Title: Evaluation of Tsunami Force Acting on Bridge Girders

Author(s): Kyuichi Maruyama, Yasushi Tanaka, Kenji Kosa, Akira Hosoda, Taro Arikawa, Norimi Mizutani, and Tomoaki Nakamura

Publication: Symposium Paper

Volume: 313

Issue:

Appears on pages(s): 1-10

Keywords: Tsunami, bridge girder, satellite image, damage analysis, simulation

DOI: 10.14359/51689685

Date: 3/1/2017

Abstract:
This paper deals with what tsunami force acted on bridge girders by Great East Japan Earthquake broken out in March 11, 2011. First of all, a lot of efforts were conducted to collect almost all data of bridge girders in the inundation area. Satellite images in internet websites proved very effective to make a quick survey of any bridge in the inundation area. Detailed data on the bridges were obtained from authorities for use in damage analysis. The method proposed by Prof. Kosa was introduced to see whether bridges were washed away or not by tsunami. The resistance of each bridge is expressed as a function of the self-weight of bridge girder, and the tsunami force is defined by hydro-dynamic equation. More than two hundred bridges, including both washed away bridges and survived ones, were analyzed. Motion pictures taken by digital camera during the attack of tsunami were examined to evaluate the velocity and height of tsunami. As far as bridges in a local area were taken into account, the method was good to see whether bridges were survived or not. Field survey of the bridges washed away indicated that the failures would have been by tsunami uplift force. Experimental investigation was done using a water channel to examine what forces acted on bridge girders and to develop a proper simulation model.