COLLAPSE SIMULATION OF REINFORCED CONCRETE BUILDINGS WITH ASFI APPROACH

We have carried out full-scale shaking tests on three-story reinforced concrete school buildings, one RC frame and the other strengthened, at E-Defense in 2006. A dynamic progressive collapse occurred associated with shear and axial failure of short columns in the RC frame specimen with fixed bases under an extreme level of earthquake motion. A method of simulating the collapse behavior of the specimen was developed with columns members, in which shear deteriorating behavior after flexural yielding was incorporated. The axial and lateral hysteretic responses of the inner column were measured at the column base in the dynamic test, which was compared with the analytical result to verify the analytical model. Nonlinear earthquake response analysis was carried out with three-dimensional frame model, taking account of shear deterioration of the columns. The effects of shear deterioration in the columns as well as the intensity and duration of the earthquake motion were discussed based on various cases of collapse simulations. Introduction It is necessary for collapse simulation of existing reinforced structures in Japan to estimate the ultimate deformation capacity of brittle short columns. However, The accuracy of the estimation is not adequate, because the deformation capacity depends on confinement, shear span ratio, axial stress, and material property. Japanese seismic evaluation standard for existing structures roughly estimates the deformation capacity of columns based on the ratio of shear strength to flexural strength, which is empirical and conservative lower bound of the test results. We have carried out the full-scale shaking tests on two three-story reinforced concrete buildings with flexible or fixed foundation from September to November 2006 at E-Defense, the world largest three-dimensional earthquake simulator, as a part of a five-year national project on seismic safety of urban areas, referred to as DaiDaiToku project (Toshimi Kabeyasawa, 2006 and Toshikazu Kabeyasawa, 2006). One of the purposes in the shaking test on the first RC Project Research Associate, Center for Sustainable Urban Regeneration, School of Engineering, University of Tokyo, 7-3-1 Hongou, Bunkyo-ku, Tokyo, Japan Professor, Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan Research Associate, Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan Proceedings of the 9th U.S. National and 10th Canadian Conference on Earthquake Engineering Compte Rendu de la 9ième Conférence Nationale Américaine et 10ième Conférence Canadienne de Génie Parasismique July 25-29, 2010, Toronto, Ontario, Canada • Paper No 816