UC San Diego

In recent years, the conditions of aging transportation infrastructure have drawn great attention to the maintenance and inspection of highway bridges. With the increasing importance of life-lines, such as highways, to the national economy and the well-being of the nation, there is a need to maximize the degree of mobility of the system. This requires not just routine, or critical event (such as an earthquake) based, inspections, but rather a means of continuous monitoring of a structure to provide an assessment of changes as a function of time and an early warning of an unsafe condition using real-time data. A promising technique, namely Vibration-based Structural Health Monitoring, has been proposed to address this problem. The basic premise of Vibration-Based Structural Health Monitoring is that changes in structural characteristics, such as mass, stiffness and damping, will affect the global vibrational response of the structure. Thus, by studying the changes in measured structural vibration behavior and in essence solving an inverse problem, the unknown changes of structural properties can be identified. A new vibration-based structural health monitoring methodology for highway bridges is proposed in this dissertation. Progress is made in several key areas, including operation modal analysis, damage localization and finite element model updating. The real-world implementation of a health monitoring system on a highway bridge demonstrated the effectiveness of the proposed technique and pointed out directions for future research