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Advances in Civil Engineering
Volume 2011 (2011), Article ID 536171, 12 pages
http://dx.doi.org/10.1155/2011/536171
Research Article

Effect of Ground Motion Directionality on Fragility Characteristics of a Highway Bridge

1Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802, USA
2Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697, USA

Received 1 June 2011; Accepted 27 August 2011

Academic Editor: Manolis Papadrakakis

Copyright © 2011 Swagata Banerjee Basu and Masanobu Shinozuka. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

It is difficult to incorporate multidimensional effect of the ground motion in the design and response analysis of structures. The motion trajectory in the corresponding multi-dimensional space results in time variant principal axes of the motion and defies any meaningful definition of directionality of the motion. However, it is desirable to consider the directionality of the ground motion in assessing the seismic damageability of bridges which are one of the most vulnerable components of highway transportation systems. This paper presents a practice-oriented procedure in which the structure can be designed to ensure the safety under single or a pair of independent orthogonal ground motions traveling horizontally with an arbitrary direction to structural axis. This procedure uses nonlinear time history analysis and accounts for the effect of directionality in the form of fragility curves. The word directionality used here is different from “directivity” used in seismology to mean a specific characteristic of seismic fault movement.