Available at: https://digitalcommons.calpoly.edu/theses/3100
Date of Award
6-2025
Degree Name
MS in Civil and Environmental Engineering
Department/Program
Civil and Environmental Engineering
College
College of Engineering
Advisor
Giovanni De Francesco
Advisor Department
Civil and Environmental Engineering
Advisor College
College of Engineering
Abstract
This study presents a statistical analysis of the seismic demand of mid-story isolated structures in linearized elastic conditions. The assumed earthquake database consists of 228 ground motions recorded in California from earthquakes with magnitudes greater than 6. A three-degree-of-freedom modeling approach is adopted, and the seismic demands of the substructure, superstructure, and isolation system are determined for varying isolated mass and stiffness ratios. The seismic demand of mid-story isolated structures at the isolation level is expressed in terms of the response of an idealized isolated superstructure supposed to be on the ground, while the demands on the substructure and superstructure are expressed relative to their respective fixed-base counterparts. The results are used to validate the analytical predictions obtained through modal analysis procedures and to highlight areas for future improvement. The expressions of the normalized demands are implemented in a practice-oriented design framework that enables the seismic demand of mid-story isolated structures to be quantified based on the independent responses of the substructure and the isolated superstructure.