Experimental Investigation of Tsunami Bore-Induced Forces on Skewed Deck Girder Section Bridges

Abstract

Tsunamis are among the most destructive natural disasters. Recent major tsunamis in Indonesia (2004), Chile (2010), and Japan (2011) resulted in significant loss of human lives and damage to coastal structures. Damages to lifeline infrastructure caused by these disasters have highlighted the need for much more attention from the engineering community to the investigation of tsunami interactions with coastal bridges. Therefore, developing resilient infrastructure that can withstand and remain operational against tsunami bores will significantly improve the postdisaster recovery of the affected areas. In this study, a series of experiments have been conducted in a 15 m long, 1.2 m wide, and 1.2 m deep wave flume equipped with an automatic gate to generate a tsunami bore in order to quantify tsunami-induced loads on a deck girder section bridge. The results of the experiments carried out with a bridge model to investigate the effects of the bridge deck skewness on the tsunami wave-induced forces and moments are presented. The bore height, bore velocity, resulting forces, and moments were measured. It was found that the skewed bridge deck is subjected to additional force and moment components, namely the lateral force ($F_y$ ) and the rolling and yawing moments ($M_x$ and $M_z$ ). These components are nonexistent for the unskewed bridge deck. Based on the experimental results, equations were proposed for estimating the tsunami horizontal, lateral, and uplift forces for a deck girder section bridge.