Investigating Wave Forces on Coastal Bridge Decks

• Main Author: Xu, Guoji
• Other Authors: He, Shan
• Format: Others
• Language: en
• Published: LSU 2015
• Subjects: Civil & Environmental Engineering
• Online Access: http://etd.lsu.edu/docs/available/etd-06232015-110945/

Tsunamis and hurricane induced waves are responsible for many coastal bridge failures, especially in the last decade. In the current study, three countermeasures (reducing the entrapped air, elevating the structures and rigidifying the structures) are considered, two wave types (solitary wave theory and Stokes wave theory) are chosen, and two bridge types (single bridge deck and twin bridge decks) are taken into account. Parametric studies are conducted based on Computational Fluid Dynamics (CFD) software ANSYS Fluent. This dissertation comprises two broad themes according to the wave types adopted. The first one is to make a great effort to investigate solitary wave forces on the coastal bridge decks, including suggesting an improved method for predicting solitary wave forces, analyzing the wave forces based on the component level, presenting a quantitative observation for the countermeasure of the air venting holes, assessing the wave forces on the bridge decks with inclinations and with different lateral restraining stiffnesses, and investigating the characteristics of the wave forces on twin bridge decks. The second one is to make exploration of Stokes wave forces on coastal bridge decks, including single bridge deck and twin bridge decks. Based on the obtained results, interesting observations are concluded: (a) an improved method for investigating solitary wave forces on typical bridge decks is suggested and it is proven to make successful predictions; (b) the countermeasure of air venting holes can dramatically reduce the vertical force (based on quasi-static level) when the bridge superstructure is well located around the still water level (SWL); (c) while the wave forces on the landward bridge deck are generally smaller than those on the seaward deck, the interference effects due to the presence of the landward deck on the seaward deck is noticeable for stokes waves in such a way that much larger vertical forces are induced when the gap between the twin bridge decks is around half of the wave length. These observations provide potential suggestions to the future edition of the AASHTO bridge design code.