Torsional Pounding Effects on Seismic Response of Base‐Isolated Buildings: Predictive Capability of Earthquake Characteristics

ABSTRACT Pounding between adjacent structures during seismic events poses a significant threat to structural integrity, particularly for base‐isolated buildings. This risk is further compounded when considering the presence of torsion, which can exacerbate the detrimental effects of pounding. Accurate prediction of structural behavior under combined pounding and torsion is crucial for developing effective mitigation strategies. This study aims to address this critical issue by exploring the relationship between key earthquake parameters (peak ground acceleration [PGA], peak ground velocity [PGV], significant duration, and pulse period) and the structural seismic response, measured through interstory drift ratio (IDR). Three scenarios are examined to reduce uncertainty in the results: (1) increasing mass eccentricity, (2) enhancing the damping ratio, and (3) reducing the response modification factor ( R I ). Nonlinear time‐history analyses were conducted using a detailed numerical model of 2 six‐story base‐isolated structures limited by surrounding moat walls under pounding and torsion effects. The results demonstrate that PGA is the most dominant earthquake characteristic influencing IDR. Increasing mass eccentricity amplifies the effect of PGA. While increasing the damping ratio strengthens the correlation between PGA and IDR, it weakens the influence of PGV.