Stiffness-Driven Design and Interface Debonding Study of FRP Sandwich Structures for Bridges

Bridge decks entirely made of fiber reinforced polymer (FRP) materials are a potential solution to fast construction in bridge engineering. This study mainly focuses on the stiffness-driven design of FRP decks for short-span slab bridges and the interface debonding of an FRP sandwich structure with honeycomb cores. As is evidenced by the analytical and experimental results in this study, these two topics are closely related to the application of FRP materials in bridge deck construction. The design verification of an FRP slab bridge showed that its design should be controlled by stiffness rather than strength. The tests of the FRP sandwich panels at cold temperatures indicated that interface debonding might occur even at the service load level. In order to facilitate the stiffness-driven design of typical FRP slab bridges in practice, this study proposed equivalent strip width expressions which allow them to be designed by Timoshenko beam theory. The key factors for the expressions were identified and a design procedure was recommended in this study as well. Finally, this study investigated the application of tilted sandwich debond (TSD) tests to the interface debonding study of the sandwich structure. This study showed that TSD tests with proper modifications could be used to measure interfacial fracture toughness at different mixed-mode ratios. Recommendations concerning experimental setups and the data reduction method associated with TSD tests were also suggested in this study.

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