Effects of design and seismic parameters on horizontal displacement responses of sloped rolling‐type seismic isolators

Summary The influences of design parameters, including sloping angles of bearing plates and friction damping forces, together with seismic parameters, including corner periods and effective peak accelerations that are usually used for characterizing a design response spectrum, on the maximum horizontal displacement responses of sloped rolling‐type seismic isolators are numerically discussed in this study. Because the seismic isolators feature the constant acceleration control (or zero postelastic stiffness) performance, the equivalent linear model conventionally adopted in the equivalent lateral force procedure might not be adequate for predicting their maximum horizontal displacement response under a given seismic demand. Therefore, considering a small number to a large number of coefficients, several statistics‐based empirical formulas that are able to approximate their maximum horizontal displacement response are proposed. Not only the accuracy but also the conservative property of the proposed empirical formulas are discussed by comparing their predictions with the nonlinear response history analysis results. To efficiently determine the horizontal displacement capacity of sloped rolling‐type seismic isolators during the preliminary design stage, the statistics‐based empirical formula considering a reasonable number of coefficients is recommended.