Finite Element Simulation of Externally-Prestressed Concrete Girders

The external prestressing (EP) technique has been noticeably used in either the strengthening of deteriorated reinforced concrete (RC) structures or the construction of long-span girders. This technique has many advantages in terms of its contribution to both flexural and shear capacity of RC girders, the ease of installation, and more convenient maintenance for tendons’ inspection and replacement. Considerable number of research have been experimentally investigated the contribution of EP tendons to enhance the capacity of RC girders. However, numerous factors were found to affect the performance of EP RC girders that require further investigation. The main purpose of this study is to develop a three-dimensional finite-element model that is able to simulate the entire behavior of EP RC girders. In this model, appropriate geometrical elements are used to represent the behavior of the concrete, steel reinforcement and EP tendons. The EP tendons are modelled with truss elements connected to the concrete at specific locations, as was the case for the laboratory experiments. Sensitivity analysis is performed for finite element modelling of specimens in order to optimize the mesh size and the number of nodes per element. The numerical predictions of the finite element model are compared with various configurations and materials of EP tendons. It is shown that the numerical predictions compare very well with experimental measurements in terms of ultimate loading capacities, load–deflection relationships and failure modes. The numerical predictions are used to provide useful information of the cracking progress and strain profiles of the simulated girders.