Maximum Superstructure Response of Sliding-Base Structures under Earthquake Excitation

Sliding-base (SB) systems are efficient for protecting low-rise buildings in high-seismicity rural areas. The normalized peak pseudoacceleration (NPPA) of one-story SB structures under three-component earthquake excitation and its dependency on various structural and ground motion characteristics are investigated herein. The relationships between the NPPA and the normalized peak ground acceleration (PGA) are basically identical for both orthogonal horizontal directions. The vertical earthquake component can either increase or reduce the horizontal superstructure response; for most cases, its effect is negligible. The NPPA first increases and then decreases as the natural period of the superstructure increases; the responses at the period of the maximum mean NPPA can be used to represent the responses of possible SB structures. The ratio of the natural periods in the two orthogonal horizontal directions and the difference between the static and dynamic friction coefficients affect the superstructure responses of SB structures little. The earthquake magnitude and source-to-site distance also exhibit negligible effects. The superstructure responses under pulse-like ground motions are generally smaller than those under non-pulse-like ground motions. Local site conditions affect the superstructure response; sites on softer soils display larger NPPAs. However, this effect decreases rapidly as the normalized PGA increases. For a given site class, mass ratio, and normalized PGA, the NPPA probability distribution approximately follows a normal distribution. Simplified equations with associated regression coefficients were proposed to estimate the mean values and coefficients of variation (COVs) of NPPAs. These equations can be further used to predict the NPPA corresponding to any probability of nonexceedance.