10
Low-temperature and high-temperature load-strain curves were obtained from the strain
gage SG-2 measurements, as shown in Figure 11. The curves for the deck prototype at each
temperature level indicate that there was a significant difference in strain between the FRP
composite decks and the reinforced-concrete deck. However, there was almost no difference in
the loadstrain response between the FRP composite bridge deck fabricated by the pultrusion
process (Bridge #4) and the FRP bridge deck fabricated by the VARTM process (Bridge #3).
The hybrid FRPconcrete bridge deck (Bridge #2) was stiffer (higher load-strain slope) than the
reinforced-concrete deck (Bridge #1), as shown in Figure 11. This difference is attributed to the
greater thickness of the hybrid FRP-concrete deck compared to the reinforced-concrete deck.
Comparisons of deflections and strains corresponding to the maximum load for the five bridge
deck prototypes after 10 million load cycles are presented in Figures 12 and 13. A summary of
deflections and strain values at maximum load is also provided in Table 2.
The significant stiffness change with temperature implies that the deck stiffness was
controlled mainly by temperature changes and not by the number of applied load cycles. The
deck prototypes were inspected visually for signs of distress, such as cracks and damage at
connections after fatigue cycling. No damage was visible in the three FRP composite decks
(Bridge #3, Bridge #4, and Bridge #5), nor any cracks or delaminations were visible in any of the
three polymer concrete wearing surfaces. However, hairline cracks were observed in the tension
region over the FRPconcrete hybrid deck (Bridge #2).
6. CONCLUSIONS
The general conclusions drawn from the results of the investigation are:
1. A protocol for fatigue performance evaluation of FRP composite bridge deck prototypes
under extreme temperatures was implemented.
2. A correlation with a benchmark conventional reinforced concrete deck was established.
3. The load-deflection response (stiffness) of the FRP composite decks was significantly
affected by extreme temperature levels.
4. Progressive degradation in stiffness with load cycling was observed at high temperature,
50C (122F), testing condition for all deck prototypes. At low temperature, 30C (
22F), reduction of stiffness with load cycling was not as significant.
7. ACKNOWLEDGEMENTS
This work was sponsored by the Federal Highway Administration and the Ohio Department of
Transportation through a contract with the University of Cincinnati. The authors thank John
Bouzon, Thomas Tantillo, Jeffrey Stark, Rosanne Stoops, and John Gagnon for the experimental
setup and assistance during testing. Steve Morton, previously with the Ohio DOT, provided test
planning and inspiration for the work.
Previous Page
