Seismic performance of the existing piloti-type masonry structure

The piloti-type masonry structure (PTMS) consists of a concrete frame-shear wall structure in the bottom storey and a masonry structure in the upper storey, which has problems such as large differences in material properties and non-uniform distribution of lateral stiffness. In this paper, two model specimens of the PTMS were designed and fabricated. The effect of the opening on the seismic performance of the PTMS was investigated by the proposed static test and the numerical analysis based on OpenSees. The results revealed that regardless of the presence of openings, the PTMS with specification design requirements has excellent seismic performance. Both the brick masonry structure and the frame-shear wall structure showed satisfactory deformation performance and stable load-carrying capacity. The failure mode of PTMS was related to the storey stiffness ratios (SSRs), and as the SSRs increased the failure gradually shifted to the bottom frame-shear storey, and the openings weakened the overall energy dissipation capacity of the structure and exacerbated the damage of the masonry storey. Numerical analysis revealed that when the opening ratio was less than 30%, the impact on the structural load-carrying capacity was minimal, while when the opening ratio was greater than 50% and the opening aspect ratio was greater than 1, the load-carrying capacity decreased significantly. The irregular arrangement of openings reduced the load-carrying capacity on one side of the structure and led to inefficient material usage or overdesign on the opposite side.