Comparison between seismic analysis of twisting and regular 52-story towers considering soil-structure interaction

A dynamic analysis of both twisting and regular towers is carried out to determine the results of considering soil-structure interaction (SSI) on high-rise buildings. In addition, the difference between the seismic performance of using twisting towers over regular ones is investigated. The twisting tower is a simulation of the Evolution Tower (Moscow). The towers' skeletons consist of RC elements and rest on a reinforced concrete piled-raft foundation. The soil model is considered as multi-layered with the same soil properties as the zone chosen for the analysis (New Mansoura City, Egypt). The only difference between both towers is their shape in elevation. The whole system is modelled and analyzed in a single step as one full 3D model, which is known as the direct approach in SSI. All analyses are carried out using finite-element software (Midas GTS NX). Dynamic output responses due to three records of seismic loads are proposed and presented in some graphs. Based on the results, it is concluded that SSI has a considerable effect on the dynamic response of tall buildings mainly because of the foundation flexibility, as it leads to lengthening the vibration period, increasing the story drift and the base shear for both cases.