钢管混凝土叠合柱式桥墩考虑桩土作用的地震效应分析

为减小桥墩阻水面积，南水北调中线工程跨主干渠大油村北桥中墩墩身采用圆形钢管混凝土叠合柱，以避开阻水超限的普通钢筋混凝土桩柱式结构。探讨考虑桩土相互作用的三种模型并对计算结果进行了对比分析。发现等效三弹簧模型能较好地模拟桩土相互作用下桩基的地震反应，同时说明叠合柱能以较小的直径满足既定承载能力的要求，比普通钢筋混凝土桩柱式结构具有更好的经济性和抗震性能。

Analysis on Seismic Effect of Pile-soil Action against CFST and Concrete Composite Column Pier

In order to reduce the water resistance area of bridge pier, the intermediate pier of the Dayoucun North Bridge crossing the trunk cannel of the Central Line of the South-to-North Water Diversion Project was designed as a circular concrete-filled steel tube （CFST） and concrete composite column pier. Three models considering the interaction between pile and soil are discussed and the calculating results are compared and analyzed. Then it is found that the equivalent spring model can simulate the seismic response of the pile foundation under pile-soil interaction better; while it is showed that the composite pier can meet the existing load bearing capacity requirement just with small diameter and has better economy and seismic resistance performance than those of the common concrete pile column pier.