The Assessment of the Influence of Soil Type on the Nonlinear Seismic Response of a Corroded Reinforced Concrete Portal Frame

Abstract

Background: Most researchers have focused on the effect of rebar corrosion on the seismic behaviour of reinforced concrete (RC) columns. On the other hand, the influence of chloride corrosion of reinforced concrete in combination with soil type on the seismic behaviour of RC columns has not been investigated. Objective: This paper investigates the influence of soil characteristics on the seismic vulnerability of reinforced concrete structures. The case study in focus is a reinforced concrete portal frame with columns exhibiting corrosion at ground level. Methods: Chloride ingress initiates corrosion and reduces the cross-sectional area of the corroded concrete steel. In addition, this research considers two different soil types, namely rocky and loose, as relevant factors in the analysis. Firstly, the seismic loads are determined according to the Moroccan seismic building code RPS2011. Then, the evaluation of the evolution of the diameter of corroded bars due to chloride induced corrosion is investigated. Finally, pushover analysis is used to determine the location of the performance point on the capacity curve. Results: The study also includes an investigation of the ductility characteristics of corroded reinforced concrete structures and the inter-storey displacement in different soil conditions. The results show that the inter-storey displacement decreases with increasing age of the structure. In addition, it is observed that the base shear force and roof displacement at the point of failure are more sensitive in loose soils compared to rocky soils. Conclusion: The results indicate that consideration of soil type can significantly alter the expected seismic performance, resulting in higher vulnerability values.