中小跨径桥梁座式桥台抗震性能参数敏感性分析

Sensitivity analysis for seismic performance parameters of seat abutment of small and medium span bridges

采用pushover分析方法研究中小跨径桥梁座式桥台构造参数对自身抗震性能的影响,基于前人研究成果和座式桥台统计数据,选取背墙箍筋间距、台帽水平拉筋间距、背墙厚度及主梁作用高度作为试验因素,进行4因素3水平的正交数值模拟试验,选取桥台的峰值位移、峰值荷载、平均刚度及位移延性系数4个指标作为反映其抗震性能的目标函数,通过极差分析得出各桥台构造参数对桥台抗震性能指标的敏感性。结果表明:对桥台的峰值荷载及平均刚度而言,背墙厚度对其影响最大、最敏感,背墙厚度的增大可使峰值荷载和平均刚度分别增大29.8%和33.4%;对于桥台的峰值位移及位移延性,主梁作用高度和背墙箍筋间距对其影响较大,主梁作用高度和背墙箍筋间距的增大使桥台峰值位移变化幅度分别不超过9.2%和11%,主梁作用高度和背墙箍筋间距的增大使桥台位移延性系数变化幅度分别不超过10%和6.7%。

The influence of structural parameters of seat abutment of small and medium span bridges on their seismic performance was studied by the pushover analysis method.The orthogonal numerical simulation test of four factors and three levels was carried out by selecting the stirrup spacing of abutment backwall,the horizontal bar spacing of abutment cap,the thickness of backwall,and the action height of main beam as the test factors.The peak displacement,peak load,average stiffness,and displacement ductility coefficient of the abutment were selected as the objective function to reflect the seismic performance.Through range analysis,the sensitivity of each parameter to seismic performance indexes of the abutment was obtained.The results showed that the thickness of backwall has the greatest influence on the peak load and average stiffness of abutment.With the increase of backwall thickness,the peak load and average stiffness increase by 29.8%and 33.4%,respectively.The action height of main beam and the stirrup spacing of backwall have a great impact on the peak displacement and displacement ductility of abutment.With the increase of action height of main beam and stirrup spacing of backwall,the variation of abutment peak displacement is not more than 9.2%and 11%,and the variation of abutment displacement ductility coefficient is not more than 10%and 6.7%.