Abstract:The modified form of the Park-Ang damage model for reinforced concrete (RC) structures is put forward with a consideration of the non-convergence of the original model on the upper and lower limit.Then the combination coefficient is calculated on the basis of the cyclic test results of RC columns from the database of the Pacific Earthquake Engineering Research Center (PEER) and the authors’ tests.An empirical formula is derived through nonlinear regression analysis to relate the coefficient with the axial load ratio,shear-span ratio and confinement index provided by the transverse steel.The comparison between the two models indicates that compared with the original model,damage indices at failure state of tests calculated by the modified model have mean value closer to 1 and smaller scatter,and the damage level of RC structures can be better reflected by the modified model.At last,the value of combination coefficient is recommended for ordinary RC members in building structures.
