Discrete element analysis of dynamic characteristics and earthquake collapse of solid structure ancient masonry pagoda

Abstract

In order to investigate the seismic damage and collapse mechanism of ancient masonry pagodas, a numerical model of the Tang Dynasty masonry pagoda (Xuanzang Pagoda) located at Xingjiao Temple was established using the discrete element software 3DEC, and non-linear mechanical parameters of the contact surfaces between rigid blocks were defined. Dynamic characteristics were analyzed, and the seismic response of the ancient pagoda was calculated by inputting El-Centro waves, Tianjin waves, and Lanzhou artificial waves with different intensities in three directions. The study analyzed the damage failure process of the pagoda, identified vulnerable areas, and obtained its collapse.The results show that the ancient pagoda behaves as an elastic–plastic system at intensity 7 degree seismic action. The acceleration response of the floors increases along the height, and the displacement angle between floors appears as an inflection point at the second floor. The middle floors are especially vulnerable to damage due to low cohesion and strong movements of the internal soil fill. As the intensity increases, significant damage occurs, with rapid floor displacement response and upward extension of cracks. The top floor of the ancient pagoda collapses first with stair-shaped oblique cracks, followed by a floor-by-floor destruction from top to bottom. The collapse of floors with different hole locations also vary. These findings provide valuable insights for predicting the vulnerable areas and collapse of Xuanzang Pagoda under seismic action.