Assessing the Seismic Collapse Risk of Reinforced Concrete Frame Structures, Including the Effects of Modeling Uncertainties

A primary goal of seismic provisions in building codes and retrofit legislation is to protect life safety through prevention of structural collapse. To evaluate the extent to which these specifications meet this objective, the authors have conducted detailed assessments of the collapse performance of both modern reinforced concrete (RC) special moment frames (SMF) and existing RC non-ductile moment frames. Many aspects of the assessment process, including the treatment of modeling uncertainties, can have a significant impact on the evaluated collapse performance. Approaches for evaluating the effects of modeling uncertainties are described in this study. Uncertainties in strength, stiffness, deformation capacity, and cyclic deterioration are considered for ductile frame structures of varying heights. Due to the computationally intensive nature of these analyses, the effect of these modeling uncertainties is assessed through creation of a response surface from the results of sensitivity analyses. From the response surface, Monte Carlo simulation is used to quantify the impact of these uncertainties on the predicted collapse capacity of each structure. 1