PROBABILISTIC ANALYSIS OF FLEXURAL OVERSTRENGTH FACTOR FOR SEISMICALLY DESIGNED REINFORCED CONCRETE BEAMS AND COLUMNS

Abstract

The study presented here aims to address some issues related to seismic design of structures, with special focus on the probabilistic modeling of reinforced concrete (RC) cross-sections capacity. It aims to validate the overstrength factors provided in Eurocode 8 for the design RC beams and columns. A statistical analysis is carried out to determine the uncertainty in the reinforcing steel properties. Uncertainties in concrete properties, geometry of cross-sections and mechanical model are also considered. Assessing the flexural overstrength of RC beams and columns designed according to Eurocode 8 involves ensuring that the structural members meet the capacity design specifications. This research studied 128 cross-sections of beams and columns with different geometry and reinforcement areas by performing Monte Carlo simulation. The code provisions are evaluated through a comparison with the simulation results. In particular, the analyses suggest using an overstrength factor of 1.5 for beams and columns with 95% probability of exceedance (or 1.3 with 50% probability of exceedance). Eurocode 8 provisions, adopting an overstrength factor of 1.3, does not seem conservative enough.