Field Testing of Bridge Design and Retrofit Concepts. Part 1 of 2. Field Testingand Dynamic Analysis of a Four-Span Seismically Isolated Viaduct in Walnut Creek, California

摘要

The opportunity for the field testing of an isolated viaduct arose out of thedemolition and reconstruction of the I-680/R-24 interchange in Walnut Creek, California. The southern section of the temporary separator bridge is seismically isolated, and this portion was the subject of a three-phase field study. This viaduct is the first new bridge in California to be seismically isolated. The primary objective of this investigation was to collect field data for the determination of the dynamic properties (mode shapes, modal frequencies, and damping ratios) of the viaduct, to assess the contribution of different structural components to the overall flexibility and damping characteristics of the structure, and to conduct analytical studies to verify the experimentally computed dynamic properties.