【摘要】 从连续斜交梁桥震后普遍的落梁震害和平面旋转现象出发,提出一种带碰撞单元并考虑竖向、水平及扭转刚度的单梁简化模型。以一座3 m×30 m连续斜交梁桥为工程背景,通过动力特性分析和地震下考虑碰撞效应的非线性时程分析,将简化模型的计算结果与精细化板单元有限元模型的结果进行对比。研究结果表明:该简化模型不仅能较准确地计算结构的动力特性,还能较准确计算斜交梁桥在碰撞下的非线性位移,反应碰撞后桥面的平面旋转现象;碰撞刚度在一定范围内对非线性位移不敏感,可采用主梁轴向刚度为碰撞刚度,但梁端截面最外缘的碰撞单元对非线性位移较敏感,需保证在梁端截面最外缘处设置碰撞单元。更多还原

【Abstract】 A seismic simplified model of a 3-span bridge with the skew angle of 60° was established using the pounding elements and a single girder considering its vertical,horizontal and torsional stiffness.By employing modal analysis and nonlinear time-history analysis during earthquake,the comparison is made between the results of the simplified model and a detailed model with plate elements.The results show that the simplified model can accurately calculate the structure dynamic properties,revealing the correct nonlinear displacements and deck rotation because of the pounding effect.The stiffness of pounding element is insensible to the girder displacements,and the axial stiffness of the girder can be used as the pounding stiffness.But the arrangement of pounding elements at the outmost point of the beam-end section is sensible to the nonlinear displacements which must be applied in the analysis model.更多还原