高墩桥梁的P-Δ效应及简化计算方法

Effects and Simplified Method of P-delta of Tall Pier Bridge

基于多自由度分析模型,通过初始刚度矩阵中叠加影响刚度矩阵考虑P-Δ效应的影响,研究了P-Δ效应对铁路高墩弹性地震反应的影响。以墩顶位移与墩底弯矩为指标,通过改变梁体重与墩高来考查P-Δ效应的变化规律,引入稳定指数定量分析了P-Δ效应的放大效果。结果表明,地震作用下P-Δ效应会增大高墩的墩顶位移与墩底弯矩,墩顶位移与墩底弯矩的增大率与稳定指数有一定的相关性,可以用稳定指数近似表示。

Effects of P-delta on the elastic seismic response of tall railway pier is studied based on the multi-degree freedom analysis model and through the superposition of the stiffness matrix in the primary stiffness matrix to consider the effect of P-delta.Taking the displacement of pier top and the moment of pier base as the index,the change of beam weight and pier height investigates the variation law,and the stability index is introduced to quantitatively analyze the magnification of P-delta effects.The results show that P-delta effects will increase the displacement of pier top and the moment of pier base of the tall pier under earthquake,and the magnification of pier top displacement and the pier base moment has some relevance with stability index,which can be approximated with a stability index.