The 14 th World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China BUILDING MONITORING FOR SEISMIC RISK ASSESSMENT (II): INSTRUMENTAL TESTING OF RC FRAME STRUCTURES AND ANALYTICAL REINTERPRETATION OF RESPONSE CHARACTERISTICS M.C. Genes 1 , M. Bikce 2 , S. Kacin 2 , U. Akyuz 3 , P. Gülkan 4 , L. Abrahamczyk 5 , J. Schwarz 6 1 Assistant Professor, Dept. of Civil Engineering, Mustafa Kemal University, Hatay, Turkey Email: mcgenes@mku.edu.tr 2 Assistant Professor, Dept. of Civil Engineering, Mustafa Kemal University, Hatay, Turkey 3 Associate Professor, Structural Mechanics Div., Middle East Technical University, Ankara, Turkey 4 Professor, Dept. of Civil Engineering; Earthquake Eng. Res. Ctr., Middle East Technical University, Ankara, Turkey 5 Research assistant, Earthquake Damage Analysis Center (EDAC), Bauhaus-Universität Weimar, Germany 6 Head of Earthquake Damage Analysis Center (EDAC), Bauhaus-Universität Weimar, Germany ABSTRACT : A joint research program by the Bauhaus-Universität Weimar (Germany), Mustafa Kemal University (Turkey) and Middle East Technical University (Turkey) has been in progress since 2005. The project is concerned with vulnerability and loss estimation studies for the earthquake preparedness of Antakya (current population 200,000), sited on the Dead Sea Fault System in the Eastern Mediterranean, and in close proximity to the East Anatolian Fault System. The ancient town, founded in 300 BC, has been an important confluence of states, faiths and peoples from its earliest times, and has suffered many major earthquakes. The city of Antakya has experienced a rapid population growth during the last 25 years, and many new buildings have been built, generally displaying architectural and structural similarities. Forced vibration tests have been conducted on two eight-storey representative RC frame buildings. The excitation is provided via an eccentric mass vibration generator. Sweeping the frequency of the vibration generator through a range including the natural frequencies of the structure and then recording the steady-state response of the structure at each operated frequency, response resonance curves are obtained. For different locations of each building the acceleration and displacement amplitudes are determined. The experimental data are compared with analytical results from the 3D structural models and a good aggrement is obtained. KEYWORDS: earthquake, forced vibration tests, loss estimation, Antakya region, RC frame buildings 1. INTRODUCTION Knowledge of the behaviour of civil structures under seismic excitation is of great interest in earthquake-prone areas (Lus and Longman, 1999, Benedetti and Gentile, 1994, and Schwarz et al., 2007). For this reason many countries have equipped buildings with continuously monitoring systems in order to record the possible response of the structures during earthquakes. Before the occurrence of an earthquake, it is important to determine the parameters such as natural frequencies and mode shapes related to the dynamic response of the buildings. These parameters can be determined by mathematical models used in the dynamic analyses of structures. These mathematical models are idealizations required to represent the response of real structures to various dynamic loads (e.g. strong eartquake shaking, strong winds, forced vibration, blast etc.). The determination of the necessary parameters for the verification of the models are usually obtained by means of forced or ambient vibration tests (Hudson, 1970, Trifunac and Todorovska, 1999, Beolchini and Vestroni, 1997, and Vestroni et al., 1996). In Turkey, forced vibration testing started in 1976. Earthquake Engineering Research Center of the Middle East Technical University (METU/EERC), started a project to survey the dynamic