隔震双支座的不同模拟结果对比分析

Comparative Analysis of Different Simulation Results for Double Isolation Bearings

隔震建筑中往往出现单支墩下有双支座的情况,隔震分析时,设计人员将2个支座的刚度合并,等效为1个支座输入。文章基于平面力系平衡方程,结合规范要求及工程案例验证,在单支墩下真实布置双支座(双支座输入)和按单支座模拟(单支座等效输入)的两种输入方式下对比支座拉压应力的结果差异。分析结果表明:单支墩下设置双支座时,采用单支座等效输入的方式无法得到支座的真实拉压应力,特别是双支座布置方向上支墩仅单侧有梁的位置,在长期面压和大震拉应力验算时支座的真实拉压应力可能超过规范限值,此时应采用符合实际受力状态的双支座输入模型进行隔震分析。

There are often double bearings under a single pier in a seismic isolation building.In seismic isolation analysis,the designers combine the stiffness of two bearings,which is treated as the input of one bearing.Based on the equilibrium equation of the plane force system,as well as code requirements and engineering case verification,in this paper,the results of bearings’tension-compression stress in two input modes(namely double bearings under a single pier(double-bearing input)and single-bearing simulation(single-bearing equivalent input))were compared.The analysis results show that when double bearings are arranged under a single pier,the real tension-compression stress of the bearings cannot be obtained by using the single-bearing equivalent input mode.Especially at the position where there are beams only on one side of the pier in the layout direction of double bearings,the real tension-compression stress of the bearings may exceed the limit in the code during checking calculation of long-term surface pressure and large seismic tensile stress.In this case,the input model of double bearings conforming to the actual stressed state shall be used for seismic isolation analysis.