高速铁路大跨度梁拱组合桥抗震分析

Seismic Analysis of Large Span Beam-arch Composite Bridge

大跨度梁拱组合桥由于竖向刚度较大、梁高较小成为高速铁路常用桥型。为研究梁拱组合桥的地震反应特点,对一(60+128+60)m梁拱组合桥建立动力有限元分析模型,并进行特征值分析,根据其振动模态分析梁拱组合桥的振动特点,并采用时程分析方法对该桥进行弹性和弹塑性地震反应分析。结果表明:该桥在多遇地震下满足截面偏心距要求;在罕遇地震下满足延性率要求;结构满足"小震不坏、大震不倒"的抗震设防目标。

Due to its large vertical stiffness and relatively small beam height,large span beam-arch composite bridge is widely applied to high-speed railway. To study the seismic response characteristics of beam-arch composite bridge,a seismic analysis finite element model of a（ 60 ＋ 128 ＋ 60） m beam arch composite bridge is established and its vibration characteristics are analyzed according to the modal analysis. Time-history method is employed in the elastic and elastic-plastic analysis of the beam-arch composite bridge. The results indicate that the bridge meets the demands of section eccentricity under low-level earthquake and ductility ratio under high-level earthquake. The bridge structure proves effective in meeting the demand of＂no damage under low-level earthquake and no collapse under high-level earthquake＂.