A MODIFIED PARK-ANG SEISMIC DAMAGE MODEL CONSIDERING THE LOAD PATH EFFECTS

Reasonably evaluating the damage of structures and components under earthquake action is an important subject in earthquake engineering research field. Because of the good experimental foundation as well as approximately considering the comprehensive function of first passage and cumulative damage effect, the Park-Ang seismic damage model has been widely used since it was proposed. However, it cannot consider the load path effects and the damage index will become greater than unity under monotonic loading. After analyzing the experimental results published previously, a modified model is proposed based on low-cycle fatigue theory and Miner’s rule. Then the modified model is verified by the experimental results of Kunnath. The results show that the modified model can accurately evaluate the low-cycle fatigue damage under small displacement loading. Furthermore, it also can improve the accuracy of damage evaluation, as it reduced the coefficient of variation of the damage index when the failure is caused by different load paths.