Kukrit Toongoenthong and Koichi Maekawa Journal of Advanced Concrete Technology, 3(1) 107-122, 2005 For explicitly taking into account corrosion cracks in structural safety performances, a multi-mechanical model is presented to deal with materialized corrosive substances around steel bars and equilibrated damage in structural concrete. The multi-mechanics of corrosive product and cracked concrete are integrated with a nonlinear multi-directional fixed crack modeling so that corrosion cracks in structural concrete can be simulated in a unified manner. Structural analysis of corroded RC beams is carried out for experimental verification of the multi-mechanical model in terms of shear capacity and ductility. RC beams, which primarily fail in shear or flexure, are discussed and special attention is addressed to conversion of failure modes and the absolute capacity. Consideration of inherent cracking on corroded RC members is proven to be crucial for structural performance assessment and the anchorage failure of longitudinal reinforcement is found to cause considerable decay of member capacity.

New ideas in assessing cracks in concrete members by the corroosion rates and in evaluating the structural performance by the steel corrosion were systematically introduced in an analytical manner. Conventional research has dealt with the degradation of flexural stuructural performance solely by the loss of steel cross-sectional area during corrosion, while this paper showed, both by analyis and experiment, that the fracture modes become defferent and shear structural performance is also influenced by the location of corrosion. (Prof. Ishida, The University of Tokyo)