桩-土-结构相互作用下网壳结构简化计算方法

基于桩-土相互作用中地基土的离散模型和有限元模型,采用空间S-R模型和整体有限元法分别建立桩-土-单层柱面网壳结构相互作用的简化模型和一体化模型,简化模型中将地基土以离散的弹簧单元模拟,通过与一体化模型的对比分析,探究空间S-R模型分析桩-土-结构相互作用下大跨空间结构的适用性和精确度。研究表明:采用空间S-R模型建立的简化模型能够较好地模拟网壳结构自振特性和网壳屋盖地震响应,便于工程应用。简化模型得到的网壳屋盖第一阶自振频率与一体化模型的计算误差在10%之内,在不同地震作用下,简化模型得到的网壳屋盖节点加速度峰值与一体化模型结果的最大误差为13.05%,位移最大值的最大误差为7.20%,杆件内力最大误差为9.59%。

SIMPLIFIED ANALYSIS METHOD OF A LATTICED SHELL CONSIDERING PILE-SOIL-STRUCTURE INTERACTION

Based on the finite element model and discrete model of soil surrounding pile,the space S- R model and finite element method were adopted to establish a simplified model and an integrative model,which contains a singlelayer cylindrical latticed shell,pile and its foundation soil. The soil was replaced with spring in the simplified model,and it was compared with the integrative model. The applicability and accuracy of the space S- R model for analyzing the large span space structure considering pile-soil-structure interaction( PSSI) were studied. The results showed that the simplified model could simulate natural vibration characteristic and seismic response of the shell fairly well,and it is convenient to be used in engineering. The error of the first order vibration frequency of the shell calculated by the simplified model was less than 10% compared with the results of the integrative model. The maximal error of the peak acceleration of node was 13. 05% when it subjected to earthquake loads. The maximal error of the nodal displacement was 7. 20%,and the maximal error of the internal force of the members was 9. 59%.