Finite element modelling of RC slabs retrofitted with CFRP strips under blast loading: Fid-Bau Portal

Finite element modelling of RC slabs retrofitted with CFRP strips under blast loading

Maazoun, Azer / Matthys, Stijn / Atoui, Oussama / Belkassem, Bachir / Lecompte, David

Highlights • The blast response of strengthened slabs can be effectively improved by means of FRP strengthening. • The Winfrith concrete model gives a good prediction of the blast response of the RC slabs with and without EBR. • The tiebreak contact algorithm based on the dynamic increase factor at the interface between CFRP strips and concrete provides a valid prediction of the maximum strain in the CFRP strips.

Abstract This paper presents nonlinear finite element (FE) simulations to predict the structural behavior of simply supported reinforced concrete (RC) slabs retrofitted with carbon fiber reinforced polymer (CFRP) as externally bonded reinforcement (EBR) and subjected to the blast loads in order to evaluate the effectiveness of using the CFRP strips as EBR for blast protection. The objective of this paper is to develop detailed numerical models in order to predict the blast response of non-retrofitted and retrofitted RC slabs during the inbound and rebound phases. A plastic material model including the strain rate effects of the material and able to predict the cracks is used to model the concrete. An elasto-plastic material model and an elastic material model are used to model the steel reinforcement and the CFRP strips, respectively. The bond interface between concrete and CFRP strip is simulated using a special contact algorithm including the strain rate effect at the interface between concrete and CFRP strip with failure criteria. The numerical results are validated by experimental tests. The maximum deflections, crack distribution and strain evolution in the steel reinforcement and in the CFRP strips found by the numerical analysis are in good agreement with the experiments. The concrete material model gives a good prediction of the blast response of the RC slab with and without EBR. Increasing the amount of the CFRP strip reduces the maximum deflection at the mid span of the slabs and the strain distribution in the steel reinforcement and in the CFRP strip. Parametric studies with respect to CFRP width and CFRP thickness are performed in order to evaluate the effects on the blast response of the RC slabs.