Probabilistic seismic vulnerability analysis of corroded reinforced concrete frames including spatial variability of pitting corrosion

A probabilistic framework for seismic vulnerability analysis of corroded Reinforced Concrete (RC) frame structures is developed. An advanced nonlinear finite element modelling technique is used to accurately simulate the nonlinear behaviour of prototype corroded RC frames over their service life. Different sources of uncertainties including modelling uncertainties, geometrical uncertainties and spatial variability of pitting corrosion are considered through Monte Carlo simulation and using Latin Hypercube Sampling (LHS) technique. A set of new seismic damage limit states (SDLS) are defined accounting for multiple failure modes of the corrosion damaged frames by means of pushover analyses. The influence of corrosion on nonlinear dynamic behaviour of corroded RC frames is investigated through Incremental Dynamic Analysis (IDA) of proposed frame structures under 44 far-field ground motions. The impact of considering corrosion damaged SDLS, spatial variability of pitting corrosion, and record-to-record variability on seismic vulnerability of RC frames are explored and discussed in detail. It is concluded that disregarding the influence of corrosion on SDLS significantly underestimates the probability of failure of corroded RC frames. The analyses results show that spatial variability of pitting corrosion does not have a significant impact on global nonlinear behaviour and seismic vulnerability/reliability of corroded RC frames.