A probabilistic performance-based risk assessment approach for seismic pounding with efficient application to linear systems

Earthquake ground motion excitation can induce pounding in adjacent buildings with inadequate separation distance. The corresponding risk is particularly relevant in densely inhabited metropolitan areas, due to the usually limited separation distance between adjacent buildings.Existing procedures to determine a minimum separation distance needed to avoid seismic pounding are based on approximations of the peak relative horizontal displacement between adjacent buildings, and are characterized by unknown safety levels. The present study proposes a probabilistic performance-based procedure for assessing the mean annual frequency of pounding between adjacent buildings. An efficient combination of analytical and simulation techniques is defined for the calculation of the pounding risk under the assumptions of linear elastic behavior for the buildings and of non-stationary Gaussian input ground motion.The proposed methodology is illustrated by estimating the probability of pounding between linear single-degree-of-freedom systems with deterministic and uncertain properties. Furthermore, the capabilities of the proposed method are demonstrated by assessing the effectiveness of the use of viscous dampers, according to different retrofit schemes, in reducing the pounding probability of adjacent buildings modeled as linear elastic multi-degree-of-freedom systems. The results obtained based on the proposed methodology are validated against purely numerical simulation results.