【摘要】 考虑地基柔性的影响,使用SAP2000有限元程序分别建立了墩底固结和墩底六弹簧约束的桥墩模型,采用均匀加速度、第一阶振型和前三阶振型组合等3种水平侧向力加载模式分别对模型进行了推倒分析,并对比分析了不同墩高对计算结果的影响。通过对模型动力特性和推倒分析结果的对比分析表明,地基柔性不但延长了桥墩的自振周期,还对其振型和推倒曲线有着重要影响;对梁式桥梁结构进行推倒分析时不宜采用一阶模态向量分布加载模式;对于墩高较低、由第一阶振型控制的桥墩可采用均匀加速度和按一阶振型计算出的水平地震力分布模式进行推倒分析,墩高较高时,采用振型组合的加载模式更为合理。更多还原

【Abstract】 Considering the influence of foundation flexible,two sorts of pier model with various bottom constraints are established using SAP2000 finite element program.One model is fixed in the bottom and the other is restrained with six springs.Three different lateral load patterns,such as uniform acceleration,the first order mode and combination of top three modes are adopted in pushover analysis.The influence of different height of the pier on the calculated results is analyzed.The comparative analysis results show that flexible foundation not only extends the natural vibration period but also affects the vibration model and pushover curve notably.Using the first order mode is not recommended in pushover analysis for girder-type bridge structures.Uniform acceleration and the first mode of horizontal seismic force patterns can be used in pushover analysis for lower piers.And it is more reasonable to use multi-mode combination lateral load patterns for higher piers.更多还原