Mechanics of Damage at Steel-Concrete Interface in RC Structures

Abstract

AbstractOne of the major problems affecting present infrastructure is shortening of service life due to durability issues. A large number of steel-concrete composite structures fail not from overloading but because of durability issues. One of the main causes of short service life is corrosion of steel in steel-concrete composite structures. The current state of practice in design codes deals with this issue by assuming a perfect bond between steel and concrete for design considerations and provision of minimum cover depth for prevention against corrosion. The degradation at the interface that can have long-term deteriorative effects on strength and durability cannot be addressed with the present framework. Thus a need for more exact design and analysis recommendations is needed to address and deal with the issue of durability caused by corrosion. The objective of this study is to investigate the effect of corrosion at the steel-concrete interface on the structural behaviour of steel-concrete composite structures through numerical methods. The mechanics of degradation of the interface have been studied using finite element method. Effects of corrosion at the steel-concrete interface such as weakening of the interface, reduction of structural steel area and de-lamination at the interface have been studied. These phenomenon can be modelled using finite element approaches. Modelling of corrosion using solid elements presented with problems of mesh refinement, coupling damage with a constitutive response. To address the above, a UEL has been implemented in ABAQUS using a traction separation law based on the Mohr-Coulomb failure criteria, which will be used to model corrosion at the interface. Experimental data on corrosion samples were used to obtain the material properties. The developed model shall provide a way to study the effect of the presence of varying amounts of corrosion on the performance of a structure. The present study aims to provide a robust numerical scheme to analyse composite structures with varying degrees of corrosion. On the basis of obtained results, recommendations for addressing deterioration due to corrosion would be recommended.KeywordsSteel-concrete interfaceCorrosionFinite element method