Seismic Performance Assessment of Confined Masonry Buildings Based on Displacement

Confined masonry buildings exist or are constructed in some countries due to low cost, simplicity of construction, easy access to materials, and no need for a professional workman. Experience from past earthquakes shows that poor quality of construction and nominal designs are some reasons for the seismic vulnerability of this kind of structure. One of the nominal values in the codes for the design of masonry buildings is the density of masonry walls or the ratio of the area of walls to the area of the plan regardless of the structural features. In this study using the existing constitutive behavior of confined masonry walls and nonlinear static analysis in the form of Acceleration-Displacement Response Spectra (ADRS), the various plans with different densities of walls as prototypes models are assessed for design spectrum presented in standard No. 2800 with a return period of 475 years. For this purpose, the maximum drift of walls at the performance-point of models is compared with various limit states. The results show that based on the value of wall density the seismic behavior of models varies from linear to nonlinear response and the determination of density of walls in the confined masonry buildings for each limit state depends on the characteristics of the wall and several stories. This method could be recommended for the performance-based design of confined masonry buildings.