Seismic Response Analysis Of Long Span Continuous Rigid Frame Bridges

Nowadays, most of seismic resist design codes of bridge are only suitable to small-span bridges. Seismic resist design of long-span bridges has no rule to follow, In china, seismic resist design codes of road is only suitable to girder bridges and arch bridges which of main span under 150 meters. So to all the long -span bridges, It's necessary to use calculation and analysis of seismic response signally.Compared to small - span bridges, long -span bridges are more complicated, we need to consider multi-support excitations and travel wave effect, different kinds of nonlinear factor and the interactions between pile-ground-structure and so on. Most of domestic theory of seismic resist design can't make full use of seismic resist design which decrease the effects of seismic resist design seriously. This paper covered some one characterization—travel wave effect.Seismic response spectrum ,Time-Histroy Analysis method and random method are general calculation way of seismic resist design.This paper describes the seismic response for long-span continuous rigid-framed bridge by using Seismic response spectrum theory and Time-History Analysis method. Conclusions can be derived, First point,longitudinal travel wave effect make seismic response of the bridge weaker, stress of beam can be increased; Second point,the response of displace under excitation of travel wave is approaching to response of displace under excitation of coincident wave gradually while wave speed is becoming bigger. When the wave speed is infinite, both response of displace and stress of beam should keep the same step to seismic response under excitation of coincident wave, Third point,the action of longitudinal seismic resist design to the bridge is smaller than that of lateral seismic resist design, Last point, removing longitudinal constraint of side piers, the effects of seismic response of the bridge can be decreased.