Axial-Bending Interaction Diagrams of Reinforced Concrete Columns Exposed to Chloride Attack

Abstract

This paper focuses on reinforced concrete columns load carrying capacity degradation over time due to chloride induced steel pitting corrosion. The structural element is exposed to marine environment and the effects of corrosion are described by the time degradation of the axial-bending interaction diagram. Because chlorides ingress and consequent pitting corrosion propagation are both time-dependent mechanisms, the study adopts a time-variant predictive approach to evaluate residual strength of corroded reinforced concrete columns at different lifetimes. Corrosion initiation and propagation process is modelled by taking into account all the parameters, such as external environmental conditions, concrete mix proportion, concrete cover and so on, which influence the time evolution of the corrosion phenomenon and its effects on the residual strength of RC columns.

The Effect of Shape on Chloride Penetration of Circular Reinforcement Concrete Columns and Its Durability Design

“…As the concrete servicing age increases for the situation neglecting the effect of the surrounding, D is expressed as follows [23]:…”

“…where C(x,t) represents the chloride concentration at distance x from the external surface at time t, R denotes the radius of the RC circular column, J 1 is Bessel's first function with order one, and α m depends on the solution of J 0 (Rα m ) = 0. Assuming that the circular section is oversimplified as a slab element directly, the corresponding slab diffusion model is given as [23]:…”