Analytical modelling of the bending behaviour of hybrid composite-concrete beams: Methodology and experimental validation

The advantages of high performance composite materials have stimulated their use as reinforcement in concrete structures as well as the research on hybrid composite-concrete elements. For the design of these hybrid structures - with often complex geometries - the standard concrete calculation rules, based on official codes such as Eurocode 2, are often not elaborated enough. Moreover, these standard models are limited or simplified to a linear behaviour and do not even allow the integration of nonlinear reinforcement behaviour. In this paper, the authors propose a general calculation methodology to simulate analytically the structural behaviour of hybrid beams, including their ultimate loadbearing capacity and deflection. This methodology introduces an original search algorithm that reduces the computation time significantly without losing accuracy. The analytical model is validated by ten experiments on 3-m-span hybrid beams with differing geometry. The experiments demonstrate the accurate prediction of the analytical model both for the load-deflection behaviour and for the occurring strains, and confirm the model assumptions made. Moreover, the structural feasibility of the proposed hybrid beams is demonstrated as they exhibit a sufficient loadbearing capacity and stiffness. This structural performance in combination with the ability to predict the behaviour reveals a great potential for future structural applications.