NONLINEAR FINITE-ELEMENT ANALYSIS OF POSTTENSIONED CONCRETE STRUCTURES

Presents a non-linear numerical model for the computations of post-ten sioned plane structures. Generally curved prestressing tendons and rei nforcing bars are embedded into the concrete and they are modelled ind ependently of the concrete mesh using one-dimensional curvilinear elem ents. Among the losses which influence the decrease in the prestress f orce, it is possible to compute the losses caused by friction between tendons and the concrete, the losses which result from the concrete de formation and the losses in the anchorage zone. The computation for po sttensioned structures is organized in phases: the phase preceding pre stressing (Phase I), the prestressing phase (Phase II) and the phase f ollowing prestressing (Phase III). The load is applied incrementally u ntil failure. The model is tested on a number of examples.