Simplified Mechanics-Based Approach for the Seismic Assessment of Corroded Reinforced Concrete Structures

Abstract

The durability of older reinforced concrete structures is significantly affected by corrosion of the steel reinforcing bars, and assessing the seismic capacity of such corroded RC structures is a challenging task. A simplified mechanics-based assessment procedure was developed to account for the effect of corrosion on the residual strength and displacement capacity of corroded RC members. The procedure was verified against a large database of experimental results from the available literature. A case study of a severely corroded RC building in New Zealand, constructed in 1928, was assessed using the proposed methodology. Although no change in failure mechanism was found, the overall displacement capacity of the building was 25% lower than the assessed uncorroded condition. Long-term corrosion effects were investigated for the case study building assuming no remediation of corroded reinforcing bars. It was found that the displacement capacity would be significantly reduced via the formation of story collapse at less than 1% drift after 30 years of continued corrosion deterioration if no remediation was made.