From worldwide observations made after the occurrence of earthquakes, as well as the tremendous amount of experimental, analytical and numerical studies, significant contributions have been made for a better understanding of the characteristics of earthquakes, and effects of earthquakes on existing structural systems. Consequently, seismic design codes are revised in a parallel fashion by integrating new concepts towards more realistic considerations of seismic demand, seismic response and seismic capacity. In this paper, after outlining the performance of existing buildings in Turkey during recent earthquakes (particularly Kocaeli 1999 and Duzce 1999 Earthquakes), and by focusing on the observed common structural deficiencies, a brief summary of the evolution of the Turkish Seismic Design Code in the last decades is presented. It is important to note that the poor seismic performance of existing buildings in Turkey outlined in this study is not directly related to the inefficiency of the relevant seismic design codes, but rather to extremely low quality construction and the absence of a strict inspection system at the time of their construction. It should also be highlighted that the lessons learnt from the catastrophic consequences of recent earthquakes, revisions in the seismic design code and the developments in the material and workmanship characteristics have significantly improved the quality of newer constructions in Turkey in the last decade.
