Nonlinear Analysis of a R.C. grillage deck exposed to corrosion

In this paper, an approach consisting in the analysis of the diffusion of the deterioration processes induced by aggressive agents, followed by the analysis of the damaged structure is presented. The damage process, induced by chloride diffusion, is modelled through a Cellular Automata algorithm. The structural analysis is based on R.C. spatial beam element, dealing with both mechanical and geometrical nonlinearities. The proposed method is applied to studying the structural response, both at the serviceability and ultimate limit states, of a damaged, 50-years-old R.C. grillage deck exhibiting a severe corrosion state. The analyses show how damage effects at a given time reduce the overall bearing capacity of the deck and how the internal forces redistribute from damaged to undamaged structural parts. Such a methodology may be useful both in designing new bridges, in estimating their performance over time under given environmental and service condition, and for existing bridges, in assessing their residual bearing capacity in the damaged state after a certain period from construction