Seismic response analysis of frame structures with uneven settlement of foundation considering soil-structure interaction

Abstract

Uneven settlement of foundation (USF) has a significant effect on the seismic response of rigid foundation structures. However, the main reason for USF is that the balance between superstructure and site soil is failure. For investigating seismic response characteristics of the USF structure considering soil-structure interaction (SSI), USF closer to reality is achieved by nonlinear direct integration method and Stage-Construction method. And the model reliability is verified by Sway-Rocking model and Lagrange energy method. Five different models, three seismic intensities, and different values of USF are performed. The natural period, inter-story drift ratios, the plastic hinges rate, and torsional angles are extracted to investigate structural seismic response. The results show that the effect of SSI on the magnitude of increase in structural inter-story drift ratio is not monotonous with the increase of USF in the presence of earthquakes. The USF structure considering SSI may significantly affect its seismic response, and will suffer more structural damage compared to the rigid foundation and the even settlement foundation. The rigid foundation structure with large value of USF leads to severe stretching on the settlement area and increases damage to the structure. Finally, the USF structures have relatively large torsional angles at the top story, and will exhibit significant torsional behavior. Hence, it is necessary and reasonable to consider SSI in the seismic design of USF structures. The research results can provide some references for seismic design.

Keywords

• Soil-structure interaction
• Uneven settlement of foundation
• Seismic response
• Torsion effects
• Seismic damage