Corrosion-induced moment redistributions of RC frame structures under service loads

This paper presented the corrosion-induced moment redistributions in RC structures under service loads. To do so, the flexural stiffness calculation formulas were proposed for corroded RC beams and columns. Then, RC beam tests were designed and conducted, which, as combined with several RC column tests collected from the literature, were used to validate the proposed formulas. The comparison between calculated and experimental results showed that the accuracy of the proposed flexural stiffness calculation formulas was acceptable. After that, an RC frame under vertical and lateral loads were designed to show the effects of corrosion on the moment redistributions. It was found that corrosion of steel bars at different sides of an RC component could lead to different reductions of the bending stiffness of the RC component around different axes. Moreover, corrosioninduced bending stiffness reductions were different among different RC components in an RC frame, which further caused moment redistributions among different components. In addition, corrosion-induced moment redistributions could increase or decrease the moments on the RC components and these moment changes were not necessarily monotonous as corrosion propagated. These findings informed civil engineers that both the internal force changes and bearing capacity reductions should be considered simultaneously and elastic analyses based on the flexural stiffness calculation formulas could be conducted to quickly evaluate the safety of an existing corroded RC structure under service loads.