Full 3d Cad Procedure for the Limit Analysis of Zhongjiang South 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 (according to Heyman's approach on tilting towers), a combination of splitting and diagonal overturning and base sliding. The Zhongjiang South pagoda in China is selected as the research case. Basing on the principle of virtual works, assuming that masonry behaves as a small cohesion and frictional material, the collapse acceleration is calculated with a direct manual procedure. The research results show that vertical splitting is the easiest collapse mechanism to appear, which is in full compliance with the results of the on-site survey carried out after the Zhongjiang earthquake, further demonstrating the reliability of this method. Such approach does not require complex mathematical foundations, can be easily mastered by non-professionals, and at the same time greatly reduces the amount of simulations/calculations, a feature which is helpful for the promotion of seismic research of masonry structures.