Energy Dissipation Capacity of Reinforced Concrete Columns under Cyclic Displacements

Abstract

This study investigates the energy dissipation characteristics of reinforced concrete columns under inelastic cyclic displacements. Twenty column specimens were tested under constant-amplitude displacement cycles and three column specimens were tested under variable-amplitude displacement cycles. The effect of failure mode, displacement ductility, material properties, and detailing on the energy dissipation capacity of columns is investigated under constant-amplitude loading. The authors develop a simple model for predicting the cyclic energy dissipation capacity under constant-amplitude inelastic displacement cycles. An analytical procedure then is introduced for calculating the energy dissipation under variable-amplitude displacement cycles by using the energy dissipation capacity obtained under constant-amplitude displacements. The variation of effective damping with the number of cycles is also investigated. The results show that the cyclic energy dissipation capacities of all types of columns deteriorated with the number of cycles under constant-amplitude displacement cycles. The normalized energy dissipation capacities of well-confined columns in flexure-shear mode are similar to those of the well-confined flexural column specimens. By using dissipated energy as a memory agent, the prediction of cyclic energy dissipation can help improve hysteresis models.