The need to build tall buildings has been increasing worldwide, creating new challenges in earthquake engineering and design. Many of the current analysis methods cannot be extrapolated beyond the definition under which they were established. Prior studies and existing seismic design guidelines have indicated that the current fixed-base hypothesis for evaluating the seismic response of structures is not sufficient to properly represent the boundary conditions and behavior of tall buildings with basement levels. Studies of soil-structure interaction (SSI) for tall buildings have, however, typically been inconclusive. It is not clear under which conditions consideration of soil-basement-structure interaction (SBSI) is necessary for the design of the superstructure, foundation, and basement levels and when it can safely be avoided. Given the rising demand, it is essential to evaluate the relation of global system variables such as the basement depth, structure height, and soil characteristics with the building's response via numerical and experimental modeling. Therefore, an experimental-numerical approach is presented to better understand the seismic response of tall buildings with basement levels, considering explicit SBSI modeling. Chilean tall buildings and soil conditions are used as study cases, analyzed using nonlinear finite element analyses in conjunction with results from centrifuge experiments. The results show how seismic response parameters and modal characteristics, such as inter-story drifts, shear force, bending moment, natural frequencies, and damping ratios, change when SBSI is appropriately incorporated. The results point to the importance of considering soil-basement-interaction effects to evaluate the seismic response of tall buildings with basement levels and avoid unsafe estimations or the need for overdesign.
Bibliographical noteFunding Information:
We would like to acknowledge the Chilean National Commission for Science and Technology (CONICYT) for the financial support provided to the first author through grant CONICYT/Doctorado Nacional/2017–21170446, and the Chilean National Agency for Research and Development (ANID) for the support provided through Fondecyt Regular 1220796. We also extend appreciation to Dr. Kenneth Gillis and Ms. Christina Jones for their comprehensive recording and sharing of the centrifuge experimental results used during numerical model validation in this paper. We also thank Mr. Francisco Ruz and Mr. Ian Watt for sharing the data of actual buildings and geotechnical conditions used to generate the numerical models of the more realistic cases.
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- Seismic parameters
- Seismic response
- Soil-structure interaction
- Tall buildings