Instrumentation and Field Testing of Bridges – Case Studies

This paper discussed the identification of the dynamic properties of instrumented bridges and how this information can be used to better understand their behavior during strong earthquakes. Results obtained from ambient vibration tests are combined with those obtained from the permanent instrumentation to help develop reliable computer models that can, in turn, be used to estimate their behavior under much more severe ground shaking observed so far at the location of the bridges. Three case studies are presented and discussed in this paper. The first two studies are about permanently instrumented bridges in California and the third one is about an instrumented bridge in Taiwan. The first two cases combine results from ambient vibration tests and results from the analysis of recorded earthquakes, while the third one investigates in detail the seismic response of a skewed bridge.