Tall buildings in Turkey, their characteristic structural features and dynamic behaviour

Since the early twenty-first century, tall building construction has gained significant momentum in the urban cities of Turkey as a result of the population and economic growth. Accruing more than 1500 buildings by year 2015, the majority of the country's exposure now clusters across the seismically active landscape of the Istanbul metropolitan area. As such, the underlying earthquake risk calls for the investigation of the seismic performance of these structures. While hazard studies for Istanbul are available, the literature is still devoid of studies related to the seismic risk assessment of tall buildings located there. As an attempt to fill this gap, this paper focuses on the characterization and quantification of the existing exposure to allow risk assessment both at single building and portfolio levels. To this end, an extensive tall building inventory containing the structural drawings of 94 buildings is compiled and thoroughly examined to make a projection of the design practice. After establishing statistically representative archetypes, we quantified their dynamic response to 1999 Duzce and Kocaeli earthquake ground motions. We notice a maximum difference of 100% in the maximum interstory drift ratios (equaling a 2% increase in absolute value) between two different tall building archetypes. Moreover, the analysis results indicate that the incident angle of the applied ground-motion can be a discriminant factor between structural collapse and survival. The outcome of this study puts forward a robust basis for prospective structural analyses, collapse risk assessment as well as loss estimation analyses of tall buildings in Istanbul.