Accuracy of analytical models to predict primary and secondary system response in seismically isolated buildings

Abstract

Seismic isolation is generally considered an effective earthquake protection strategy. As application of seismic isolation increases, decisions on the use of one particular isolator versus another isolator increasingly depend on computed responses with complex analytical models. Accordingly, validation of analytical models to predict primary (structural) and secondary system (non-structural component) response in seismically isolated buildings becomes very important. This paper presents comparisons of experimental and analytical results on the primary and secondary system response of a building model in order to provide information on the accuracy of the predicted response. The tested model was con gured as a 6-story building at quarter length scale in a moment-frame con guration, and with the following seismic isolation systems: a) Low damping elastomeric bearings with and without linear or nonlinear viscous dampers, b) Single Friction Pendulum (FP) bearings with and without linear or nonlinear viscous dampers, and c) Lead-rubber bearings. Response quantities compared include story drifts and isolator shear forces and displacements for the primary system, and peak oor total velocities and oor response spectra that relate to secondary system response. This paper presents samples results out of a total of 288 comparisons of experimental and analytical results presented in an MCEER report. It is shown that the primary and secondary system response is computed with su cient accuracy by the analytical models but some response quantities may be underestimated or overestimated by signi cant amounts.

Experimental Parametric Study and Phenomenological Modeling of a Deformable Rolling Seismic Isolator

“…Overall, the observed accuracy of these predictions is also consistent with the results obtained by Ipek, Wolff, and Constantinou ( 2021 ) for structures with different seismic isolation systems. It is noted that, for real buildings and more complex, three-dimensional seismic excitation, the error of the analytical prediction is expected to increase.…”

“…It is noted that, for real buildings and more complex, three-dimensional seismic excitation, the error of the analytical prediction is expected to increase. The error of the analyses presented both in this paper and in the study of Ipek, Wolff, and Constantinou ( 2021 ) is the result of uncertainties in the behavior of the tested structures, which can be accounted for in analysis and design using bounding methods of analysis.…”