Appropriate Models for Practical Nonlinear Dynamic Analysis of Reinforced Concrete Frames

ABSTRACT: The object of this paper is to identify the optimal combination of hysteresis-model and damping parameters that lead to the best correlation between the calculated and measured seismic response. The combined effects of five parameters are investigated: initial stiffness, bond-slip deformations, post-yield stiffness, unloading stiffness, and type of damping. The first four of these parameters are implemented using the Takeda hysteresis model to characterize the moment-rotation dynamic response of individual frame members. The analyses use lumpedplasticity models concentrated at member ends. The study uses the recorded seismic responses of two ten-story laboratory structures and two orthogonal structural systems in an existing seven-story building. For each case of analysis, the calculated roof displacement history is compared to the measured response by means of the frequency domain error index (FDE), facilitating the identification of the combination of parameters that leads to the best analytical simulation. Although the best simulations are attained in models with uncracked initial stiffness, hard post-yield stiffness, and reducing unloading stiffness, models with cracked initial stiffness that lead to satisfactory simulations are also identified.