Ground Motion Duration Effects on Hysteretic Behavior of Reinforced Concrete Bridge Columns

AbstractThis study examined seismic behavior under long-duration ground motion in flexural-dominated reinforced concrete bridge columns designed per modern seismic design codes. Two column specimens with identical design parameters were tested. The first column (named CLC) was tested using a long-duration loading protocol developed to represent the number of response cycles expected under long-duration ground motions. The second column (named COC) was tested using a baseline loading protocol with one cycle for each drift loading to obtain baseline behavior for comparison with the behavior of the CLC column. Test results showed that the CLC column had a similar peak strength but a lower ductility capacity compared with the COC column. When drift was 3% or less, the columns showed a similar hysteretic envelop response. However, degradation of stiffness was greater in the CLC column. When drift exceeded 3%, the CLC column started to show greater strength degradation. The relationship between the damage index...