Elastically supported cantilever beam subjected to nonstationary seismic excitation

✍ Scribed by Fu, Gongkang

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 253 KB
• Volume: 27
• Category: Article
• ISSN: 0098-8847
• DOI: 10.1002/(sici)1096-9845(199809)27:9<977::aid-eqe769>3.0.co;2-n

✦ Synopsis

The dynamic behaviour of bridge piers under seismic load is studied here in the context of random vibration. The earthquake excitation is modelled as white noise filtered by the Clough-Penzien filter in cascade with modulation accounting for intensity non-stationarity. The bridge pier modelled as an elastically supported cantilever beam with a lumped mass at the top. An analytical solution is presented for the response statistics, which may be used to develop probabilistic seismic response spectra for design. It is found that the first two modes of the pier approach to rigidbody motion when the stiffness of the elastic support decreases. Seismic responses increase with the top mass, resulting in significantly high displacement and shear but negligible moment at the top, and higher shear and moment at the base. Lower stiffness of the elastic support increases the pier top displacement and moment responses, but may increase or reduce shear responses. The probabilistic spectrum of the relative displacement between the bridge superstructure and the pier top may depend on the two systems' relative modal properties.