Peak Sliding Displacements of Sliding Base Structures Subjected to Earthquake Excitation

Sliding base (SB) systems are attractive options for protecting low-rise buildings in high-seismicity undeveloped rural areas. This study focuses on the peak sliding displacements (PSDs) of SB structures subjected to three-component earthquake excitations. Both the PSDs in the two principal directions and that with respect to the origin were investigated. The peak ground velocity (PGV) was selected as the ground-motion intensity measure (IM) because of its high correlation with the PSD and simplicity of use in design. The effect of the vertical ground-motion component on the PSDs is negligible. At a given level of normalized PGV, the probability distribution of the normalized PSD approximately follows a lognormal distribution. The relationship between the median normalized PSD and normalized PGV in each principal direction is close to that with respect to the origin, and the influence of the superstructure natural period and mass ratio is insignificant. When the normalized PGV is small, the median normalized PSDs corresponding to the nonpulse-like and near-fault pulse-like records are close to each other; when the normalized PGV exceeds a certain value (approximately 6–8 m/s), the median normalized PSD for the pulse-like records begins to exceed that for the nonpulse-like records, with the difference increasing monotonically as the normalized PGV increases. The lognormal standard deviations of the normalized PSDs are generally between 0.4 and 0.6 except for some cases in which the normalized PGV is small. Based on the numerical results, simplified equations were developed for generating fragility curves.