Seismic Collapse-Resistant Performance of Stone Houses in Tibetan and Qiang Autonomous Prefectures of Western Sichuan

Traditional stone houses in the Tibetan and Qiang autonomous prefectures of Western Sichuan, deserve preservation as indicators of cultural heritage; however many of them have been damaged during earthquakes in recent years. Based on the characteristics of masonry materials and architectural layout, seismic collapse-resistant performance of stone houses was investigated. Unconfined compression tests on three clay specimens and lateral shear tests on a half-scaled clay-brick rubble masonry wall specimen were conducted and also modeled via an explicit dynamic numerical approach. The Holmquist–Johnson–Cook (HJC) constitutive model was applied to the clay and rubble, and a randomly-distributed discrete finite element model was built to show the proportion between clay and brick rubble. Through the comparison of experimental and numerical results, the numerical model was verified and key parameters were calibrated. According to above work, a structural model of a typical two-storey residential stone house with an L-shaped indented platform was built, and its dynamic time-history analysis was conducted. By comparing the calculated seismic damage modes with its real seismic damage, the collapse mechanism was analyzed and the collapse process was simulated. Moreover, the structural fragility of seismic collapse was studied based on the influence of the indented area of the platform. The results indicate that, under rare seismic intensity, when the indented area is increased from 30% to 45%, the probability of structural collapse increases by 16.7%, and the collapse margin ratio decreases by 9%, which has little effect on the fragility curve. However, when the indented area is reduced to 15%, the failure rate of walls on the second floor increases by 18%, leading to the increase of 143% in the probability of structural collapse.