Xu, G.; Cai, C.S.; Han, Y.; Wu, C., and Xue, F., 2018. Numerical assessment of the wave loads on coastal twin bridge decks under Stokes waves.

In recent hurricane seasons, many coastal low-lying bridges along the Gulf of the Mexico in the United States have suffered huge damages, which has motivated many studies on the failure mechanisms of these coastal infrastructures. While in previous studies one single bridge deck is usually the focal structure type; this study, instead, addresses the features of the wave loads on coastal low-lying bridges with twin decks that are subject to Stokes waves, identifies the wave reflection effects in the twin bridge deck–wave interaction, and brings forward more questions for future studies on this topic. Based on the geometric parameters of the damaged Escambia Bay Bridge, the wave loads on single and twin bridge decks, considering different still water depths with various structure elevations, are compared first. The observed difference in the comparisons of the obtained wave loads shows that the wave reflection plays an important role in the twin bridge deck–wave interaction. Then, the effects of the deck gap between the twin decks of the bridge, the seaward deck and landward deck, are systematically investigated. Both the transverse/horizontal and the vertical wave loads under the prescribed wave conditions are analyzed in detail. The results not only confirm the expectation that the wave loads on the landward bridge deck are usually smaller than those on the seaward one, but also reveal that the wave loads on the twin bridge decks are correlated with the variable deck gap between the twin bridge decks. This study improves the understanding that the wave loads on twin bridge decks, rather than one single bridge deck, under periodical waves need to be quantitatively determined for engineering practices. This study also shows that the wave reflection effects should be appropriately considered on the future revision of the AASHTO code.