Direct Method for Generating Floor Response Spectra considering Soil-Structure Interaction

• Published in: Journal of earthquake engineering : JEE Vol. 26; no. 10; pp. 4956 - 4976
• Main Authors: Jiang, Wei, Zhou, Yang, Xie, Wei-Chau, Pandey, Mahesh D.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 27.07.2022; Taylor & Francis Ltd
• Subjects: Direct Method; Floor Response Spectrum; Floors; Foundation Level Input Response Spectra; Methods; Nuclear energy; Nuclear power plants; Probability theory; Response spectra; Seismic Analysis; Soil; Soil dynamics; Soil-Structure Interaction; Spectra; Stiffness matrix; Transfer matrices
• ISSN: 1363-2469; 1559-808X
• DOI: 10.1080/13632469.2020.1852137

A methodology is developed for generating floor response spectra (FRS) considering the effect of dynamic soil-structure interaction (SSI) based on the substructure technique and a recently-developed direct spectra-to-spectra method. Dynamic stiffness matrix of a three-dimensional structure with a rigid foundation subject to three translational and three rotational base excitations is derived, and is expressed in terms of the modal information of the structure. A transfer matrix, depending on the dynamic stiffness matrices of the structure-foundation system and generalized soil springs, is developed to modify the tri-directional response spectra at the foundation level of free-field (FIRS) in soil medium. The modified response spectra, called foundation level input response spectra (FLIRS), are used as the input to the fixed-base structure to generate FRS using the direct spectra-to-spectra method. Numerical examples of a reactor building and a service building in nuclear power plants demonstrate the accuracy and efficiency of the proposed method. FRS with % and % Non-Exceedance Probability (NEP) given by the proposed method agree well with the FRS obtained from a large number of time history analyses. Furthermore, the effect of SSI on FRS is studied, the physical meaning, and the advantages of the proposed method are highlighted.