Identification of failure mechanisms in existing unreinforced masonry buildings in rural areas after April 4, 2019 earthquake in Turkey

Many unreinforced masonry buildings are completely destroyed after destructive earthquakes but, their failure mechanisms cannot be precisely determined. More specifically damage to such buildings is evinced during low or moderate magnitude earthquakes. The aim of this study is to identify the failure mechanisms of existing unreinforced masonry buildings and present a reconstruction strategy or offer strengthening procedures, in order to inhibit damage to masonry structures after destructive earthquakes. For this purpose, a moderate magnitude earthquake which occurred on April 4, 2019 near the township of Sivrice in Elazığ city, in the east of Turkey, was investigated. The magnitude of the studied seismic motion was expressed as Mw=5.2 by the Ministry of Interior Disaster and Emergency Management Presidency. Although this seismic effect was a moderate magnitude earthquake, significant failures occurred. Many masonry buildings and adobe dwellings in the villages of Sivrice were severely damaged by the earthquake. For field observations, ten villages located around the epicentre were visited 65 dwellings were observed and the damage patterns were assessed in detail. The observations showed that the main reasons for the damage to the dwellings were weak structural detailing of wall-to-wall and wall-to-roof connections, inhesion of earthen roofs, and a lack of bond beams in the structural walls. According to field observations, it is deduced that the performance of the undamaged masonry dwellings after earthquakes does not prove that they have adequate seismic safety. Therefore, reinforcing methods (shotcrete implementation, decreasing of space, corner reinforcing etc.) and innovative strengthening procedures (fibre reinforced polymer) are recommended for the undamaged existing unreinforced buildings at the end of the paper.