Vulnerability of Turkish low-rise and mid-rise reinforced concrete frame structures

In this study, seismic safety of low-rise and mid-rise structures, which constitute approximately 75% of the total building stock in Turkey, is investigated by generating fragility curves. The scope is 3, 5, 7, and 9-story reinforced concrete moment resisting frame structures. The uncertainties in material variability and the specific characteristics of construction practice in Turkey are taken into account in the formation of structural simulations. Two-dimensional analytical models are constructed accordingly and categorized as poor, typical, or superior corresponding to the observed seismic performance of structures after major earthquakes in Turkey. The seismic demand statistics in terms of maximum interstory drift ratio are obtained for different sets of ground motion records by performing nonlinear time history analyses. The capacity is determined in terms of limit states and the corresponding fragility curves are obtained from the probability of reaching or exceeding each limit state for different levels of ground shaking. The generated fragility curves are employed in a preliminary evaluation application. For this purpose, Fatih, a highly populated earthquake-prone district in Istanbul, is selected. This study attempts to be a benchmark for future fragility based studies on earthquake damage and loss estimation in urban areas of Turkey.