某高层建筑-箱型基础动力响应分析

Dynamic response analysis of box foundation of a high-rise building

文章考虑土-结构动力相互作用,利用有限元分析软件ANSYS对地震激励下的某超限高层建筑箱型基础进行了数值模拟,并对其动力响应进行了分析。首先,通过静力分析验证模型的合理性,确保其计算精度,并分别输入地震激励EL-centro波、Kobe波和上海人工波,分析箱型基础在不同激励下的层间位移、内力变化。结果表明:在不同的地震波作用下,箱基整体呈现出剪切变形模式,层间位移以底层为最大,轴力、剪力和弯矩也均是底层柱最大,因而箱基底层视为薄弱层;顶层由于围岩性质、上部结构嵌固以及地震耦合效应的影响,也容易成为薄弱部位;在地基-箱型基础-上部结构共同作用体系中,上部结构的刚度以及周围土体的约束,使箱基的整体性得到了极大提升,从而在设计地震加速度作用下其各个部位都能够处于正常工作的弹性阶段;箱基的中柱受到地震波耦合作用的影响要显著于边柱。分析结果为今后超限建筑的抗震优化设计提供了一定的理论和设计依据。

The numerical simulation of box foundation of a high-rise building under seismic excitation was carried out by using the finite element analysis software ANSYS considering soil-structure dynamic interaction,and the dynamic response of the box foundation was analyzed.Firstly,the rationality of the model was verified by the static analysis,which ensured the accuracy of the calculation.Then the seismic excitation like EL-centro wave,Kobe wave and Shanghai artificial wave was inputted and the inter-story displacement and internal force variation of the box foundation were analyzed.The results showed that the shear deformation mode of the box foundation was showed under different seismic waves and the inter-story displacement,axial force,shear force and bending moment of the bottom layer were the largest,proving that the bottom layer was the weak layer;the top layer was also easy to become weak parts due to the nature of surrounding rock,the stiffness of superstructure and the coupling effect of earthquake;each part of the box foundation could be in the elastic stage of normal work under the design earthquake acceleration because of the better overall stability of the box foundation owing to the stiffness of the upper structure and the restraint of the surrounding soil mass in the foundation-box foundation-upper structure interaction system;the coupling of the seismic wave had a greater effect on the middle column of the box foundation than the side column.The analysis results provide some theoretical basis and design suggestions for the seismic design of similar buildings in the future.