The 14 th World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China COMPARISON BETWEEN REAL TIME NONLINEAR SEISMIC HYBRID AND SHAKE TABLE TESTING TECHNIQUES C.-P. Lamarche 1 , M. Leclerc 2 , R. Tremblay 3 , P. Léger 3 , N. Bouaanani 4 , S. Koboevic 5 , and O. Bursi 6 1 Ph.D. Candidate, 2 Research Associate, 3 Professor, 4 Associate Professor, 5 Assistant Professor, CGM Dept., Ecole Polytechnique, Montreal, QC, Canada Email: charles-philippe.lamarche@polymtl.ca 6 Professor, Dept. of Structural Engineering, Trento University, Trento, Italy ABSTRACT : A direct comparison is made between shake table and real time hybrid simulation testing techniques for a two-storey steel building structure model. Only the first-storey structural components were included in the hybrid test program and a Rosenbrock-W explicit integration scheme was adopted for the numerical solution. The tests were performed under seismic ground motions exhibiting various amplitude levels and frequency contents to develop first and second mode dominated responses as well as elastic and inelastic responses. Excellent correlation was obtained between the two testing techniques, indicating that real time hybrid testing method can be used to successfully reproduce both the linear and nonlinear seismic responses of ductile structural steel seismic force resisting systems. KEYWORDS: Integration scheme, Real time hybrid testing, Rosenbrock, Shake table testing 1. INTRODUCTION As real time hybrid testing becomes more popular among the earthquake engineering community, it is of utmost importance to evaluate the quality of the results obtained from this experimental tool using benchmark testing. The structural engineering testing laboratory of École Polytechnique de Montréal houses a high performance earthquake simulator (shake table) facility which has been in use since 1995. The researchers recently acquired the capability and the technology to perform real time hybrid dynamic testing. In this paper, the results obtained from shake table tests carried out on the two-storey half-scale building structure are compared to real time hybrid testing results. In the hybrid tests, one storey of the structure is tested in the laboratory whilst the remainder is modelled numerically. Time integration is performed using a Rosenbrock-W based methodology. Inelastic response occurs in the form of plastic hinging at the column bases. The shake table test program involved several experiments using different excitation signals including the 1940 El Centro Imperial Valley earthquake record, a high frequency motion typical of Eastern North America (ENA), which occurred during the 1988 Saguenay earthquake, and harmonic signals. The amplitude of the excitations was varied such that both the linear and nonlinear structure responses could be investigated. In the cases where the shake table test structure exhibited a nonlinear response at both storeys, the numerical model used in the hybrid testing also included nonlinear modelling capabilities. This project represents a unique opportunity to compare the two testing techniques as the two test programs were conducted in the same laboratory environment and involved the same physical structural components. 2. SHAKE TABLE TEST PROGRAM 2.1. Test set-up The test structure used in this study is illustrated in Figure 1. It represented a half-scale model of a two-storey steel building. At each level, the structural system consisted of a single cantilevered column rigidly anchored at its base and pin-connected at its upper end. A simplified finite element model of the structure including the