墩高对连续梁桥抗震性能的影响

以南水北调中线工程中某预应力混凝土连续梁桥为例,采用有限元程序MIDAS建立了考虑和不考虑桩土作用的两种有限元计算模型,选取5,10,15,20,25 m等5个墩身高度,采用反应谱分析法,分析在顺桥向及横桥向地震输入下不同墩身高度对结构的自振周期、制动墩和非制动墩的墩顶位移、墩底内力、墩顶内力的影响规律,以及桩土作用效应随墩身高度的变化规律,可为同类桥梁结构的抗震设计提供理论依据.

Influence of Pier Height on the Seismic Behaviors of Continuous-beam Bridge

Taking the pre-stressed concrete continuous-beam bridge in the Central Project of South-to-north Water Transfer Engineering as an example, two finite element numerical models were built considering and without considering the influence of pile-soil action. The 5 different pier heights of 5 m, 10 m, 15 m, 20 m and 25 m were selected, the earthquake actions along and transverse the bridge di- rections were input and the response spectrum analytical method was adopted. Based on the calculation, the effects of pier height on the self-vibration period, the pier top displacements of control and un-control piers and the internal forces at pier bottom and pier top were analyzed, and the changes of pile-soil action with pier height were also discussed. The results would provide a theoretical basis for the seismic design of the similar bridges.