SEISMIC DEMAND ESTIMATES OF MID-RISE RC BUILDING SUBJECTED TO CODE COMPLIANT EARTHQUAKE RECORDS Esra OZER 1 , Muhammet KAMAL 2 , Bayram Tanik CAYCI 3 Mehmet INEL 4 ABSTRACT This study aims to compare displacement demands of mid-rise reinforced concrete buildings for the scaled ground motion records compatible with design spectrum of the draft Turkish Building Earthquake Code for the ZC soil type using the 2D building models. The estimates of 2D models are also compared to the estimates obtained by the 3D models to evaluate the performance of 2D models. Two structures selected as 10 and 15 stories were considered to represent the mid-rise reinforced concrete buildings in the scope of the study. The 2D models were derived from the inner axes of 3D models in two principal directions. 11 records from past earthquakes were selected and scaled to be compatible with spectrum in the draft Turkish Building Earthquake Code-2016. A total of 88 dynamic analyses were performed with 11 different records taking into account the two principal directions of 10- and 15-story buildings for the 2D and 3D models. The outcomes show that the average interstory drift ratio does not exceed the 2% code limit although the demands exceeded this limit for several records. The comparison of 2D and 3D model estimates clearly indicate that the proper 2D representation of 3D building models are important. The selection of inner axis as being common practice may not always represent the 3D models properly. The differences in period or lateral strength capacity of 2D and 3D models may cause incorrect displacement demand estimates when the 2D models are used. Keywords: Nonlinear behavior; two-dimensional frame models; nonlinear time-history analysis; elastic design spectrum; scaled ground motions 1. INTRODUCTION Many earthquakes occurred in the past caused remarkable number of casualties and significant damage of properties. Seismic demand estimates are essential for seismic performance evaluation of existing buildings. Nonlinear time history analysis provides the most realistic demand estimates especially by using scaled and selected code-compatible earthquake records. This study aims to compare displacement demands of mid-rise reinforced concrete buildings for the scaled ground motion records compatible with design spectrum of the draft Turkish Building Earthquake Code for the ZC soil type using the 2D building models. The estimates of 2D models are also compared to the estimates obtained by the 3D models to evaluate the performance of 2D models. The study shows that although the displacement demand estimates have a wide scatter, the mean estimates of the considered buildings range in a very narrow band. Different scaling methods such as frequency-domain or time-domain method can be used. Time- domain method only changes the magnitude of the record by preserving the basic seismological features of the records. Thus, time domain method was used in this study. The principles for the selection and scaling of earthquake ground motion records are also included in the literature (Hachem et al. 2010, Ergun and Ates 2013). In this study, 11 real earthquake records selected from PEER ground motion database were scaled to 1 Research Assistant, Pamukkale University Civil Engineering Department, Denizli, Turkey, esrao@pau.edu.tr 2 Research Assistant, Pamukkale University Civil Engineering Department, Denizli, Turkey, mkamal@pau.edu.tr 3 Asst. Professor Dr., Pamukkale University Civil Engineering Department, Denizli, Turkey, bcayci@pau.edu.tr 4 Professor. Dr., Pamukkale University Civil Engineering Department, Denizli, Turkey, minel@pau.edu.tr