Analysis of the composite mechanical properties of the substructure of a masonry pagoda

Brick wall tubes, a popular form of ancient masonry pagoda, can be seen as a spatial lateral force resistance system. The masonry of the ancient pagoda is a case of compression and shear developed due to earthquakes. This composite compression and shear behavior is one of the key issues in the seismic capacity of masonry tube structure. In order to study the mechanical properties of the substructure of masonry pagodas, three sub-structural models were designed and constructed. Low cyclic loadings tests were conducted on the models and the crack, deformation, and failure phenomena were surveyed during the loading process. Simulation models were then developed for calculation, and results were obtained about the equivalent strain and load-displacement curve. Comparing the calculated results with the experimental results, the effects of vertical compressive stress on the masonry in the ancient tower were analyzed. Results showed that the error was less than 21% for the calculated value of the characteristic load relative to the test value. The distribution of equivalent plastic strain was consistent with the crack failure area of the specimens. When the vertical pressure remained constant with increasing horizontal load, the tower body gradually cracked, damage occurred along the masonry joints, and the width of cracks also increased. The failures around the structure opening were more obvious, and the residual deformation of specimens increased. With the increase in the ratio of compression to shear, the range of cracking and damage to the masonry of the ancient tower decreased, while shear bearing capacity, stiffness, and energy dissipation capacity were increased. However, ductility and deformation capacity slightly decreased. These results can provide references for the assessment to structural damage and seismic capability of ancient masonry pagodas.