Estimation of constant-damage residual displacements in terms of maximum inelastic displacements for SDOF structures.

This paper investigates the constant-damage residual displacement ratios C_r (i.e., the ratio of the residual displacement in terms of the maximum inelastic displacement) of single-degree-of-freedom (SDOF) systems with different damage levels. A statistical study aimed at estimating the constant-damage C_r is conducted using the modified Park–Ang damage model when subjected to 228 ground motions recorded in California and organized for the NEHRP soil type, peak ground acceleration and ground motion duration. The effects of soil type, damage model and hysteretic behaviour are highlighted. The results indicate that constant-damage C_r increases when the damage index increases, reaching a limit at a damage index of 0.5. An empirical expression is finally proposed with two-step regression analysis to provide a reliable estimate of constant-damage C_r for SDOF structures. [ABSTRACT FROM AUTHOR]