UBC Theses and Dissertations
Seismic structural health monitoring of bridges Mirza, Kian
Seismic Structural Health Monitoring (SSHM) is defined here as the process to determine the status of serviceability of a structure immediately after an earthquake. This can be done remotely via the Internet or any suitable communication link. In this study, a procedure was introduced for SSHM of bridges with limited strong motion instrumentation. This procedure is developed and presented in a flowchart format, which can be easily implemented as a user-friendly software. The SSHM Procedure is able to analyze the recorded motions by the sensors installed on a bridge after an earthquake and determine the serviceability status of the structure. The level of serviceability can be easily determined by the procedure as Safe, Limited or Out of Service. It can also determine the location and severity of the damages sustained, if any. This procedure is a combination of the results of two main components: those from the use of a structural health monitoring (SHM) technique and those from a series of nonlinear structural analyses. This combination can minimize the errors and misinterpretation of results, which may arise from the independent implementation of each component. The Damage Index Method (DIM) is the SHM method used in this study, and has been critically reviewed. This is the first time the DIM has been used on a real bridge with very limited number of sensors. An actual bridge (the Painter Street Overpass Bridge located in California), which has been instrumented and has experienced more than ten earthquakes of different intensities was selected as a case study. The proposed SSHM was implemented to assess the status of the bridge for selected earthquakes. Complementary strong motion records were generated to induce artificial levels of damage to a well calibrated finite element model of the bridge, and the results from these analyses were used to further assess the effectiveness of the proposed procedure. The proposed SSHM procedure is shown to be accurate, rational and relatively easy to implement in engineering practice.
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