A comparative study on static and dynamic responses of FRP composite and steel suspension bridges

Fiber reinforced polymer (FRP) composites offer many attractive and unique features for existing and new bridges. Among these features are light weight, high stiffness-to-weight and strength-to-weight ratios, damping capabilities, and high resistance to environmental degradation when properly designed and installed. This article presents a pilot numerical study aiming at evaluating the feasibility of using FRP composites in suspension bridge applications. This was accomplished by comparing the response of two identical long-span suspension bridges, one constructed from FRP composite and the other made of steel under static and dynamic loadings using FEM. The numerical results indicated that the responses of the two bridges are different and that the response values obtained for the steel bridge are relatively large compared to the composite bridge. Despite different mode sequences of the two bridge models, the dynamic analysis results indicated that both bridge models have similar mode shapes. As a result of lower self-weight of the FRP composite bridge model, the frequencies of the FRP composite bridge model are larger than those of the steel bridge model.