系梁对哑铃型高桩承台基础抗震性能影响

针对我国大跨度桥梁目前常用的哑铃型高桩承台基础，分析了系梁对其地震反应的影响因素，采用反应谱分析方法重点讨论了在工程可行的几何尺寸范围内，系梁轴向刚度和抗弯刚度对哑铃型高桩承台基础的地震反应影响规律，进一步讨论了系梁底桩基对系梁刚度的影响。结果表明：设置系梁后，系梁轴向刚度和抗弯刚度会对哑铃型高桩承台基础的地震反应产生较大影响，但在工程可行几何尺寸范围内，系梁轴向刚度的变化对其影响不大，而抗弯刚度的变化对其影响较大，且抗弯刚度越大对基础抗震越有利。在系梁底布置桩基可有效提高系梁的刚度。

Influence of tie-beam on seismic response of a dumbbell shaped elevated pile cap foundation

The influence of tie-beam on the seismic response of dumbbell shaped elevated pile-cap foundation was analysed, which was used widely in long span bridge in china at present. The effects of tie-beam stiffness was selectively analysed using response spectrum method considering the dimensions within the limit of engineering feasibility, furthermore, the effects of the pile(s) assembled under the tie-beam on its stiffness was discussed. The results show that the seismic response was influenced large by both the axial stiffness and bending stiffness when the tie-beam was built, but it was affected little by the former and large by the latter when they were changed in the engineering feasibility limit, and the latter was more rigid more better. The bending stiffness was improved by the pile(s) under the tie-beam.