engleski

Numerical model of prestressing tendons embedded into the 3D concrete element

In civil engineering practice, numerical modelling of reinforced concrete and prestressed concrete structures is mainly used as a tool for the assessment of the structural safety of non-standard reinforced and prestressed concrete structures and has been studied by many authors. This paper presents a numerical treatment of prestressing tendons in 3D numerical modelling of reinforced and prestressed concrete structures. The prestressing tendons and reinforcing bars are embedded into the 3D concrete element and both are modelled by one-dimensional isoparametric three-node elements. These elements make it possible to model arbitrarily curved prestressing tendons in space. Three-dimensional twenty-node or twenty-seven-node elements are used for concrete modelling. The attention is mainly focused on the description of the tendon element and its compatibility with the parent element. Equations of the finite element method have been obtained from the incremental form of the principle of virtual work. The influence of the prestressing tendon on the concrete is modelled by distributed normal and tangential load along the tendon and the two forces concentrated on the anchors. Tendon can be prestressed on one end or at both ends. The prestressed equivalent nodal forces are computed to get the contribution of the prestressing to the global stiffness. The developed model makes it possible to compute the losses which result from concrete deformation and losses in the anchorage zone. The numerical examples illustrate the application of the described model to analysis of beams with different cross-sections.

concrete structures; numerical model; prestressing tendons; finite element method; prestressing

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