a. jahanmohammadi

Regarding the decisions made in the 41st world heritage committee for the nomination of historic city of Yazd, Iran has to maintain the buildings located in the core and buffer zone of historic district of the city and construct new buildings as well. With respect to new buildings, natural and cultural issues must be considered and architectural details must be followed in compatible with district’s specifications. In addition, new methods must be adopted to improve the behavior of the buildings; the methods must be compatible with the structural essence. Based on the reports, most of the buildings located in the historic core and buffer zone of Yazd are typically one- or two-story adobe masonry buildings, especially ancient, traditional or historic ones. Therefore, for constructing new buildings, using adobe as the main material is required. This will result in investigating the properties of adobe as the material, adobe masonry building for detecting the load-bearing system and the constructional features that may help the whole response of the building to the earthquake forces. In this regard and with respect to the architectural aspects of historic buildings in a historic district, the structural performance in response to imposed forces is evaluated and participation of adobe walls in bearing the vertical and horizontal forces is determined. Based on the existing information resulted from the evaluation of characteristics of adobe, the main specifications of adobe as the main material in before mentioned construction is presented. These results are mainly focused on the adobe units made in Yazd and by using the soil of the district. Using this information, the common expected values for compressive, tensile and flexural strength of adobe units and clay mortar are presented. To evaluate the performance of adobe walls which are built in a historic building with natural material and by experts, previous investigations are reviewed. These investigations usually cover the experiments on adobe units and adobe prisms made by natural materials of Yazd city. To complete the overall investigation in this regard, complementary tests are followed in this research. Specimens of the test have been prepared by using the adobe units and clay mortars made in the city of Yazd. The preliminary tests have been conducted on the adobe units, clay mortars and adobe prisms. After that, performance of a full-scale adobe wall under the simultaneous horizontal and vertical loads is evaluated. Regarding the results, behavior of an unreinforced adobe wall is detected and its defeats are reported. Based on the experimental results and previous studies performed on studying the architectural features of the historic district of Yazd, recommendations for common values of the strength in adobe units and prisms are presented. In addition, special issues are raised. These issues must be considered in constructing the adobe masonry buildings in order to fulfill the architectural requirements and help the whole structure to bear the gravity and seismic forces. It is expected that these issues be considered in any upcoming guidelines that will be provided for constructing new adobe buildings in Yazd and any other historic districts.