The Seismic Response Of LRB Isolation Bridges Under Transverse Earthquake

The investigation of seismic damage of bridges indicates that it takes place beam's falling and pier's collapse not only at longitudinal bridges but also at transverse bridge. But, we paid more attention to longitudinal earthquake than to transverse earthquake in the past seismic design.With the seismic research developing, the longitudinal seismic damage can be reduced by set damping-isolation device, set energy-dissipation device or raise the ductility of pier. Single-column piers are widely used in urban bridges;they are liable to collapse under transverse earthquake due to their structure weakness. The seismic damage in recent years indicates that it should pay enough attention to the transverse earthquake. In 1995, the serious damage of piers of many urban bridges was caused by transverse earthquake in the powerful Osaka and Kobe earthquake of Japan. So it is necessary to research deep on transverse earthquake, thus clarify the basic reason causing the bridge to destroy under transverse earthquake.The paper presents dynamic analytic model of isolated bridge. Base on the model and considering multi-parameter effect, a large quantity of calculation and theoretical analysis are carried out to obtain the laws of the transverse response of isolated bridge. During the analysis, different factors, such as seismic site, intensity, link stiffness of LRB, and bridge structures themselves are considered.