%0 Journal Article %T Damage Identification for Prestressed Adjacent Box-Beam Bridges %A Kenneth K. Walsh %A Brendan T. Kelly %A Eric P. Steinberg %J Advances in Civil Engineering %D 2014 %I Hindawi Publishing Corporation %R 10.1155/2014/540363 %X Structural health monitoring (SHM) has gained considerable attention as a tool for monitoring the health of civil infrastructure. For bridge infrastructure, previous methods have focused on the detection of localized damage through modal parameters extracted from the longitudinal direction of the structure. This paper investigates a new damage detection method based on the change in the first vertical mode extracted from the transverse direction of the bridge. The mode is determined through application of modal curve fitting to frequency response functions (FRFs) that are formed using vertical response data obtained in the direction perpendicular to the bridge¡¯s longitudinal axis. Using this method, both local damage and global damage in the bridge reveal themselves as having a localized effect on the bridge response. Furthermore, damage is revealed in such a way that it enables differentiation of the damage types. To demonstrate the effectiveness of the method, modal parameters were extracted from acceleration data obtained from a finite element model of a full bridge. Analysis of the modal parameters showed that the proposed approach could not only detect both local and global bridge damage, but could also differentiate between damage types using only one mode shape. The proposed method was compared to a previously developed SHM method. 1. Introduction Structural health monitoring (SHM) has gained considerable attention in recent years as a tool used to monitor the health state of civil infrastructure. It is based on the understanding that physical or mechanical degradation will change a structure¡¯s performance over time [1]. Most dynamic SHM methods are based on a set of vibration measurements acquired in the time domain. These measurements are then transformed to the frequency domain where they are used to identify damage directly (i.e., frequency response function methods), or indirectly through the derived modal parameters of the structure [2]. In the latter, damage is identified through a comparison of either the modal parameters, or structural models based on the modal parameters, before and after damage [3]. Ideally, information about the location and extent of damage can be used to determine the remaining useful life of the structure. To date, a multitude of experimental and numerical research investigations have been performed in damage identification. A comprehensive review of this work can be found in the literature [4¨C8]. With this in mind, the following literature survey will focus only on those research efforts immediately relevant to %U http://www.hindawi.com/journals/ace/2014/540363/