Seismic Consolidation of Rural Adobe Building (Case Study: Tabas Isfahak Historical Village)

After the earthquake of Tabas at 19:36 pm in September 16, 1978, a large part of the buildings were destroyed and there were many human casualties. With more research, it can be seen that a significant number of these damages and losses from the earthquake had been related to rural buildings around the city (Tabas). Due to the fact that the Tabas area has a warm, dry and desert climate, Villages that suffered such damages were mostly mud and adobe structures. One of these villages is Isfahak (located 38 km south-east of Tabas city) that based on available evidence has a historical background from the Safavid period, As an example of the rural adobe fabric in the Tabas area, it suffered damage and destruction in various dimensions of its physical fabric during the earthquake. According to local information, about 80 people of inhabitants died due to this natural occurrence, and a few others suffered physical and psychological damages. This adobe fabric has been registered as an interesting example of Iran's climatic technology and traditions in relation to rural housing. The use of traditional and local materials in Iranian architecture is now listed in the National Iranian monuments List No. 31336, and in recent years, with the tendency of local people, and especially the desire of educated young people to stay and reside, brings potential opportunity for tourism to growth. The heritage value of the village of Isfahak along with its physical and cultural-social values and the aspect of reminding a historical event (Tabas earthquake as one of the largest and most deadliest earthquakes in Iran) affecting the lives of the people of this region, has created a collection of various values and potentials that need to be protected and rehabilitated. On the other hand, considering the probability of the occurrence of an earthquake and its related financial and death threats for rural adobe buildings is needed to research for raising the level of safety and seismic function in such buildings. Therefore, this study after investigating the most important structural weaknesses of damaged adobe buildings due to the effect of this earthquake and categorization of the seismic damages, then how to strengthen the adobe buildings of Isfahak village. The research method is descriptive-analytical and the data collection had been done via the means of literature review and field observation. By studying similar and successful previous experiments and researches on how to improve seismic performance of adobe buildings and considering different aspects of the problem during frequent field visits from the earthquake site located in Isfahak, in relation to seismic consolidation of these buildings, were proposed three designs: A, B and C. The designs were evaluated and compared in terms of theoretical principles of architectural heritage restoration and seismic function validation by modeling in the ANSYS software. Finally, the design of B (the application of wooden elements and woven ropes from palm fiber to integrate structural behavior of building components) due to the most consistency with the policies and strategies defined in relation to how to perform the intervention as an optimal seismic consolidation model for adobe buildings of Isfahak village were proposed. In fact, the project has been performed through seismic authentication and is more consistent with the theoretical principles of restoration. In addition to the economic feasibility and ease of implementation as two important criteria for attracting local people's participation, more than two other projects are considered in this plan.