不同类型地震动作用下双柱墩梁桥的隔震控制

Isolation control of double-column pier beam bridge under far-field harmonic-alike ground motions

远场类谐和地震动更易引起桥梁破坏,为此,以某双柱墩梁桥为结构,分别建立抗震模型与隔震模型,分析其在远场类谐和地震动与普通地震动下的动力响应,揭示隔震后主梁、墩柱和支座的地震响应变化。此外,分析SSI效应时隔震梁桥的主梁位移、桥墩弯矩和剪力以及墩顶位移变化规律。结果表明;远场类谐和地震动下隔震可减少主梁纵桥向位移防止主梁与桥台碰撞,当类谐和地震动峰值加速度较大时,隔震梁桥桥墩横桥向地震响应较抗震结构会有所增大,带来不利影响;考虑桩-土作用的梁桥墩-系梁连接点纵向弯矩随着桩-土刚度减小而增大,墩-系梁连接点容易发生纵向弯曲破坏。

The beam bridges subjected to far-field harmonic-alike ground motions were more likely to cause bridge damage.Therefore,based the actual double-column pier girder bridge,the seismic model and the isolation model were established to analyze the dynamic response of the seismic and isolation beam bridge under far-field harmonic-alike ground motions,revealing the damage mechanism of main beams,pier columns and supports after seismic isolation.Further,the main girder displacement,pier bending moment,the force and the displacement of the pier top after considering the SSI effect were analyzed.It shows that the longitudinal displacement of the main girder can be reduced to prevent the main girder from colliding with the bridge abutment under the action of far-field harmonic ground motion.When the peak acceleration of the harmonic-like ground motion is large,the seismic response of the seismic isolation beam bridge pier in the transverse direction is better than that of the seismic structure,it will increase and bring adverse effects.After considering the pile-soil interaction,the longitudinal bending moment and the displacement of the pier top of the pier-tie beam connection point increase with the decrease of the pile-soil stiffness,and the pier-tie beam connection point is prone to longitudinal bending failure.