A Proposed Damage Model for RC Bridge Columns under Cyclic Loading

Abstract

This paper defines a damage index based on the predicted hysteretic behavior of a concrete column. The model yields a damage index at a point in the time history for the element, based on the predicted monotonic response from the point in time to failure. The model takes into account the parameters that describe the hysteretic behavior: stiffness degradation, strength deterioration, and ultimate displacement reduction. Therefore, the damage model is accumulative and it combines energy, ductility, and low-cycle fatigue. The model is based on the work needed to fail a reinforced concrete column monotonically after it experiences a cyclic loading. The model modifies the ultimate displacement that the column can achieve, due to low-cycle fatigue in the longitudinal reinforcement using the Coffin-Manson rule in combination with Miner's hypothesis. The proposed model is applied to bridge columns tested by others, and compared to existing damage indices. The proposed model gives a realistic prediction of damage throughout the loading cycles for several test specimens investigated.