Document Type : Review Article
Department of Civil Engineering, Islamshahr Branch, Islamic AZAD University, Islamshahr, Iran.
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 of seismic vulnerability of this kind of structures. One of the nominal values in the codes for the design of masonry buildings is density of masonry walls or the ratio of area of walls to area of plan regardless of the structural features. In this study using 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 density of walls as prototypes models are assessed for design spectrum presented in the standard No. 2800 with 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 vary from linear to nonlinear response and determination of density of walls in the confined masonry buildings for each limit state depends on the walls characteristics and number of stories. This method could be recommended for performance- based design of confined masonry buildings.