. All of the cement grouts demonstrate highly fluid behavior once 

properly mixed. While they are initially paste-like, there is a point in the mixing process when 

the material changes to a highly fluid behavior. It is anticipated that in this state the cement 

grouts could be pumped or flowed into the cavity. 

The Pro-Poxy 2000 and Ipanol E-Grout are more viscous than the cement grouts but still exhibit 

enough flow where it is thought they could be successfully used in this application. It may be 

necessary to decrease the aggregate content of the E-Grout below the standard mix level to retain 

sufficient flow.

The Pro-Poxy 2500 is a mortar material rather than a grout and does not exhibit the flow 

characteristics required for this application. Therefore, it would not be suitable.

The resin component of the Ipanol E-Flex RM is considerably more viscous than the Ipanol EGrout resin. This results in a mix with reduced flow characteristics. While not as paste-like as the 

Pro-Poxy 2500, the E-Flex RM may present challenges in filling the pultrusion cavity. Further 

testing would need to be conducted on a full-length tube specimen to properly assess the 

suitability of this material.

Working time is a significant issue in grout selection, as sufficient time must be available to mix 

and place the material before cure occurs. This is not typically a problem with the cement grouts 

due to their much longer cure times. For the epoxy grouts, this is more problematic. Once the 

resin has gelled, further working of the material is not possible. The Pro-Poxy 2000 and Ipanol 

E-Grout both display longer working times compared with the Pro-Poxy 2500 and Ipanol E-Flex 

systems. For all systems it will be necessary to carefully stage the mixing of the grout, and 
46

multiple batches will be required to ensure the material going into a particular tube is as fresh as 

possible. It is thought that the working time of the Pro-Poxy 2000 and Ipanol E-Grout should be 

sufficient for the application at hand. TheE-Flex system appears to be a much faster gelling 

products and the short gel time available with typical batch sizes may cause problems with filling 

the tube.

As can be seen from the test data, the epoxy products have a significant performance advantage 

over the cement products both in terms of final strength and rapid development of that strength. 

It can be seen that the epoxy products develop around 80 percent of their ultimate strength within 

24 hours. This is a significant advantage in achieving the rapid production times envisaged for 

the bridge deck.

In terms of ultimate compression strength, the Pro-Poxy 2000 and Ipanol E-Grout display 

significantly higher strength than the cement grout options, with the Ipanol E-Grout exceeding 

15 ksi. As expected, the modulus of rupture for the epoxy options is approximately twice that of 

the cement grouts. 

While deflection under load was not measured, it was observed from the tests that the epoxy 

products deform significantly more than the cement grouts under failure load. The failure of the 

epoxy is also more progressive, rather than a sudden fracture. It is thought that this may make the 

epoxy products less susceptible to cracking in service, thereby preserving the integrity of the 

grouting in the tubes.

CONCLUSION

Table 20 shows an indication of the relative merits of the grouts, using a letter grade.

Table 20. Relative merits of grouts for the application (i.e., fill material).

Grout Adhesion Density Cost Industry 

Acceptance

ProPoxy 2000 A A C B

Ipanol E-Grout A A C B

Ipanol E-Flex A A C B

Target 1121 C B B A

Target 1118 C B B A

Sika 300PT C B B A

Based on the investigations undertaken and the testing performed, the project team elected to use 

Ipanol E-Grout for grouting the FRP tubes in the deck. The E-Grout provided high strength 

performance at a reasonable cost. It appears to offer the required handling characteristics and 

working time for filling the tubes. It develops strength rapidly allowing the manufacture of the 

deck to proceed after only 1 day of grout curing. Further testing of performance in full-size 

grouted tubes confirmed the suitability of this selection. This brand epoxy grout was chosen over 

others primarily because of availability.
47
48

APPENDIX E: TUBE TESTING REPORT

DESCRIPTION OF TESTED SPECIMENS

For this study, 10 empty (i.e., no grout) and 16 grouted FRP pultruded tubes were evaluate. The 

shape of the cross section is shown in figure 15. Overall dimensions and thicknesses were 

measured in nine specimens; see table 21. It appears that variability of the dimensions is in the 

order of 0.01 to 0.06 inches. 

Figure 15. Diagram. FRP tube cross section.

Table 21. Dimensions and thicknesses of FRP tubes (no grout).

Tube ID No. Weight

(lb)

Length

(inches)

t1

(inch)

t2

(inch)

t3

(inch)

t4

(inch)

t5

(inch)

t6

(inch)

t7

(inch)

W1

(inch)

W2

(inch)

H1

(inch)

#30 57.86 131.94 0.200 0.190 0.222 0.206 0.253 0.260 0.241 6.516 3.608 4.477

#31 57.86 131.91 0.200 0.195 0.230 0.208 0.251 0.252 0.248 6.519 3.620 4.478

#32 57.86 131.88 0.201 0.196 0.223 0.210 0.246 0.254 0.248 6.518 3.607 4.478

#33 58.08 132.09 0.201 0.201 0.224 0.207 0.252 0.253 0.241 6.521 3.594 4.482

#34 58.08 132.06 0.200 0.196 0.227 0.208 0.252 0.256 0.244 6.521 3.597 4.483

#35 57.75 131.84 0.200 0.196 0.231 0.210 0.245 0.256 0.245 6.515 3.599 4.477

#36 57.75 131.91 0.204 0.198 0.226 0.208 0.248 0.255 0.248 6.516 3.600 4.480

#37 57.86 131.91 0.203 0.195 0.223 0.207 0.248 0.254 0.250 6.518 3.604 4.482

#38 57.75 131.88 0.200 0.193 0.224 0.211 0.245 0.256 0.247 6.518 3.612 4.479

#00

(unlabeled) 56.87 131.41 0.203 0.197 0.230 0.196 0.242 0.255 0.239 6.519 3.566 4.474

Average 57.77 131.88 0.201 0.196 0.226 0.207 0.248 0.255 0.245 6.518 3.601 4.479

Max 58.08 132.09 0.204 0.201 0.231 0.211 0.253 0.260 0.250 6.521 3.620 4.483

Min 56.87 131.41 0.200 0.190 0.222 0.196 0.242 0.252 0.239 6.515 3.566 4.474

Range 1.210 0.68 0.004 0.012 0.009 0.016 0.012 0.008 0.012 0.006 0.054 0.008

Of the 16 grouted tubes, half were filled with a cementitious grout and the other half filled with 

an epoxy grout. Two different grouting configurations were explored: “wide” or “narrow” cells 

filled. Two different cross section positions were also evaluated: wide side up and wide side 

down. Figure 16 shows all four possible combinations. The specimens were also checked for 

dimensional stability, weight, and any visible defects. One specimen, #69, had a lower weight 

than similar specimens; the manufacturer indicated that it was partially filled with epoxy grout.

Specimens were received on February 2, 2012.
49

Figure 16. Diagram. Grout configurations.

Table 22. Details of FRP grouted tubes.

Tube ID No. Grout type Cell filled Weight(lbs) Length(in) Date filled cross-section check

Height H1 Width W1

#68-EW Epoxy 2.5 Wide 109.6 132.06 1/31/2012

#69-EW Epoxy 2.5 Wide *91.6 132.00 Partially filled 4.462 6.523

#50-EW Epoxy 2.5 Wide 111.4 132.25 1/31/2012 4.470 6.522

#51-EW Epoxy 2.5 Wide 111.0 132.13 1/31/2012

#52-EN Epoxy 2.5 Narrow 88.4 132.25 1/31/2012

#53-EN Epoxy 2.5 Narrow 88.0 132.13 1/31/2012

#54-EN Epoxy 2.5 Narrow 88.6 132.28 1/31/2012 4.478 6.513

#55-EN Epoxy 2.5 Narrow 89.2 132.13 1/31/2012 4.474 6.514

#56-CW cementitious Wide 104.2 132.19 1/20/2012

#57-CW cementitious Wide 104.0 132.00 1/21/2012

#58-CW cementitious Wide 103.8 132.00 1/22/2012 4.476 6.520

#59-CW cementitious Wide 104.2 132.06 1/23/2012 4.473 6.511

#60-CN cementitious Narrow 84.8 132.00 1/24/2012

#61-CN cementitious Narrow 84.8 132.25 1/25/2012

#62-CN cementitious Narrow 85.0 132.13 1/26/2012 4.476 6.522

#63-CN cementitious Narrow 85.0 132.19 1/27/2012 4.471 6.516

DESCRIPTION OF TEST SETUP

The FRP tubes were tested under three-point loading (hydraulic actuator at midspan). Steel 

rollers were used for support between a 10-foot span length. Vertical deformation was measured 

using one linear variable differential transformer (LVDT) and/or string pot. In some specimens, 

strain measurements were obtained from uniaxial and rosette strain gage configurations. Two 

load cells were used to collect load data (22-kip or 110-kip capacity). The 22-kip load cell was 

used in nondestructive tests to better monitor the low-range of load, whereas the 110-kip load 

cell was used when the tubes were tested up to failure. A steel plate (12 inches by 4 inches by 0.5 

inches) was used under the hydraulic actuator to create a 4-inch-wide distributed load over the 

FRP specimen. 
50

Figure 17. Photo and diagram. Testing setup.

22-kip load cell 110-kip load cell

Figure 18. Photos. Load cells used for FRP testing.

TEST PROGRAM

FRP Tubes with No Grout

All 10 FRP tubes with no grout were tested using the test setup described above. Two of them 

were tested up to failure, and the remaining eight were loaded and unloaded in the elastic range 

with two different cross section positions (wide side up, WSU, and wide side down, WSD), to 

check for any changes in their elastic stiffness response. The FRP tube #38 was initially loaded

elastically up to 2.5 kips, and then was loaded up to failure (WSU). Specimen #30 was 

instrumented with strain gages in three locations: top (SG1) and bottom (SG2) “flange” under 

point load, and shear span (SG 3-5) at 25.4 inches from point load. This specimen was tested to 
51

failure (WSU). Figure 19 shows the strain gages locations. Table 23 provides additional details 

on this test program.

Figure 19. Diagram. Strain gage locations for the FRP tube specimen #30.

Table 23. Test program—FRP tubes no grout. Tube ID 

No.

Instrumentation used in 

test

Cross-section 

position

Max or Failure 

Load (kips)

Displacement at max 

or failure load (inch)

Flexural stiffness 

k (lbs/inch) 

Tested 

date

#00 

(unlabeled) LVDT & 22 kips load cell WSU 2 1.36 1419 11/22/2011

WSD 1.38 1418 11/22/2011

#30

LVDT & 22 kips load cell &

strain_pot & 2 strain

gages & 1 strain rosette

WSU 5(fail)

crushing at top 3.72 1520 12/19/2011

#31 LVDT & 22 kips load cell WSU 2.5 1.64 1527 01/04/2012

WSD 1.65 1546 02/02/2012

#32 LVDT & 22 kips load cell WSU 2.5 1.67 1525 01/04/2012

WSD 1.67 1542 02/03/2012

#33 LVDT & 22 kips load cell WSU 2.5 1.65 1541 01/05/2012

WSD 1.66 1547 02/03/2012

#34 LVDT & 22 kips load cell WSU 2.5 1.67 1528 02/03/2012

WSD 1.64 1551 01/05/2012

#35 LVDT & 22 kips load cell WSU 2.5 1.68 1518 02/03/2012

WSD 1.65 1534 01/05/2012

#36 LVDT & 22 kips load cell WSU 2.5 1.68 1522 02/03/2012

WSD 1.64 1543 01/05/2012

#37 LVDT & 22 kips load cell WSU 2.5 1.67 1519 01/06/2012

WSD 1.65 1539 01/06/2012

#38

LVDT & 22 kips load cell WSU 2.5 1.66 1529 02/03/2012

WSD 1.66 1533 02/03/2012

LVDT & 110 kips load cell WSU 4.5(fail)

crushing at top 3.49 1468 02/14/2012

The load-deflection behavior of FRP empty tubes is shown in figure 20. Results indicate that the 

flexural stiffness (k; calculated as the slope between 300 and 2,000 lb) of the FRP tubes #31-#38 

is very similar: k =1533 lb/inch (on average) with a 1.2 percent variation. The flexural stiffness 

of the FRP tube #00 empty tube is 7 percent smaller: k=1419 lb/inch, possibly related to the 

smaller tube thickness (table 21 shows that the thickness of the walls, e.g. t4, t5, t7, of this tube is 

smaller than the other specimens). Flexural thickness values are tabulated in table 23. 

Strain data from the test to failure of FRP tube #30 shows that the strain gage on the bottom 

“flange” (SG2) ha as a quite linear response up to failure load . By contrast SG1, near the top 

flange exhibited a nonlinear response beyond 4,000 lb of applied load. The strain gage rossette 

(SG3-5) displayed a very small magnitude of strain values, as expected.
52

Figure 20. Graphs. Load-deflection elastic response of FRP tubes with no grout (left); Loaddeflection response up to failure (tubes #30 and #38) (right).

Figure 21. Graph. Load-strain response of FRP tube #30 (no grout, WSU).

The FRP tubes with no grout (#30 and #38, both WSU) failed by crushing of the top flange 

under the point load. Figure 22 shows photographs of these specimens after failure.

Specimen #30 Specimen #38

Figure 22. Photos. Failure modes of FRP tubes with no grout.
53

Grouted Tubes

Fifteen grouted tubes were tested using the same test setup described above; the FRP tube 

partially filled with grout (#69) was not tested. The tested specimens had two different grouts 

and two different grouting configurations. Table 24 shows the details of this test program, 

including position of the cross section, instrumentation used, failure loads, displacements and 

modes. Flexural stiffness was calculated between two load levels in the elastic range (prior to 

first crack). Because each specimen’s load range is different, this information has been included 

in table 24.

Only four specimens were tested to failure (FRP tubes #50, 52, 57, and 60). The remaining 

specimens were loaded and unloaded in the elastic range. Figure 23 shows the load-deflection 

curves of all FRP tubes (with and without grout) tested to failure. It should be noted that the 

grouted tubes had a higher flexural stiffness than the empty tubes. Epoxy grouted specimens had 

a higher flexural stiffness than cementitious grouted specimens. 

Table 24 shows that the elastic flexural stiffness of epoxy grouted tubes is 34 percent larger, on 

average, than that of the non-grouted tubes, while the flexural stiffness of cement-based grouted 

tubes is only 18 percent larger than that of the non-grouted tubes. When the cementitious grout is 

in compression, the flexural stiffness of the grouted tube is 17 percent larger than that of the 

grouted tube where the cementitious-based grout is in tension, which in turn has a very small 

increment of stiffness over the empty tube condition. However, for epoxy grouted tubes, the 

elastic flexural stiffness has little variation (only 4 percent) whether the grout is subjected to 

compression or tension. Comparing the effect of grouting either the wide or narrow cell, the 

epoxy grouted tubes have a 9 percent larger elastic flexural stiffness when the narrow cell is 

filled (as opposed to the wide cell); the cement-based grouted tubes show little difference.

Specimen #56 had the lowest flexural stiffness (1,600 lb/in.). Analysis of the load-deflection

curve indicates that the composite action in this tube vanishes at a very small load, and the 

specimen behaves as an empty tube. Figure 24 shows a comparison of the load-deflection 

behavior (in the elastic range) for specimen #56, #57 (similar configuration), and #31 (empty 

tube).
54

Table 24. Test program—grouted FRP tubes.

Tube ID

No.

Instrumentation 

used

Cross-section 

position

Max or 

failure 

Load(kips)

Deflection at 

max or failure 

load (inches)

Elastic 

stiffness

(lbs/inch)

[load

range, lbs]

Load and 

deflection at 

first crack 

(kips/inches)

Tested 

date

#68-EW String pot &

22 kips load cell WSD 3.5 2.05 1926[300-2550] 2.55/1.319 03/02/2012

#50-EW String pot &

110 kips load cell WSU

9(fail)

Failure at 

bottom

4.92 1920

[300-4500]

No crack sound 

heard 02/24/2012

#51-EW

LVDT &

22 kips load cell & 2 

strain gages & 

1 strain rosette

WSU 7.3 3.89 1993

[300-3500]

No crack sound 

heard 03/03/2012

#52-EN String pot &

110 kips load cell WSD

9.6(fail)

Failure at

bottom

4.77 2234

[300-4800]

No crack sound 

heard 02/24/2012

#53-EN

LVDT &

22 kips load cell & 2 

strain gages

WSD 7.8 3.84 2182

[300-3900]

No crack sound 

heard 03/03/2012

#54-EN String pot &

22 kips load cell WSU 3.8 2.41 2048[300-1590] 1.59/0.756 03/02/2012

#55-EN String pot &

22 kips load cell WSU 1.8 0.92 2045[300-1750] 1.75/0.838 03/02/2012

#56-CW

LVDT &

22 kips load cell & 2 

strain gages & 

1 strain rosette

WSU 5.9 3.89 1600

[300-3000]

No crack sound 

heard 03/03/2012

#57-CW

LVDT &

22 kips load cell

WSU 2.5 1.42 1970

[300-2000] 2/1.015 02/03/2012

WSD 1.68 0.4/0.242

LVDT &

110 kips load cell WSU

6.44(fail)

Failure at 

bottom

4.39 02/14/2012

#58-CW String pot &

22 kips load cell WSD 3.8 2.58 1728[30-400] 0.4/0.221 03/02/2012

#59-CW LVDT &

22 kips load cell WSD 1.0 0.68 1687[30-420] 0.42/0.244 03/02/2012

#60-CN String pot &

110 kips load cell WSD

7.5(fail)

Failure at 

bottom

4.60 2103

[300-3000] 3/1.431 02/24/2012

#61-CN

LVDT &

22 kips load cell & 2 

strain gages

WSD 8.0 5.39 1850

[300-3000] 5.98/3.654 03/03/2012

#62-CN String pot &

22 kips load cell WSU 3.8 2.63 1646[30-300] 0.3/0.174 03/02/2012

#63-CN LVDT &

22 kips load cell WSU 1.0 0.66 1714[30-360] 0.36/0.205 03/02/2012
55

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.

Four specimens were instrumented with strain gages. FRP tubes #53 and #61 had one strain gage 

at the top (SG1) and one at the bottom (SG2). FRP tubes #51 and #56 had, in addition to SG1 

and SG2, a strain gage rosette (SG3-5) at 25.4 inches from the point load. Figure 19 shows

locations of all the strain gages. Load-strain plots are show in figure 25. The two strain gage 

rosettes (FRP tubes #51 and #56) failed during testing, perhaps due to insufficient curing time of 

the adhesive used prior to test. Strain responses of these specimens confirm the load-deflection 

behavior, analyzed previously, showing that grouted tubes have a larger section modulus when 

the narrow cell is filled and subjected to compression. Epoxy grouted tubes have a larger section 

modulus than cement-based grouted tubes.
56

Specimen #51-EW-WSU Specimen #53-EN-WSD

Specimen #56-CW-WSU Specimen #61-CN-WSD

Figure 25. Graphs. Load-strain responses of grouted FRP tubes.

Failure mode for the grouted tubes originated with a tensile rupture of the bottom flange, 

regardless of the location of the grout (wide or narrow cell in compression). Cracks propagated 

vertically for all specimens, and also horizontally in specimen #50 (the location of this horizontal 

crack is 0.5 inches from the bottom, apparently at the splice between wall tube and the bottom 

horizontal section of the FRP tube). Figure 26 shows photographs of the damage regions for all 

four tested specimens.
57

Specimen #50- EW-WSU Specimen #52-EN-WSD

Specimen #57-CW-WSU Specimen #60-CN-WSD

Figure 26. Photos. Photographs of failure modes of grouted FRP tubes.

Specimen #60 also showed slip of the cementitious grout (top) during testing at one of the ends 

of the specimen (the other side was covered by the manufacturer with tape), indicating that the 

bond between the grout and the FRP tube had failed. The load-deflection curve has a significant 

load drop around 3,000 lb, probably related to the debonding initiation. Load-strain curves for a 

cementitious-grouted specimen also registered a significant load drop, in this case around 6,000 

lb.

Figure 27. Photos. Cementitious grout slipping at the end of FRP tube #60.
58

After testing to failure, specimens #50 and #57 were cut using a wet cutting block saw near the 

damaged region (around the center span) to look in detail at the debonded region. Inspection of 

the cut surfaces shows that debonding between the epoxy grout and the FRP tube (specimen #50) 

occurred along the lower interface, whereas cracks between the cementitious grout and the FRP 

tube (specimen #57) were present along the top interface, as shown in figure 28. Specimen #37 

also had a vertical crack inside the cementitious grout, a possible indication of additional damage 

on this grouted region.

Specimen #50- EW-WSU Specimen #57-CW-WSU

Figure 28. Photos. Cross sections of grouted tubes near midspan, after failure.

CONCLUSIONS

Based on the experimental program developed, the following conclusions can be drawn:

• Simple load-deflection tests of nine empty tubes show that the empty tubes have similar 

flexural stiffness (k=1533 lb/inch) with a 1.2 percent variation. Only one tube had a 

smaller stiffness, probably due to smaller FRP tube thicknesses.

• Test results show that grouted tubes have a larger elastic flexural stiffness than empty 

tubes. Epoxy grouted tubes have 34 percent greater stiffness, while cement-based grouted 

tubes have only 18 greater stiffness than empty tubes.

• For cement-based grouted tubes, the increase in the elastic flexural stiffness is only 

significant when the grout is in compression, whereas for the epoxy grouted tubes, the 

increase on flexural stiffness is present regardless of the grout being in compression or 

tension.

• Failure mode of the empty tubes is by FRP crushing at the top flange, while the grouted 

tubes (grout in compression) fail by tensile rupture of the bottom flange.

• Inspection of the damaged regions of the grouted specimens tested to failure shows that 

debonding occurred at the interface between the FRP and the grout. This occurred at load 

levels that ranged from 40 to 80 percent of the maximum load.

• The cementitious grout appears to have a lower tensile and bond strength, which could be 

easily cracked during field installation.
59
60

APPENDIX F: STRUCTURAL PANEL TEST REPORT

DESCRIPTION OF TESTED SPECIMENS

Twelve panels, each composed of seven FRP tubes, were evaluated for this project. Eleven 

panels were delivered on May 16, 2012, and one additional panel was delivered 2 weeks later. 

Panels #1 to #4 were empty (i.e., no grout); manufacturing details are listed in figure 29.

Figure 29. Specifications with photos. Manufacturing details of panels without grout.

Panels #5, #6, #9, and #10 were filled with epoxy grout; panels #7, #8, #11, and #12 were filled 

with cementitious grout. Two different grouting configurations were provided: “alternate” or 

“narrow side” cells filled. Two different cross section positions were tested: WSU and WSD. 

Figure 30 shows all four possible combinations. Specimen details are listed in table 25.
61

Figure 30. Diagram. Grout configurations.

Table 25. Details of panels.

Panel ID No. Grout type Cell filled Length(in) Width Height(in.) Date received Wide side(in.) Narrow side(in.)

#1 No none 132.50 38.50 35.50 4.81 05/16/2012

#2 No none 132.88 38.50 35.38 4.88 05/16/2012

#3 No none 132.13 38.31 35.25 4.75 05/16/2012

#4 No none 132.81 38.25 35.19 4.81 05/16/2012

#5-EN Epoxy Narrow side 132.81 38.00 35.13 4.88 05/24/2012

#6-EA Epoxy Alternate 132.50 38.25 35.13 4.94 05/16/2012

#7-CA Cementitious Alternate 132.75 38.19 35.13 4.81 05/16/2012

#8-CN Cementitious Narrow side 132.19 38.19 35.25 4.88 05/16/2012

#9-EN Epoxy Narrow side 132.69 38.13 35.19 5.00 05/16/2012

#10-EA Epoxy Alternate 132.56 38.13 35.13 4.81 05/16/2012

#11-CA Cementitious Alternate 132.81 38.13 35.13 4.88 05/16/2012

#12-CN Cementitious Narrow side 132.63 38.00 35.13 4.75 05/16/2012

DESCRIPTION OF TEST SETUP

The FRP panels were tested under three-point loading (hydraulic actuator at midspan). Steel 

rollers were used for support between a 10-foot span length. A 110-kip load cell was used to 

collect load data. The test setup is shown in figure 31.

For the empty panels, the vertical deformation was measured using one LVDT and one string pot

at the midpoint of the bottom plane. An I-shape steel beam (4-inch by 35-inch contact area) was 

used under the hydraulic actuator to create a 4-inch-wide distributed load over the FRP 

specimen.

For the grouted panels, the vertical deformation was measured using one string pot at the 

midpoint of the bottom plane and two LVDTs placed 15 inches from the string pot, as shown in 

figure 32. A steel tube measuring 4 inches by 4 inches by 0.375 inches was used under the point 

load. The contact area of this steel tube is 2.75 inches multiplied by the width of the top plane

(35 inches for WSD and 38 inches for WSU). 

In some specimens, strain measurements were obtained from uniaxial and rosette strain gage 

configurations. 
62

Front view of test setup

Side view of test setup

Figure 31. Photos and diagrams. FRP panel test setup.

Bottom view of test setup (panels #1-#4) Bottom view of test setup (panels #5-

#12)
63

Figure 32. Diagrams. Strain gage location for panel #4.

TEST PROGRAM

FRP Panels with No Grout

The panels with no grout were tested using the test setup described above. They were all loaded 

and unloaded in an elastic range (up to 20 kips). Panel #1 was tested both WSU and WSD. Panel 

#2 was tested WSD. Panel #3 was loaded and unloaded (up to 20 kips), then tested to failure. It 

was instrumented with two strain gages installed at the centerline of the panel width. SG1 was 

placed at midspan on the bottom surface; SG2 was attached 2.125 inches away from midspan on 

the top surface; see figure 33. Panel #4 was instrumented with one strain gage at midspan and 

centerline of the panel width on the bottom surface. Table 26 provides additional details on this 

test program.

Figure 33. Diagrams. Strain gage location for panel #3 (tested to failure).

Table 26. Test program—FRP panel without grout.

Panel ID 

No. Instrument used Cross-section position

Max or Failure 

Load(kips)

Displacement at max or 

failure load (in.)

Flexural 

stiffness k 

(kip/in.) 

Tested 

date

#1 String pot & LVDT &

110 kips load cell

WSU 20 1.38 14.49 05/23/2012

WSD 1.39 14.4 05/23/2012

#2 String pot & LVDT &

110 kips load cell WSD 20 1.37 14.72 05/22/2012

#3

String pot & LVDT &

110 kips load cell WSD

20 1.44 14.32 05/22/2012

String pot & 110 kips load 

cell & 2 strain gages

61(fail)

crush at top 4.45 13.91 05/24/2012

#4

String pot & LVDT &

110 kips load cell & 1 

strain gage

WSD 20 1.4 14.05 05/22/2012
64

The load-deflection behavior of all FRP empty panels in the elastic range (up to 20 kips) is 

shown in figure 34 (left). Flexural stiffness, k, was calculated as the slope between 1 and 10 kips 

(except for panel #3). Results indicate that panels #1 through #4 have a very similar stiffness:

average k =14.32 kip/inch, with a 2.9 percent variation. Panel #3 exhibited a change in stiffness 

around 3 kips of load. This is a very small change, possibly due to very localized damage on the 

panel, though this was not observed visually. Flexural stiffness was calculated between 5 and 15 

kips (k = 14.32 kip/inch, as shown in table 26).

Strain data from the test of panel #4 has a linear response up to 20 kips of load; see figure 35 

(left). Strain data from panel #3 are is illustrated in the graph on the right in figure 35. This 

shows that the strain gage on the top (SG2) behaves quite linearly, whereas SG1, located at the 

centerline and mid-width of the panel (bottom), exhibited a nonlinear response beyond 40 kips of 

applied load. Strain behavior during unloading of the specimen after failure is shown with dotted 

lines.

a ) elastic response of all FRP panel-no grout b) response to failure of panel #3

Figure 34. Graphs. Load-deflection response of FRP panels with no grout.

a ) Load-strain response of panel #4 b) Load-strain response of panel #3

Figure 35. Graphs. Load-strain response of FRP panels with no grout.
65

Panel #3 was loaded manually under displacement control. The first crack was heard around 32 

kips. Additional cracking noises were heard with incremental loading, and they seemed to come 

from localized damage regions. At around 62 kips and 4.5 inches of deflection, a significant 

cracking noise was heard. It appears that one or more of the FRP tubes failed (compression at the 

top layer), and additional sounds were heard (the load dropped to around 52 kips). At this point, 

it was observed that the top of the outer wrap buckled in the vicinity of the steel tube. The test 

continued under increasing displacement, and after just few more major cracking sounds, the 

load dropped to around 15 kips (perhaps all the FRP tubes had failed at this point). The outer 

wrap showed a region of damage near the point load. The specimen was unloaded at this point. It 

was observed that very small permanent deformation (0.5 inches) remained after the specimen 

was fully unloaded. Residual strain values were also determined: SG1 (bottom) registered 0.07

percent, and SG2 (top) registered 0.18 percent of permanent deformation. Figure 36 shows the 

sequence of events.

Failure at midspan: buckling of outer wrap Top surface of the damaged outer wrap

Figure 36. Photos. Failure sequence of FRP panel #3 (no grout).

Figure 37 shows photographs of the cross section of panel #3 after failure. The failed panel was 

cut into two pieces along the width using a mansory blade, close to the damaged region. It 

appears that where the outer wrap buckled, the bond between the FRP tubes and the outer wrap 

was not strong. This may indicate that the tube surfaces may need better surface preparation, 

such as sanding. By contrast, visual inspection could not detect cracks betweeen the individual 

FRP tubes. In the future, nondestructive evaluation methods, such as acoustical emmission, could 

be used to investigate the possibility of damage. The top surface of the FRP plates was then 

exposed, and the compression cracks along the top section of the FRP tubes were photographed.

Four pieces of the outer wrap were obtained by additional cuts along the top surface of the FRP 

panel and were sent to a laboratory to determine “as-built” properties of the laminate. The 

laminate was tested in tension, compression, and shear to compare with previous test results. 

Fiber fraction was also determined.
66

Cutting of the FRP panel #3 Cross section of panel #3 near damage 

region

Compression cracks on top of FRP tubes Craking detail-top surface FRP tubes

FRP panel #3- cut lines

Figure 37. Photos and diagrams. Details of cut sections from panel #3.

Grouted Panels

Eight FRP grouted panels were tested using the same test setup as used for the non-grouted 

panels. The tested specimens had two different grouts and two different grouting configurations.

Table 27 shows the details of this test program, including the position of the cross section, 

instrumentation used, and maximum loads and displacements. Flexural stiffness was calculated 

between two load levels in the elastic range (prior to first crack). Because each specimen’s 

elastic range is different, this information has been included in table 27. Panels #5, #8, #9, and 
67

#12 were loaded and unloaded to 20 or 22 kips and then to 38 kips; panels #6, #7, #10, and #11 

were loaded and unloaded to 24 kips and then to 40 kips. Deformation of the FRP panel was 

recorded using two LVDTs and one string pot. No significant difference (in the order of 3.2 

percent) was found between the deflections at the centerline vs. the edge. 

Table 27 shows that the elastic flexural stiffness of the cementitious grouted panels is very 

similar—k= 15.24 kip/inch, on average—regardless of the location of the filled cells and tested 

position. This k value is only 6.4 percent higher than for the panels without grout. The flexural 

stiffness of the epoxy grouted panels (filled in alternate cells) is 45 percent larger, on average, 

than that of the non-grouted panels; the flexural stiffness of the epoxy grouted panels (narrow 

side cells filled) is 26 percent larger than that of the non-grouted panels. Thus, the epoxy grouted 

panels with alternate cell filled are the most efficient panels with respect to flexural stiffness in 

the elastic range. Figure 38 shows the different load-deflection response of the grouted panels in 

the elastic range and overall response between epoxy grouted panels (filled with alternate cells 

and narrow side cells) and a cementitious grouted panel. Non-grouted (empty) panel response is 

also included for completeness.

The residual deformation data (after the last unloading cycle) is shown in table 27. The average 

residual deformation of the cementitious grouted panels was found to be 0.06 inches, while the 

average residual deformation of the epoxy grouted panels is 0.125 inches. It was noted that for 

panel #5 (epoxy grouted-EN), no cracking was heard during the loading portion of the test; this 

panel exhibited the smallest permanent deformation of all epoxy grouted panels.

Table 27. Test program—grouted FRP panels.

Panel 

ID No. Instrument used

Crosssection 

position

Max

Load(kips)

Displacement 

at max loads

(inch)

Flexural 

stiffness

(kip/in.)

[load range, 

kip]

Load and 

deflection at 

first crack 

(kips/in.)

Average 

residual 

deformation

(inch)

Date 

tested

#5-EN String pot & 2 LVDT & 

110 kips load cell WSD 20&38 1.21&2.09 17.94[1-10]

No crack 

sound heard 0.05 05/31/2012

#6-EA String pot & 2 LVDT & 

110 kips load cell WSU 24&40 1.29&2.28 20.91[1-10] 10.8/0.529 0.129 06/05/2012

#7-CA

String pot & 2 LVDT & 

110 kips load cell & 2 

strain gage & 2 strain 

rosette

WSD 24&40 1.53&2.63 15.58

[1-6.5] 6.7/0.429 0.061 06/04/2012

#8-CN String pot & 2 LVDT & 

110 kips load cell WSU 20&38 1.42&2.73 15.07[0.5-3] 3.2/0.219 0.074 05/30/2012

#9-EN String pot & 2 LVDT & 

110 kips load cell WSU 22&38 1.34&2.60 18.09[1-10] 13.9/0.786 0.171 05/31/2012

#10-EA

String pot & LVDT &

110 kips load cell & 2 

strain gages & 2 strain 

rosette

WSD 24&40 1.27&2.29 20.72

[1-10] 19/0.931 0.151 06/04/2012

#11-CA String pot & 2 LVDT & 

110 kips load cell WSU 24&40 1.50&2.57 15.02[1-5] 5.3/0.337 0.056 06/04/2012

#12-CN String pot & LVDT &

110 kips load cell WSD 22&38 1.36&2.36 15.29[1-4] 4.2/0.274 0.047 05/30/2012
68

a) Elastic response of FRP panels b) Overall response up to 20 kips of FRP 

panels

c) Grout effect on alternate filled cell 

configuration 

d) cementitious grout effect on FRP panels

Figure 38. Graphs. Load-deflection response of FRP grouted panels.

The elastic flexural stiffness of the epoxy grouted panel is 36 percent larger than that of the 

cementitious grouted panel. However, cracking of the epoxy grout beyond 20 kips of applied 

load significantly affect the stiffness of the panel, as shown in the graph at the bottom left in 

figure 38. With increasing loading, the flexural stiffness drops to 16 kip/inch at the load range of 

25 to 35 kips, which is only 7 percent larger than the cementitious grouted panel (k=14.9 

kip/inch) measured at the same load range. The graph at the bottom right of figure 38 shows that 

even thought the position of the cementitious grout does not affect the flexural stiffness of the 

FRP panels on the elastic range (before first cracking), it does affect the load-deformation 

behavior in the cracked region.

Two grouted panels (#7 and #10) were instrumented with strain gages (uniaxial and rosette

configuration). Panel #7 has one strain gage at the top (SG1), one strain gage at the bottom 

(SG2), and two strain gage rosettes on each side (SG3-5, SG6-8). Panel #10 has one strain gage 

at the top (SG1), one strain gage at the bottom (SG2), and one strain rosette on the front side

(SG3-5). Strain gage positions are shown in figures 39 and 40.
69

Figures 41 through 43 show load-strain plots. Figure 43 shows a comparison of the strain 

behavior at the top and bottom of the FRP panels #7-CA and #10-EA. Up to a load of 20 kips, 

the strain-load curves for SG1 (top) and SG2 (bottom) look quite symmetrical for both panels. 

Beyond 20 kips, the epoxy grouted panel (#10-EA) cracks in tension (SG2); in contrast, SG1 

doesn’t show any disturbance. SG2 in panel #10 has a similar response as SG2 for panel #7 

(cementitious grout-CA). 

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.
70

Figure 42. Graph. Load-strain plot of FRP panel #10-EA.

Figure 43. Graph. Load-strain (top & bottom) FRP panels.

CONCLUSIONS

Based on the experimental program developed, the following conclusions can be drawn:

• Load-deflection test of four FRP panels without grout shows that they have similar 

flexural stiffness (k=14.32kip/inch, with a 2.9 percent variation).

• The flexural stiffness of the epoxy grouted panels (filled in alternate cells) is 45 percent

larger, on average, than that of the non-grouted panels, whereas the epoxy grouted panels 

with cells filled on the narrow side only have a 26 percent increase. 

• The cementitious grouted FRP panels only showed an increase of 6.4 percent of flexural 

stiffness when compared to the empty panels. Very little effect was observed from 

changes in the location of the filled cells and/or tested position. 

• The higher flexural stiffness of the epoxy grouted panels significantly decreases when the 

grout (or bond between grout and FRP tube) cracks, around 20 kips. Post-cracking 

stiffness value approaches that of the cementitious panels. 

• Even thought the position of the cementitious grout does not affect the flexural stiffness 

of the FRP panels on the elastic range (before first cracking), it does affect the loaddeformation behavior in the cracked region.

• Strain data show that the epoxy grouted FRP panel with alternate cells filled has grout 

cracking (or bond failure) in the tension region at a 20-kip load level. 
71

• Although both grouts achieved fairly highly strength within a short time, the epoxy grout 

is preferred because of the apparent better bond between it and the FRP surface. Further 

information about the grouts can be found in Appendix D.
72

APPENDIX G: PANEL SHEAR TEST

XC Associates fabricated small panels (42 inches long by 17 inches wide) by joining three FRP 

pultruded tubes and wrapping them with glass fiber wrap (three layers). These specimens were 

initially designed to evaluate the bond between two adjacent pultruded tubes; however, the wrap 

was too stiff to be deformed with the test setup available at Penn State to the load level needed to 

break the bond between the tubes. 

The researchers requested a different type of test to evaluate the deformation of one panel 

between two steel sections with the same top flange width (8 inches) and spacing (24 inches) as 

the steel girders in the demonstration bridge. The test setup will evaluate the effect of two 

different load footprints: 20 inches by 10 inches (AASHTO tire contact area) and 6 inches by 6 

inches (simulating the effect of a smaller footprint due to debris on the road). In both tests, the 

panel was loaded up to 25 kips. Deformation was measured from the actuator, as well as a string 

pot (midspan under panel) and LVDT (top surface of the panel). The sketches in figure 44 and 

figure 45 show details of the test setup and transducer location for both tests.

6-inch by 6-inch plate 20-inch by 10-inch plate

Figure 44. Diagrams. Tested load footprints.
73

6-inch by 6-inch footprint test setup 20-inch by 10-inch footprint test setup

Figure 45. Diagrams. Test setup used to evaluate footprint effect.

Steel plates were used to create the two different footprints. The photographs of different details 

of the test setup are shown in figure 46.

20-inch by 10-inch footprint- side view 20-inch by 10-inch footprint – LVDT location
74

6-inch by 6-inch footprint-test set-up 6-inch by 6-inch footprint-LVDT location

Figure 46. Photos. Test setup details.

During both tests (the same panel was used, first loaded with larger footprint, unloaded, then 

smaller footprint and unloaded), cracking sounds were heard during the loading phase, but no 

visible damage or cracks were observed after unloading and removal of the steel plates. The plots 

in figure 47 show the load-deflection response as captured by the actuator, spring pot (bottom of 

the panel), and LVDT (top of panel). Results are summarized as follows: 

• 6-inch by 6-inch footprint test: Max load is 25.1 kips. Max displacement: 0.146 inch 

registered by actuator; 0.080 inch by LVDT; 0.092 inch by the string pot.

• 20-inch by 10-inch footprint test: Max load is 25.12 kips. Max displacement: 0.109 inch 

registered by actuator; 0.074 inch by the LVDT; 0.068 inch by the string pot. 

6-inch by 6-inch footprint test 20-inch by 10-inch footprint test

Figure 47. Graphs. Load-deflection responses of the two footprint tests.
75
76

APPENDIX H: PANEL FATIGUE TEST REPORT

DESCRIPTION OF THE TESTED SPECIMEN

This appendix reports the details of testing a panel composed of seven FRP tubes with no grout. 

Manufacturing details are listed in figure 48. The panel was positioned WSD, as shown in figure 

49. The length of panel is 11 feet; the cross section dimensions are shown in figure 50.

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.
77

DESCRIPTION OF TEST SETUP

Figure 51 shows the fatigue test setup. The FRP panel was tested under three-point loading 

(hydraulic actuator at midspan). Half-round steel sections were used as support between a 5.5-

foot span. A 110-kip load cell was used to collect the load data. To prevent possible “pounding” 

effects between the FRP deck panel and the supports during testing, two clamps were used at 

each side. Two steel plates (12 inches by 12 inches by 1.25 inches) were used under the 

hydraulic actuator to create a 144 in2 distributed load over the FRP specimen. One LVDT was 

placed at the midpoint of bottom face of the panel to measure the deflection during the static load 

tests; it was used to measure flexure stiffness.

Figure 51. Photos and diagram. Fatigue test setup.
78

TEST PROGRAM

Load was applied on a range of 1 to 14 kips in flexure (compression on top face of panel) using a 

hydraulic actuator. A command sinusoidal wave with a 1.5 Hz frequency was used. Testing 

started at 7:00 am every day and ended at 10:00 pm. This cyclic testing was interrupted one time 

during the day (at 1:00 pm) to conduct a monotonic test (under displacement control). The 

specimen was loaded up to 14 kips and unloaded; 14 kips is considered equivalent to the effect 

of the design truck (16 kips) times the dynamic allowance (1.15) times the load factor assuming 

a finite life check (0.75). Load, displacement (from LVDT and actuator), and strains at various 

locations were recorded. Cyclic testing resumed after that. From each monotonic test, flexure 

stiffness as a function of the number of cycles was calculated (load range of 2 to 12 kips). Table 

28 provides this information, as well as the ratio of each stiffness value with respect to that at 

zero cycles. Figure 52 shows the stiffness ratios as a function of the fatigue load cycles. 

Table 28. Flexure stiffness as function of increasing number of fatigue cycles.

Date Time Cycle 

done

LVDT Actuator

Stiffness, kip/in

(from 2 kip to 12 kip)

Stiffness/initial 

stiffness

Stiffness, kip/in

(from 2 kip to 12 kip)

Stiffness/initial 

stiffness

06/18/2012 10:00am. 0 69.11 1.000 51.16 1.000

06/18/2012 3:30pm. 14722 70.44 1.019 53.19 1.040

06/20/2012 1:00pm. 149542 70.49 1.020 53.84 1.052

06/22/2012 1:00pm. 290100 69.59 1.007 53.78 1.051

06/24/2012 1:00pm. 436342 70.02 1.013 53.73 1.050

06/25/2012 1:00pm. 507044 68.84 0.996 53.30 1.042

07/03/2012 1:30pm. 655021 68.36 0.989 53.44 1.045

07/05/2012 1:00pm. 793782 69.01 0.999 55.13 1.078

07/08/2012 1:00pm. 980990 69.07 0.999 55.80 1.091

07/08/2012 9:50pm. 1025326 69.78 1.010 55.46 1.084

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).

The graph at the left of figure 52 shows that the stiffness ratios measured at different cycles did 

not vary more than 3 percent from the original stiffness. It can be concluded that after 1 million 
79

cycles there is no evidence of stiffness degradation. At 500,000 cycles, the test was temporarily 

stopped so a wearing surface could be applied to the bottom face of the FRP panel deck; see 

figure 53. After the cyclic testing resumed, a drop on the stiffness ratio was experienced for 

about 130,000 cycles, as shown in the graph at the right of figure 52. The maximum value 

corresponded to a 6 percent drop at 570,000 cycles; however, it vanished after that (650,000 

cycles). It is hypothesized that because the wearing surface was applied quite close to the support 

area (see the photograph in figure 53), it might have produced a gap between the support and the 

panel, which caused the stiffness to temporarily drop. 

Wearing surface on bottom side 

(which is subjected to tension) after 1 

million cycles fatigue load

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 shows the load-deflection behavior at different fatigue cycles. The load-deflection 

curve is not quite linear; see for comparison the tangential line drawn in figure 54. The panel 

becomes “stiffer” after the load reaches 6 kips. The initial load-deflection curve matches well 

with the curve after 1 million cycles of fatigue loading. The slope of the load-deflection curve at 

570,000 fatigue cycles is slightly smaller than the slope of the initial curve, which is indicated as 

a stiffness drop in figure 52.
80

Figure 54. Graph. Load-deflection behavior at different fatigue cycles.

To evaluate the sensitivity of the stiffness measurements to the time of the day when they are 

taken, the flexure stiffness was measured three times a day from June 22 to June 24, 2012 (at 

7:00 am, 1:00 pm, and 10:00 pm.) Results are shown in figure 55. Although these results show 

that the stiffness measurements change within the day (changes in the order of 2 percent were 

found), no clear pattern was determined, although it appears that there is a drop of stiffness 

overnight.

Figure 55. Graph. Stiffness change during daytime.

As indicated before, a wearing surface composed of epoxy compound and exposed aggregate 

was applied at the bottom of the FRP panel (subjected to tension) at 500,000 fatigue cycles. In 

addition, the same type of wearing surface was installed at the top of the panel (subjected to 

compression) at 650,000 fatigue cycles. Both were applied over an area of 29 inches by 24 

inches. After 1 million cycles fatigue load, neither the top nor the bottom wearing surfaces

showed any visible damage or cracks. Figures 56 and 57 show photographs of the wearing 

surfaces before and after their respective exposure to cyclic loading.

Figure 58 shows the position of five strain gages (SG1-SG5) installed on the FRP panel surface. 

SG1 and SG2 were placed on the top face beside the loading steel plate. SG3 (top) and SG4 
81

(bottom) were placed at midspan toward the edge of the panel. SG5 was installed at the midpoint 

of the bottom face of the panel.

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.

BottomBottom-FinalTopTop-Final
82

Figures 59 through 62 show load-strain behavior for the five strain gages at different fatigue 

cycles. Despite the presence of small residual strains, load-strain curves for SG1 and SG4 

showed little change during the fatigue test (see figures 59 and 60). In figure 61, the slope of the 

curve for SG3 at 1,000,000 fatigue cycles is almost the same as the initial one. However, the 

slope at 500,000 fatigue cycles is 21 percent smaller. Figure 62 shows that the slope of the curve 

for SG5 at 500,000 fatigue cycles is smaller (15 percent) than the initial slope and remains 

similar at 1,000,000 fatigue cycles. Load-strain behavior of SG2 in figure 63 shows a large 

residual strain at this location. At 500,000 fatigue cycles, there is a sudden change of slope at 6.5 

kips; this may due to the local damage of the FRP deck (or strain gage) at this location.

Unfortunately, SG2 was broken due to the slight movement of the loading steel plate at around 

600,000 fatigue cycles, so no more data were collected beyond that point.

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).
83

CONCLUSIONS

Based on the experimental program developed, the following conclusions can be drawn:

• The fatigue test shows that there is no stiffness degradation of the FRP panel after 1 

million cycles fatigue load (1 to 14 kips of midspan loading).

• Load-deflection plots show a slightly nonlinear behavior of the FRP panel. The panel 

becomes “stiffer” after the load reaches 6 kips. 

• The wearing surface subjected to tension stresses shows no visible damage or cracking

after 500,000 cycles fatigue load; the wearing surface subjected to compression shows no 

visible damage or cracks after 350,000 cycles fatigue load.

• Load-strain behavior of SG2, located on the top surface near the applied loading plate,

indicates the possibility of localized damage of the FRP deck (or strain gage) area at that 

location at 360,000 fatigue cycles.
84

APPENDIX I: PANEL-TO-PANEL FIELD JOINT REPORT

DESCRIPTION OF TESTED SPECIMEN

The test specimen for a panel-to-panel field connection was made by joining the edges of two 

small panels together (FRP tubes and outer wrap) and filling the gap between them with an 

epoxy grout compound and aggregate, as shown in figure 64. The width of the specimen is 18 

inches. The cross section dimensions are shown in figure 65.

Figure 64. Photo. Panel-to-panel field joint.

Figure 65. Diagram. Cross section dimensions.

DESCRIPTION OF TEST SETUP

Figure 66 shows the test setup. The FRP panels were loaded using an 18-inch-long steel roller (2 

inches in diameter). Two steel I beams (4 inches by 6 inches by 0.2 inches) were used for support 

between an 8-inch span length (centerline to centerline). Due to the gap created by the wearing 

surface between the FRP panel and supports, neoprene pads were used on top of the steel 

supports to more evenly distribute the loading. A 220-kip load cell was used to collect load data. 

One string pot was placed at the midpoint of bottom face of the specimen (grout key) to measure 

the vertical displacement. Two LVDTs were placed on the top face of the panel at the centerline 

of each steel support and 3 inches away from the panel side to measure the deformation of the 

FRP specimen at the supports; it will be assumed that any deformation at this location will come 

primarily from the neoprene pads deformation underneath. One strain gage (SG) was installed at 

the side of the epoxy “key” near the bottom face to measure possible tension strains generated at 
85

this location. The specific locations of the string pot, LVDTs, and strain gage are shown in figure 

66.

Figure 66. Photos and diagrams. End panel connection test setup.

TEST PROGRAM

The panel was loaded under displacement control. A small cracking sound was heard at 5 kips. A 

visible crack at the interface between the epoxy key and one of the end panels was observed at a

load of 7 kips, as shown in figure 64. A sudden drop of load occurred at 14.7 kips, and the load 

dropped to 10.7 kips. A large opening of the interfacial crack was observed at this point. The test 

continued under increasing displacement, and a very small load increase was registered. The 

crack opening became wider. At a string pot deflection of 0.275 inches and a corresponding load 

of 11.8 kips, the bond between the epoxy key and the end panel failed, and the specimen 

separated into two parts, as shown in figure 69.

Figure 70 shows the load-deflection data from the string pot and two LVDTs. The net specimen 

displacement was taken as the net value between the displacement measured by the string pot 

and the mean value measured by the two LVDTs. The resulting plot is shown in figure 71. At the 

maximum load of 14.7 kips, the net displacement of the specimen is 0.06 inches. The net 

displacement is 0.11 inches at the failure load of 11.8 kips. The negative displacement values in 

figure 71 may be due to the uneven distribution of reaction forces on the neoprene pads at very 

small applied loads. It is possible that this caused one of the LVDTs to deform more than the 
86

other one and the string pot at the same load level (up to 5 kips of applied load), as shown in 

figure 70.

Figure 72 shows the load-strain behavior of the epoxy key. It shows an overall linear behavior. 

The maximum tensile strain at failure load is 534 με.

Figure 67. Photo. Crack at load of 7 kips.

Figure 68. Photo. Crack at maximum load of 14.7 kips.
87

Figure 69. Photo. Failure of the specimen (11.8 kips).

Figure 70. Graph. Load-deflection behavior.

Figure 71. Graph. Net specimen displacement.
88

Figure 72. Graph. Load-strain behavior of the epoxy key.

Figure 73 shows the two surfaces of the failed specimen. It should be pointed out that a layer of 

wearing surface was applied on the surface of the end panel prior to filling out the gap with 

epoxy compound to form the epoxy key. After failure, it was observed that the aggregates of the 

wearing surface were almost totally detached from the end panel surface and were primarily 

attached to the epoxy key side. The end panel failed surface shows a layer of the epoxy from the 

wearing surface and a small remaining portion of the aggregates. The crack line is shown as a 

dotted line in Figure 11.

Figure 73.. Photos The two failed surfaces.

Figure 74. Diagram. Sketch of the crack line.

Crac

k 
89

CONCLUSION

The FRP end panel connection specimen was built joining two smaller end panels (FRP tubes 

and outer wrap) and filling their gap with an epoxy compound and aggregate. The specimen 

failed by a crack propagating at the interface between the epoxy key and one of the end panel 

surfaces. It can be characterized as a bond failure between the wearing surface and the end panel. 

The maximum obtained load was 14.7 kips; the maximum tensile strain registered on the epoxy 

key was 534 με. The failed surfaces showed that the aggregates of the wearing surface were 

almost totally detached from the end panel surface and were primarily attached to the epoxy key 

side.
90

APPENDIX J: BRIDGE RAILING POST ANCHORAGE PROOF TEST

DESCRIPTION OF THE TEST SPECIMEN

An empty FRP panel, used previously to determine flexure stiffness (panel #3), was selected to 

fabricate the railing post-FRP deck connection. The FRP panel consisted of seven FRP tubes 

with the narrow side of the panel facing the rail. A steel railing post was mounted over a highdensity polyethylene (HDPE) pad and attached to the FRP deck using four 1-inch threaded 

anchors, connecting the railing post to a steel base plate on the bottom face of the FRP deck. 

Figure 75 shows details of the different components of the railing post specimen. The steel base 

plate had four bolts welded onto the plate; the anchor rods were bolted to the rail base until they 

felt “snug-tight.”

Figure 75. Photos and sketch. Railing post specimen.

DESCRIPTION OF TEST SETUP

Figure 76 shows details of the specimen test setup. Two steel beams (W6x20) were used to 

attach the FRP panel to a structural frame; their distance to the railing post base as well as to 

each other was based on the full-scale prototype. A hydraulic ram (22-ton capacity and 6-inch

stroke) was used to apply force on the railing post at 25 inches from the base of the deck panel. 

The FRP deck was connected to the steel beams using hollo-bolts, flat-clips, and washers (see 

figure 77) similar to those that will be used in the full-scale prototype. The hollo-bolts were tight 

using the “turn-of-the-nut” procedure: the nuts were turned 1/3 after snug-tight conditions. After 

the bolts were tensioned, the torque in each bolt torque was verified using a calibrated torque 

wrench, and it was found to be in the order of 65 to 75 lb-ft. 
91

(a) Side View (b) Top View

(c) Photograph of Test Set-up (d) Front View

Figure 76. Photo and diagrams. Railing post test setup.

To secure the W6x20 girders to the structural frame, steel braces, A490 bolts, and dywidag bars 

were used. Neither the FRP panel nor the braces were directly attached to the floor.
92

(a) Photograph showing bracing system (b) Bracing system & hollo bolt details

Figure 77. Photo and diagram. Detailing of steel beam-structural frame connection.

To measure deflections, six dial gages and four string pots were attached to the FRP deck, railing 

post and W6x20 girders. In addition, digital image correlation was used to monitor the 

movements of few of the bolts on the back side of the panel. Figure 78 shows photographs and 

location of all these transducers; their orientation with respect to a Cartesian axis of reference is 

also indicated in these images.

Structural 

Frame

Steel 

Brace

W6x20

Dywidag 

Bar

A490

Bolts
93

(a) Profile view of gage locations (b) View of hydraulic ram at 32 kip-failure

(e) Top View of railing post gages

Figure 78. Photos and diagrams. Location of transducers used during the test.

Y

Z X

Y

Z

Z

X

(f) Top view of post & L-brackets - Test 1

(c) Back view of gage locations (d) Photograph of panel back view
94

TEST PROGRAM

Test Procedure

The first test (Test 1) was completed on July 16, 2012. A 7-inch-diameter steel plate was placed 

on top of the hydraulic jack to distribute the load; see figure 78f. The specimen was 

incrementally loaded, and measurements were taken at 0, 3, 6, 9, 12, 13.5, and 15 tons. At 15-ton 

(30-kip) load, the steel plate sat at a very pronounced angle, so the test was stopped to prevent 

instability in case of failure. Measurements were not taken during the unloading part.

With a roller support on the ram to increase stability (figure 78b), Test 2 was completed on July 

17, 2012. For this test, it was decided to load the specimen to AASHTO TL-2 load level (27 

kips), unload incrementally to obtain more complete data, then load the specimen again up to 

failure (Test 2-Failure) and back down. Table 29 shows the data points recorded for the end rail 

displacement measured by string pot 2 (see figure 78a) for all tests; figure 79 shows a plot of 

these data. For Test 2, due to the possibility of large deformations and brittle failures, some 

transducers were removed (string pots 1 and 3 and the digital image correlation camera); in 

addition, Dial_X3 and Dial_Y3 replaced two LVDTs to record the data at the same locations.

Table 29. Load-displacement data for string pot 2.

Deflection (in.)

Load (kip) Test 1, 

Max 30 kip

Test 2, 

Max 27 kip

Test 2-Failure, 

Max 32 kip

0 0.000 0.000 0.214

6 0.904 1.171 1.323

12 1.406 1.739 1.916

18 1.941 2.356 2.457

24 2.447 - 2.980

27 2.758 3.114 3.219

30 3.336 - 3.611

32 - - 4.383

32 - - 5.208

20 - 2.960 4.850

12 - - 4.220

10 - 2.205 -

6.4 - 1.815 -

6 - - 3.520

0 0.419 0.214 1.048
95

Figure 79. Graph. Load-displacement behavior of railing post end (string pot 2).

Failure Modes

No cracking sound was heard during Test 1 or Test 2 up to 27 kips. When the specimen was 

reloaded again (Test 2-Failure), cracking sounds were heard around 32 kips. It was also observed 

that, under increasing displacement, no further load increase was obtained. At a displacement of 

5.2 inches, registered by string pot 2 (see figure 78b), the railing post-FRP deck connection 

failed when a corner of the back steel plate was pulled (wedged) into the FRP deck, as shown in 

figure 80a. As noted, the significant deformation of the rail base and HDPE pad is believed to be 

the reason for the increasing pulling forces on the bolts at the bottom of the steel base plate. The 

steel plate was bent as a result of this pulling effect; figure 80b shows the extent of the 

deformation. The wedging effect caused a local shear failure of the deck through the first layer of 

the tubes (aka punching shear), shown in detail in figures 80c and 80d. Post-test visual 

observations of all bolt holes in the FRP panel both at the railing post and hollo-bolt connections 

revealed no signs of bearing failure. Figure 79 shows that non-linear deformation (most likely 

coming from the failure of the connection) started between 30 and 32 kips. Permanent 

deformation registered by string pot 2 was in the order of 1 inch. 

0

5

10

15

20

25

30

35

0.0 2.0 4.0 6.0

Force, kip

Displacement, in

Test 1

Test 2

Failure
96

Figure 80. Photos. Failure mode of the railing post-FRP deck panel connection.

Vertical Displacement of the Railing Post

In Test 1, three string pots were attached to the railing post to measure its total vertical 

displacement relative to the ground. String pots 1 and 3 were used to monitor any possible 

rotation of the railing post during loading, whereas string pot 2 was placed at the railing post end;

see figure 81. Results indicate that the railing post was loaded symmetrically across its width. 

(a) Steel plate wedging failure (b) Bent on steel plate

(c) FRP deck panel failure-close-up (d) FRP deck failure-photograph post-test
97

(a) Railing post load-displacement behavior (b) Photograph of 3 string pots used

Figure 81. Graph and photo. Vertical displacement of the railing post, Test 1.

The large amount of vertical displacement registered by the string pots indicates that, in addition 

to the railing post deformation, other sources of deformation also contributed to this 

displacement: 1) the rotation and movement of the anchor bolts connecting the post to the FRP 

deck panel, which in turn allowed for railing post base and HDPE rotation, 2) the HDPE pad

deformation, 3) the FRP deck panel deformation, 4) the possible movement of the hollo bolt 

connections, and 5) movement of the bracing system used to secure the steel beams to the 

structural frame. Figure 82 shows a sketch illustrating these possible sources of deformation. In 

the next sections, they will be described in more detail.

Figure 82. Diagram. Railing post connection (deformed shape, not to scale).

0

5

10

15

20

25

30

35

0.0 1.0 2.0 3.0 4.0

Force, kip

Displacement, in

(1) String Pot 1

(2) String Pot 2 

(3) String Pot 3

(1)

(3)

(2)
98

Contributors to the Railing Post Vertical Displacement

The total vertical displacement at the end of the railing post at 27 kips (AASHTO TL-2), and 

failure (32 kips) was 3.11 inches and 5.21 inches, respectively. The deformation of the HDPE 

pad was found to be a significant contributor of this vertical displacement. (For reference, the 

AASHTO Load and Resistance Factor Design Bridge Design Specification for TL-3 and TL-4 

uses 54 kips; rail heights are also higher.)

HDPE Deformation

The four corners of the HDPE pad closest to the railing post base were measured against the FRP 

deck face using calipers. Table 30 shows values of the change in distance from the original 

position at zero-load for Test 2. Corners A and B are located toward the edge of the FRP deck 

panel, whereas corners C and D are on the opposite side, see figure 83.

The measurements show that the HDPE pad at corners A and B was compressed under 

increasing load, whereas corners C and D were stretched. A straight bar was used during testing

to confirm that the HDPE pad was bending under increasing load; therefore, it cannot be 

assumed that it deforms as a rigid plate. After failure of the steel plate and unloading of the 

specimen, permanent deformation of the HDPE was also measured at the corners. 

To estimate the contribution of the HDPE deformation to the vertical railing post displacement, 

its rotation was calculated based on the deformations recorded in table 30. At 27 kips of applied 

load, it was estimated that the vertical deflection at the end of the railing post corresponding to 

the HDPE rotation was in the order of 40 percent of the total value measured by string pot 2. It is 

also expected that the HDPE deformation would have greatly increased the tension forces in the 

bottom two bolts of the railing post connection. The gap between the railing post base and the 

HDPE pad was measured in the vicinity of the maximum load of 32 kips and found to be in the 

order of 0.125 inches.

Table 30. Test 2 HDPE pad deformation.

Horizontal Displacement from FRP deck surface (in.)

Load (kip) Corner A Corner B Corner C Corner D

0 0.000 0.000 0.000 0.000

12 0.039 0.038 -0.221 -0.171

18 0.047 0.033 -0.269 -0.211

27 0.055 0.055 -0.352 -0.313

30 0.063 0.056 -0.425 -0.386

0 -0.020 0.004 -0.146 -0.094
99

(a) Sketch showing HDPE pad corners (b) HDPE deformation at 27 kip

(c) HDPE deformation at max load (32 kip) (d) HDPE deformation post steel plate failure

Figure 83. Photos. HDPE deformation at different loading levels, Test 2.

FRP Deck Deformation

Movement of the FRP deck panel in two directions was recorded using LVDTs and dial gages. 

Displacement in the direction perpendicular to the applied load (x-direction) was estimated from 

dial gages Dial_X1, Dial_X2, and Dial_X3. Dial_X2 and Dial_X1 measure the FRP deck 

movement with respect to the top and bottom steel girder, whereas Dial_X3 measures the total 

movement of the top of the panel relative to the structural frame (attached to the floor). Figure 84

shows these deformations for Test 2. As expected, the deformation of the FRP deck panel is 

larger toward the cantilever edge and smaller near the steel girder support. At the location near 

the second (bottom) steel girder, the FRP panel experiences a reversed curvature, thus deforms in 

the opposite direction than the cantilever edge. The curves on figure 84 show that the FRP 

deforms linearly up to 30 kips; beyond that load level, non-linear deformations appear, possibly 

associated with the damage of the railing post connection. At 27 kips, the displacements 

registered by Dial_X3, Dial_X2 and Dial_X1 are 0.195, 0.188, and -0.233 inches, respectively. 

C

A

C

B

A

A C
100

Figure 84. Graph. Horizontal deflection (x-direction), Test 2.

Figure 85 shows the vertical displacements (in the y-direction) recorded by the three dial gages 

during Test 2. Dial_Y1 and Dial_Y2 measure the vertical movement of the FRP panel relative to 

the adjacent steel girders while Dial_Y3 measures the overall movement of the top of the FRP 

panel (with respect to the structural frame, attached to the floor). As expected, the displacement 

of the top of the FRP panel is larger than those near the steel girders. The behavior of Dial_Y3 

shows that the panel does not return to its initial position after the first unloading. After failure of 

the railing post connection, the specimen was unloaded; the permanent displacement of the FRP 

deck at the top was found to be 0.058 inches.

Figure 85. Graph. Vertical displacement (y-direction), Test 2.

0

5

10

15

20

25

30

35

-0.4 -0.2 0.0 0.2 0.4 0.6 Force, kip

Displacement, in

(1) Dial_X1

(2) Dial_X2

(3) Dial_X3

(1)

(3) (2)

0

10

20

30

40

-0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30 Force, kip

Displacement, in

(1) Dial_Y3

(2) Dial_Y2

(3) Dial_Y1

(1) (3) (2)
101

The vertical displacement at the top of the FRP panel (Dial_Y3) is a combination of the relative 

movement of the steel girders with respect to the structural frame, as well as the true 

“elongation” of the panel under loading. To evaluate the magnitude of the FRP elongation, the 

deflection of the bottom girder relative to the floor was measured by string pot 4 (see figure 86).

At 27 kip of loading, string pot 4 registered 0.082 inches. This small deflection suggests that the 

brace and bolt system used to hold the steel girders and FRP deck panel system in place, 

performed well. Overall, this global movement was limited to about 3 percent of the total 

movement railing post end displacement. 

At 27 kip of loading, the top of the FRP deck panel displaced 0.195 inches (captured by 

Dial_Y3). Assuming that the first steel girder deformed in similar magnitude as the second girder 

(measured by string pot 4), it can be assumed that the FRP elongated 0.113 inches at this loading 

(4 percent of the vertical deflection measured by string pot 2, discussed previously). 

Figure 86. Graph. String pot 4 movement, Test 2.

Bolt Movement

The digital image correlation technique was used to monitor the movement of three bolts in the 

back of the FRP deck panel during Test 1 (loading up to 30 kips and unloading): two bolts on the 

steel base plate and one on the steel fastening clip. To protect the digital equipment, digital 

image correlation was not used during Test 2 to failure. Figure 87 shows the location of the 

monitored bolts as well as their movements, with increasing loading with respect to the Cartesian 

coordinate system used in this report (y, z axis). 

Bolts 1 and 2 were expected to have similar movements with respect to each other since they 

were both attached to the steel base plate. They both show similar displacements (0.17 inches

upward) in the y axis, but their displacements in the z axis are in the opposite directions. Bolt 3 

(expansion bolt connecting the FRP panel to the first steel girder) showed smaller displacement 

values in the y direction (0.10 inch), but similar in magnitude to the global displacement 

measured by string pot 4. 

0

10

20

30

40

0.000 0.025 0.050 0.075 0.100 0.125 0.150

Force, kip

Displacement, in

String Pot 4
102

(a) Photograph of the back of the FRP deck; area used for digital image correlation is 

highlighted

(b) Bolt 1 displacement (c) Bolt locations

(d) Bolt 2 displacement (e) Bolt 3 displacement

Figure 87. Photos and graphs. Movement of three bolts on FRP back panel using digital image 

correlation, Test 1.

0

0.05

0.1

0.15

0.2

-0.2 -0.15 -0.1 -0.05 0

Y-direction displacement, in

Z-direction displacement, in

0

0.05

0.1

0.15

0.2

-0.05 0 0.05 0.1

Y-direction displacement, in

Z-direction displacement, in

0

0.03

0.06

0.09

0.12

0 0.02 0.04 0.06

Y-direction displacement, in

Z-direction displacement, in

(3) (2)

(1)

Z

Y
103

Expansion Bolt Connection

As indicated before, the FRP deck was connected to the steel beams using 5/8-inch-diameter 

expansion (hollo) ebolts, flat-clips, and 3/8-inch-diameter washers (see figure 88a). The 

expansion bolts were tightened using the “turn-of-the-nut” procedure. The bolt length (3 inches) 

allowed them to pass through two walls of the FRP tubes, as shown in figure 88b. During the 

testing of the railing post, the movement of one of the bolts was monitored using digital image 

correlation, showing very small displacement values that can be related to the movement of the 

steel girders. After the test was concluded, visual inspection of all the bolt holes in the FRP panel 

revealed no signs of bearing failure. It can be inferred that the bolted connection was able to 

effectively hold the FRP panel in place, up to the load and displacement levels when the railing 

post connection failed.

(a) Sketch of bolt connection (b) Cross section of FRP tube & 

connection

(c) Profile view of bolted connection (d) Typical FRP deck hole (post test)

Figure 88. Diagram and photos. Expansion bolt connection.
104

CONCLUSIONS

• The railing post connection, as tested, meets the AASHTO TL-2 required capacity of 27 

kips. 

• Under the applied loads, the vertical railing post end displacement was in the range of 3 

inches at 27 kips and over 5 inches once loaded to a failure load of 32 kips. This 

displacement is attributable to many contributing factors.

• Deformations of the HDPE pad were found to significantly contribute to the displacement 

of the railing post during test. 

• At loads between 30 and 32 kips, the corners of the steel base plate were wedged through 

the first layer of the FRP tube; this was defined as the “failure” stage of the test.

• Based on post-testing observations, none of the bolt holes in the FRP deck panel 

exhibited bearing failures.

• The bracing system used was effective in limiting the FRP panel/steel girder movement 

to about 0.1 inches upward.
105
106

APPENDIX K: WEARING SURFACE TEST

DESCRIPTION OF THE TEST SPECIMEN

A section of an FRP panel, similar to the specimen used for the end panel connection test (see 

Appendix I), and with a wearing surface composed of adhesively bonded flint aggregate, was 

tested following ASTM D 7522 guidelines. The stone was identified as R65-8. The gradation 

was such that 65 percent is retained on a #8 sieve and 20 to 30 percent is retained on a #6 sieve. 

Test results provide the pull-off strength of the adhesive bonded to the FRP surface, as well as 

the pull-off strength of the aggregate embedded into the adhesive. Figure 89 shows photographs 

of the specimen and the wearing surface.

Figure 89. Photos. FRP specimen used for pull-off tests.

DESCRIPTION OF TEST SETUP

Two test areas were prepared for the two different interfaces (see figure 90). To test the 

adhesive-FRP pull-off strength, the layer of aggregate was removed with a hand grinder. Special 

attention was given not to remove the adhesive layer. The area was cleaned, and dollies 1, 2, 3, 7, 

8, and 9 were bonded with a two-part epoxy. After 24 hours of curing, the areas around the 

dollies were scored through the layer of adhesive and into the FRP. To test the pull-off strength 

of the aggregate to the adhesive, the second test area was cleaned and loose aggregate removed.

Zones with an even amount of aggregate were chosen (to minimize bonding of the epoxy and the 

adhesive). Dollies 4, 5, and 6 were not scored because it was feared the drill would rip the 

aggregate out as opposed to grinding it. 
107

(a) Adhesive-FRP test (b) Aggregate-adhesive test

Figure 90. Photos. Dollies mounted to two test areas.

TEST PROGRAM

Using a pull-off adhesion tester, all the dollies were removed. Due to incorrect calibration, data 

from dollies 1, 2, and 3 were rendered invalid. Results from testing the remaining dollies are

presented in table 31.

Table 31. Pull-off test results.

Specimen

Recorded 

Stress (psi)

Area Corrected 

Stress (psi)

Adhesive 

to 

Aggregate

4 621 292

5 886 380

6 767 372

Adhesive 

to FRP

7 850 850

8 900 900

9 726 726

Figure 91 shows the failure surface for dollies 4, 5, and 6. Since failure did not occur along the 

dolly perimeter, as the apparatus assumed, the stress was calculated over the area within the 

aggregate perimeter. The average “area corrected” stress, reported in table 31, was only 348 psi,

which reflects how easily individual pieces could be removed by hand on the original specimen 

prior to testing.
108

Figure 91. Photos. Failure surfaces of aggregate to adhesive pull-off tests (dollies 4, 5, and 6).

Dollies 7, 8, and 9, shown in figure 92, had higher pull-off strength, with an average of 825 psi. 

The failure occurred along the adhesive-epoxy interface, so no area correction was required. 

Some small pieces of aggregate that were too close to the FRP layer to be removed when 

grinding was done, appeared in the failure surface, thus indicating that the bond strength between 

the aggregate and the adhesive will always be the weakest layer and that the bond strength 

between the adhesive and the FRP surface is stronger than 825 psi.

Figure 92. Photos. Failure surfaces of adhesive to FRP pull-off tests (dollies 7, 8, and 9).

7 8

4

9

5 6
109
110

APPENDIX L: FIRE TEST REPORT

DESCRIPTION OF TESTED SPECIMEN

A full-depth panel measuring 3 feet by 7 feet was tested to evaluate its fire resistance properties.

The standard design of the panel uses fire-resistant resin, but no further protection was provided.

It was tested without a wearing surface. See figure 93.

Figure 93. Photo. Test panel mounted on top of fire chamber.

DESCRIPTION OF TEST SETUP

The test specimen was placed over the pilot scale combustion chamber, resting atop and 

perpendicular to two structural steel support beams (I-beams) spaced 24 inches on center (to be 

consistent with the proof-of-concept bridge in Allegany County). The support beams each 

measured 10.5 inches high with 4-inch-wide flanges and 0.25-inch web thickness. The 

surrounding exposed areas were enclosed with 1-inch-thick non-combustible gypsum shaft liner 

panels. Only a portion of the length was exposed to the fire over the combustion chamber.

Figure 94 shows the fire test chamber and the steel beams used to support the deck. This picture 

was taken after the test; note the peeled paint above the fire chamber.

Figure 94. Photo. Support beams spaced at 2 feet.
111

The panel was loaded to a total superimposed load of 1,600 lb, nominally, using a water-filled 

steel tank, shown in figure 95, and instrumented with numerous thermocouples. Figure 96 and 

table 32 detail the placement of the thermocouples. The tank rested on the wood shown at the 

center of figure 93. This wood was dimensioned to reflect the standard AASHTO 10-inch by 20-

inch footprint of a design vehicle. 

Figure 95. Photo. 1,600-lb water tank used as concentrated load.

Figure 96. Photos. Placement of thermocouples on the test panel.

1

2

3 4

5

6

9

8

7
112

Table 32. Details of thermocouple placement.

Thermocouple X, Y Location Z Location

TC01 on longitudinal axis, 42" from transverse axis top surface of deck panel

TC02 on longitudinal axis, 24" from transverse axis top surface of deck panel

TC03 10" from longitudinal axis, on transverse axis top surface of deck panel

TC04 10" from longitudinal axis, on transverse axis top surface of deck panel

TC05 on longitudinal axis, 24" from transverse axis top surface of deck panel

TC06 on longitudinal axis, 42" from transverse axis top surface of deck panel

TC07 on longitudinal axis, on transverse axis 1-3/8" from top surface of 

deck panel

TC08 on longitudinal axis, on transverse axis 3-1/2" from top surface of 

deck panel

TC09 on longitudinal axis, on transverse axis 4-5/8" from top surface of 

deck panel

TEST PROGRAM 

The panel was loaded with the water tank before igniting the chamber and bringing the 

temperature to approximately 1,600 degrees Fahrenheit. The heat was applied for 20 minutes, at 

which time the test was stopped due to excessive smoke. Deflection measurements of the bridge 

deck panel, provided in table 33, were recorded at 1-minute intervals for the entire test duration. 

A technician sighted in on a leveling rod to measure the amount of deflection under load.
113

Table 33. Deflection measurements.

FC-797 K-1084 9/7/2012

Time (min) TC01 TC02 TC03 TC04 TC05 TC06 Grp Avg TC07 TC08 TC09

0.00 76 76 76 76 76 77 76 77 76 78

0.25 77 76 76 76 76 77 76 77 76 78

0.50 76 75 76 76 76 77 76 77 76 78

0.75 76 76 76 76 76 77 76 79 76 77

1.00 76 76 76 76 76 77 76 82 76 78

1.25 76 76 76 75 76 77 76 87 76 78

1.50 76 76 76 76 75 77 76 95 76 77

1.75 76 76 76 76 76 76 76 104 76 78

2.00 76 76 76 76 76 77 76 114 77 78

2.25 76 76 76 76 76 77 76 125 77 78

2.50 76 76 76 76 76 77 76 137 77 78

2.75 76 76 77 76 76 77 76 147 78 77

3.00 76 76 76 76 76 77 76 157 79 78

3.25 76 76 76 76 76 77 76 165 80 78

3.50 76 76 76 76 76 77 76 174 81 78

3.75 76 76 76 76 76 77 76 182 82 78

4.00 76 76 76 76 76 77 76 189 83 78

4.25 76 76 76 76 76 77 76 197 85 78

4.50 76 76 76 76 76 77 76 204 86 78

4.75 76 76 77 76 76 77 76 211 87 78

5.00 76 76 76 76 76 77 76 218 89 78

5.25 76 76 77 76 76 77 76 225 91 78

5.50 76 75 76 76 76 77 76 233 93 78

5.75 76 76 77 76 76 77 76 239 94 78

6.00 76 76 76 76 76 77 76 240 96 78

6.25 76 76 77 75 76 77 76 239 98 78

6.50 76 76 77 77 76 77 76 240 100 78

6.75 76 76 77 77 76 77 76 242 102 78

7.00 76 76 77 77 76 76 76 245 103 78

7.25 76 76 77 77 76 77 77 248 105 78

7.50 77 76 77 77 76 77 77 251 106 78

7.75 77 76 77 77 76 77 77 254 108 77

8.00 77 76 77 77 76 77 77 258 110 78

8.25 77 76 77 77 76 77 77 261 112 79

8.50 77 76 77 77 76 77 77 266 114 79

8.75 77 77 78 77 76 77 77 270 115 79

9.00 77 77 78 77 76 77 77 274 117 79

9.25 77 77 78 77 77 77 77 278 118 79

9.50 77 77 78 77 77 77 77 282 120 79

9.75 77 77 79 77 77 77 77 286 121 79

10.00 78 77 79 78 77 77 77 291 123 79

BRIDGE COMPOSITES LLC
114

Table 33. Deflection measurements, continued.

FC-797 K-1084 9/7/2012

Time (min) TC01 TC02 TC03 TC04 TC05 TC06 Grp Avg TC07 TC08 TC09

10.25 78 77 79 78 77 77 78 295 125 79

10.50 77 77 79 78 77 77 77 299 126 79

10.75 78 77 79 78 77 77 78 303 128 79

11.00 78 77 79 78 77 77 78 307 131 79

11.25 78 77 80 76 77 77 78 311 132 80

11.50 78 78 80 77 77 77 78 316 133 80

11.75 78 78 80 79 76 77 78 320 136 80

12.00 79 78 80 79 77 77 78 325 138 80

12.25 79 77 80 79 77 77 78 331 139 80

12.50 79 78 81 80 78 77 79 337 140 80

12.75 79 78 81 80 78 77 79 342 140 80

13.00 80 78 81 80 78 77 79 348 144 80

13.25 80 78 81 80 78 77 79 354 146 81

13.50 80 78 81 80 78 77 79 360 148 81

13.75 80 78 81 80 78 77 79 365 150 81

14.00 80 79 82 81 78 77 79 369 152 81

14.25 81 79 82 81 78 77 80 374 154 81

14.50 81 79 82 81 78 77 80 379 156 82

14.75 81 79 82 81 78 77 80 384 158 82

15.00 81 79 82 81 79 77 80 389 159 82

15.25 81 79 83 81 79 77 80 395 161 82

15.50 81 79 83 82 79 77 80 401 164 83

15.75 82 79 83 82 79 77 80 407 167 83

16.00 82 79 83 82 79 77 80 413 168 83

16.25 82 80 83 82 79 77 81 420 171 83

16.50 82 80 84 81 80 77 81 427 172 84

16.75 83 80 84 83 79 77 81 432 174 84

17.00 83 80 84 83 80 77 81 438 177 84

17.25 83 81 84 83 80 77 81 443 179 84

17.50 83 81 85 84 80 77 82 448 180 85

17.75 84 81 85 84 80 77 82 453 181 85

18.00 84 81 85 84 80 77 82 458 185 85

18.25 84 82 85 85 81 77 82 463 187 85

18.50 84 82 85 85 81 77 82 467 189 86

18.75 85 82 86 85 81 77 83 473 191 86

19.00 85 82 86 85 81 77 83 477 194 87

19.25 85 83 86 86 81 77 83 481 196 87

19.50 85 83 86 86 81 77 83 484 197 88

19.75 86 83 86 86 81 78 83 488 200 88

20.00 86 83 87 87 82 78 84 493 203 89

BRIDGE COMPOSITES LLC
115

At the end of the test, the panel was still carrying load and generally structurally sound, although 

the resin on the bottom had burned off, exposing glass fiber. The following photos illustrate the 

condition of the specimen afterwards.

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.
116

Figure 100. Photo. The glass fiber on the bottom has frayed due to burn-off of the resin matrix.

RESULTS

The deck panel survived 1,600-degree Fahrenheit temperatures relatively well. The top surface 

did not rise much higher than room temperature (~80 degrees Fahrenheit). Although the bottom 

surface suffered extensive damage, the multi-celled structure protected the upper part and 

reduced the spread of flame and high temperatures. The panel carried the full 1,600 lb. 

superimposed load with a maximum deflection of 5/16 inches. There was no crushing of the 

tubes observed, no excessive bending, and the panel was still functional at the end of the test.
117
118

APPENDIX M: AFTER-TEST REVIEW PRESENTATION
119
120
121
122
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124
125
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