a study of upgrading methods of masonry buildings without shringing

coustructing masonry building has been done in a large scale in our country. a ccording to the recorded statistics. it comprises the majority of building in our country. the loss of life and property as the result previous earthquakes reveals that masonry building have not functioned properly. meanwhile, their complex behaviors resulted from the heterogenons, nonlinear, and plate behavior of its components has brought about their damages in earthquakes, therefore, ih is assentail to stady these buildings and to persevere the buildings against earthquakes. this paper deals with the assement of the vulnerability of unarmed masonry buildings by the use of building capacity curve representing the resistance. it also concerns eith the way to find mechanical characteristics and shearing resistance curves of strung walls to show the initial step in modeling. the way of constructing a tridimentioal model of these building by using the sap2000 engineering software would be helpful in understanding their behavior in different froms of stringing their nalinear statical analysis and the study of analyzed models can help us understsnt the relative morement of stories, the dagree of ductility and the collapse mechanism in the building. one of the results obtained is that the reduction of the dimensions of horizontal strings would results obtained is that the reduction of the dimensions of horizontal strings would reduce the waste of energy and the ductility in coustruction. when the dimensions of the horizontal and vertrical strings are equal and as thick as the wall strngs, the optimal reative morement and ductility in the buildings are observed. in addition, in buildings with weak and thinner vertical in the strings with the walls and mostly on the frist storg has happened insuch a way that in some models, strings and walls an the secoud story have not collapsed.