Dynamic soil-structure interaction effects on the seismic response of suspension bridges

✍ Scribed by Shrikhande, Manish; Gupta, Vinay K.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 220 KB
• Volume: 28
• Category: Article
• ISSN: 0098-8847
• DOI: 10.1002/(sici)1096-9845(199911)28:11<1383::aid-eqe874>3.0.co;2-e

✦ Synopsis

A stochastic approach has been formulated for the linear analysis of suspension bridges subjected to earthquake excitations. The transfer functions of various responses have been formulated while including the e!ects of dynamic Soil}Structure Interaction (SSI) via the use of the "xed-base modes of the structure. The excitation has been characterized by the &equivalent stationary' processes corresponding to the free-"eld motions at each support and by an assumed coherency function between these motions. The proposed formulation considers the non-stationarity in the structural response due to sudden application of excitation by considering (i) the time-dependent frequency response functions, and (ii) the order statistics formulation for the peak factors in evolutionary response processes. The formulation has been illustrated by analysing the seismic response of the Golden Gate bridge at San Francisco for two example excitations conforming to USNRC-speci"ed design spectra. The signi"cance of various governing parameters on the dynamic soil}structure interaction e!ects on the seismic response of suspension bridges has also been studied. It has been found that the contribution of the vertical component of ground motion to the bridge response increases with increasing soil compliance. Also, the extent to which the spatial variation of ground motion a!ects the bridge response depends on how signi"cant the SSI e!ects are.