Numerical model for biaxial earthquake response of reinforced concrete

A numerical constitutive model is developed to simulate the biaxial nonlinear flexural response of slender reinforced concrete members subjected to earthquake excitation. The model is tested using data from two types of experiments with reinforced concrete elements: (1) elements subjected to varying pseudo-static biaxial lateral loads and (2) elements that responded biaxially to simulated earthquake motions. The goal for the model was not only to help determine the absolute maxima for earthquake response but also to enable calculation of the entire waveform, including the ranges of low- and moderate-amplitude response. The comparisons of measured and calculated results and sensitivity of the proposed model to variations in the input parameters are discussed. The output was found to be insensitive to the changes in input parameters related to concrete and sensitive to input parameters related to reinforcing steel. The results of the calculations were tested using experimental data.