Abstract

Public buildings which are mostly built of reinforced concrete with template designs constitute a great part of the vulnerable public building stock in Turkey as well as in several other countries prone to earthquakes. This study focuses on seismic fragility assessment of reinforced concrete public buildings with representative template designs, which have been designed according to the 1975 version of the Turkish seismic design code. Lateral stiffness, strength and displacement capacities of the selected template designs are determined by nonlinear static analyses in two principal directions. The inelastic dynamic characteristics of the template designs investigated are represented by equivalent single degree of freedom systems and their seismic deformation demands are calculated using a set of 100 strong ground motion records. Peak ground velocity is selected as the measure of seismic intensity because it has a good correlation with maximum inelastic displacements. Based on assessed capacities and demands, fragility curves are derived separately for each template designs. Buildings are grouped according to the number of storeys. The results revealed that the effect of concrete and detailing quality on IO performance level is more limited and less critical as the ground motion intensity increases. On the other hand, the probability of exceedence for LS and CP are closer to each other for each group of buildings. Finally, using constructed fragility curves, collapse probabilities of existing public buildings were estimated according to PGV values. The results are evaluated in terms of concrete quality and transverse reinforcement detailing.