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为研究长周期地震波对高墩大跨连续刚构桥地震响应的影响,基于OpenSEES平台建立了考虑材料和几何双重非线性的全桥动力分析模型,针对远场谐和型、近断层脉冲型和近断层滑冲型3类长周期地震波,与现行规范协调的普通地震波和人工波等5类共20条波进行非线性时程对比研究。结果表明:长周期地震动对高墩关键截面内力响应的放大作用非常明显,低频成分最丰富的远场谐和型地震波的内力计算值为普通波和人工波的2~4倍;而对高墩位移响应的放大作用比内力更显著,远场谐和型地震波的墩顶位移值超过普通波和人工波的20倍,导致支座剪断破坏;以现行规范反应谱为基准进行抗震设计,会大大低估高墩桥梁的地震内力和位移响应需求,引发灾难性的后果。
In order to study the effect of long-period seismic wave on the seismic response of long-span continuous rigid frame bridge with high piers, a full-bridge dynamic analysis model considering the dual nonlinearity of material and geometry was established based on OpenSEES platform. For far-field harmonic, near-fault impulsive and Near-fault slip-type 3 kinds of long-period seismic waves, with the current norms in coordination with ordinary seismic waves and artificial waves of 5 types of a total of 20 waves for nonlinear time history comparative study. The results show that the effect of long-period ground motion on the internal force response of the key section of high pier is obvious. The calculated internal force of the far-field harmonic seismic wave with the richest low-frequency component is 2 to 4 times of that of the normal and artificial waves. The displacement effect of pier response is more pronounced than that of internal force, and the displacement of far-field harmonic seismic wave is more than 20 times that of normal wave and artificial wave, which leads to the shear failure of bearing. According to the current standard response spectrum, seismic design Greatly underestimated the seismic internal forces and displacement response requirements of high pier bridge, triggering disastrous consequences.