Performance Analysis of Basement Fin Wall of the Shanghai Tower Based on the Interaction Between Pile-Raft Foundation and Superstructure

Abstract

Several advantages can be obtained by setting fin walls in the basement of super tall buildings. On one hand, the overall stiffness of foundation could be improved and then differential foundation settlement could be reduced. On the other hand, basement shear stiffness could be effectively increased and the ground floor could be set as the lateral support with appropriate percentage of basement fin walls. Besides, the fin walls can also increase punching resistance capacity for pile-raft foundation and can thus reduce the raft mat thickness. In order to assess the performance of fin wall of the Shanghai tower project, a three dimensional finite element model including piles, raft mat and the superstructure was firstly established. Two cases, including model with fin wall and model without fin wall, were considered, and the structural periods, story drift, internal forces of key members and differential deformation were obtained respectively. By considering the effect of concrete cracking and shrinkage, the performance of model with and without fin wall stiffness reduction was compared. Based on the above mentioned analysis, the mat support condition and construction process were considered for further analysis to evaluate the performance of fin wall. The key factors with the fin wall performance were thoroughly discussed in this study, and the analysis conclusions could be used as reference for the structural design of fin wall in super tall buildings.