Finite element model for pretensioned concrete beams using partial interaction theory

Abstract

Pretensioned beams are an efficient load-carrying structural system, and are usually precast. Tendons are pretensioned on a pretensioning bed, and the concrete is cast in contact with these tendons. After curing, the tendons are cut resulting in a self-equilibrating system with improved mechanical properties. The bond and slip between tendon and concrete may be simulated in different ways depending on the purposes of the model. Recent works have employed partial interaction assumptions on the modelling and simulation of pretensioned concrete beams. Analytical results have been provided giving some insight as to how a numerical modeling by the finite element method (FEM) should be developed. in this paper, a FE formulation for the linear analysis of pretensioned concrete beams is described, developed and tested. The bond-slip relationship is taken identical to the form which is used in partial interaction composite beam analysis, frequently associated to steel-concrete or other bimaterial beams. The relative merits of the ensuing formulations, the ocurrence of locking and the precision of the numerical schemes are addressed with respect to analytical solutions.