ABSTRACT
Deterioration due to corrosion has been a growing concern in the last decades since it results in a reduction of the cross-section of the reinforcement, cracking and possible loss of the concrete section. Apart from deterioration, also the awareness of the importance of structural robustness has increased due to several failures with progressive collapse. Due to the activation of tensile membrane action in reinforced concrete slabs at large deformations, an alternate load path can be developed which can significantly increase the structural robustness. In this contribution, a validated numerical model for the tensile membrane behaviour of reinforced concrete slabs is used to investigate the influence of corrosion effects on this membrane behaviour.
The two-step analysis developed by (Sánchez et al., 2010) is adopted: first a cross-section analysis is performed, followed by a longitudinal analysis of the structural member. During the first analysis, the expansion of the reinforcement is simulated, resulting in cracking of the concrete (Figure 1). Subsequently, the results of this first analysis are projected on the longitudinal model. Crack pattern in concrete due to corrosion. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig178_1.tif"/>
The methodology is capable of reproducing many of the mechanical effects induced by corrosion processes in reinforced concrete elements, e.g. expansion of the reinforcement bars due to the corrosion product accumulation, damage and crack pattern in the surrounding concrete, degradation of steel-concrete bond stress transfer, net area reduction in the reinforcements and the influence of all these mechanisms on the structural load carrying capacity predictions.
It was observed that even for small corrosion levels, there was a significant decrease of the ultimate bearing capacity of the slab (Figure 2). Sample of a figure caption. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig178_2.tif"/>
This decrease was mainly attributed to the reduced properties of the reinforcement, since there was no difference found between the ultimate load obtained through the two-step analysis and the one obtained through the analysis where only the reduction of the reinforcement properties was considered. The reduction of the properties of the concrete had an influence on the load-peak caused by compressive membrane action. Hence, only the failure load of slabs failing due to compressive membrane action was influenced by the two-step analysis.
