Full 3D CAD procedure for the limit analysisi of longhu Pagoda in China

This paper adopts a very convenient 3D CAD method to quickly assess the seismic vulnerability of existing masonry towers. The study selected five typical collapse mechanisms, vertical splitting, base rocking, overturning with diagonal cracks (Heyman 1992), a combination of splitting and diagonal overturning and base sliding. The Longhu pagoda in China is selected as the research case. Based on the principle of virtual works, assuming that the masonry material is a no-tension material, and the collapse acceleration under loads G1 and G2 is calculated from the four main directions. The research results show that vertical splitting of collapse mechanism is the easiest to appear, which is in full compliance with the results of the on-site survey after the Longhu pagoda earthquake, further demonstrating the reliability of this method. This method does not require complex mathematical foundations, can be easily mastered by non-professionals, and at the same time greatly reduces the amount of simulation calculation, which is helpful for the promotion of seismic research of masonry structures