Engineering Structures 25 (2003) 103–114 www.elsevier.com/locate/engstruct Performance of reinforced concrete buildings during the August 17, 1999 Kocaeli, Turkey earthquake, and seismic design and construction practise in Turkey H. Sezen a,* , A.S. Whittaker b , K.J. Elwood a , K.M. Mosalam c a Graduate Student Researcher, Pacific Earthquake Engineering Research Center, University of California, Berkeley, 1301 South 46th Street, Richmond, CA 94804-9471,USA b Associate Professor, Department of Civil, Structural, and Environmental Engineering, 230 Ketter Hall, University at Buffalo, Buffalo, NY 14260, USA c Assistant Professor, Department of Civil and Environmental Engineering, University of California, Berkeley, 733 Davis Hall, Berkeley, CA 94720-1710, USA Received 26 March 2002; received in revised form 17 July 2002; accepted 17 July 2002 Abstract A large number of reinforced concrete buildings collapsed or were heavily damaged during the 7.4 magnitude earthquake that struck northwestern Turkey on August 17, 1999. Recorded peak ground accelerations were relatively low (0.3 g–0.4 g) compared to the magnitude of the structural damage, and the elastic acceleration response spectra from the recorded motions were comparable with the elastic design spectra specified in the current Turkish seismic code. Seismic code requirements are discussed and compared with observed details. Many structural deficiencies were highlighted by the earthquake damage, including: reinforced concrete columns with insufficient confinement and transverse reinforcement, 90-degree hooks at the end of column ties, poor detailing in beam-column joint regions, strong-beam and weak-columns, soft and weak stories, and poor quality construction. Buildings with shear wall structural elements generally performed well.  2002 Elsevier Science Ltd. All rights reserved. Keywords: 1999 Turkey earthquake; Earthquake damage; Reinforced concrete; Seismic behavior; Codes; Design 1. Introduction On August 17, 1999, a M w 7.4 earthquake occurred on the 1500-km-long North Anatolian fault in northwest- ern Turkey. The epicenter of the earthquake was near Izmit, 90 km east of Istanbul (Fig. 1). Following the earthquake, the Pacific Earthquake Engineering Research Center dispatched a reconnaissance team to the epicentral region to learn first hand about the perform- ance of the civil infrastructure. The geographic region that was impacted by the earthquake was somewhat nar- row banded and centered around the fault, and stretched from Istanbul in the west to Go ¨lyaka and Du ¨zce in the east. Damage to building construction was severe and * Corresponding author. Tel.: (510) 231-9510; fax: (510) 231-9471. E-mail address: sezen@ce.berkeley.edu (H. Sezen). 0141-0296/03/$ - see front matter  2002 Elsevier Science Ltd. All rights reserved. PII:S0141-0296(02)00121-9 Fig. 1. Map of affected region showing recorded peak ground accel- erations in circles (as percentage of acceleration of gravity). widespread (Sezen et al. [1], Aschheim [2], Scawthorn [3]). Estimates for economic losses were around 20 billion US dollars. The official death toll was over 17,200, with some 44,000 people injured and thousands