Load-deformation response of long span prestressed concrete wide beams

This paper examines the full deformational response of prestressed wide beams. The results from full-scale prestressed wide beam tests are used to validate the nonlinear numerical modelling procedures adopted in this paper. Three-dimensional modelling with detailed representation of the prestressing action is used to evaluate the response including strain distributions within the member. Simplified sectional models are also validated against the tests and detailed modelling, and are further used for an extensive parametric investigation. The parameters examined in the study include the section size, amount of non-prestressed and prestressed reinforcement, concrete strengths, and member spans. The numerical results enabled a direct assessment of the full behaviour including the forces and deflections at initial camber, cracking and ultimate state. It is shown that modelling approaches were able to predict well the overall deformation and failure modes, with the three-dimensional approach giving a more detailed insight into the internal strain distributions. Parametric studies showed that the reinforcement ratio has the greatest influence on the overall behaviour, governing the post-cracking response, compared with other parameters varied. Based on the findings, design-oriented expressions are proposed to evaluate the cracked stiffness and ultimate state deflection of prestressed wide beams. These expressions are shown to offer a reliable and practical approach for assessing the full response of such members.