| A series of shake table tests of two reinforced concrete bridge column models was conducted. One model is designed to be failed in flexural at the bottom of the column (flexural failure model), and the other is designed to be failed in shear at the cut-off point of the longitudinal reinforcement (shear failure model); both are models of bridge columns that were severely damaged during the 1995 Hyogo-ken Nanbu (Kobe), Japan, earthquake. The models are one-third scaled ones of full-scaled reinforced concrete bridge column models that are planed to be tested on the E-Defense in 2007 and 2008. Failure mechanisms under strong ground excitation and three dimensional dynamic behaviors of these columns were investigated. The flexural failure column was failed around the bottom of the column. Spalling of cover concrete, buckling of longitudinal reinforcement, and crush of core concrete were observed after the test. The shear failure column was eventually failed in shear. The flexural cracks were first observed around the cut-off point of the longitudinal reinforcement, and then shear diagonal cracks developed, resulting in destructive shear failure. Both final failure modes are typical ones observed during the 1995 Kobe earthquake. |
