engleski

Non-linear finite element analysis of post-tensioned concrete structures

Numerical modelling of non-linear prestressed structures has been studied by many authors. The model presented in this paper is applied to non-linear analysis of post-tensioned concrete structures, partially or fully prestressed. The stress in prestressed tendons is decreased as a result of various influences which directly affect the bearing capacity of the structure. Consequently, all changes should be computed as precisely as possible. The model developed in this paper makes it possible to compute friction losses, losses in the anchorage zone caused by concrete deformation and standard losses caused by the short-term linear and non-linear deformation of concrete. The prestressed tendons and reinforcing bars are embedded into the concrete. They were modelled by one-dimensional isoparametric three-node elements. These elements make it possible to model generally curved prestressing tendons and reinforcing bars. The influence of the prestressed tendon on the concrete is modelled by distributed normal and tangential load along the tendon and the two forces concentrated on the anchors. The computation for post-tensioned structures is organized in phases. In the phase whivh precedes the prestressing of the tendons the structure is computed taking into account yhe dead load and one part of the permanent load. In the prestressing phase the tendons are tensioned individually. The prestress force can be applied at once or incrementally. In the third phase, which follows the tensioning of all tendons, the structure is computed taking into account the remaining part of the dead load and the live load.

non-linear analysis; post-tensioned concrete structures

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