Analysis of pre-tensioned structures by means of a constitutive serial-paralel rule of mixtures

A. CORNEJO; L. BARBU; C. ESCUDERO; X. MARTINEZ; S. OLLER; A. BARBAT

Congreso; International Conference on Structural Integrity and Durability, ICSID 2017, Fatigue and Fracture at all Scales Dubrovnik; 2017

The main purpose of this paper is to develop a reliable method based on a three-dimensional (3D)finite-element (FE) model to simulate the constitutive behaviour of reinforced concrete structuresstrengthened with post-tensioned tendons taking into account the reduction of the pre-stressing stressdue to the steel relaxation. The pre-tensioned concrete is modelled as a composite material whose behaviouris described with the serial-parallel rule of mixtures (S/P RoM) [1-3] whereas the stress relaxationof the steel is simulated using a viscoelastic model called Generalized Maxwell. A 3D FE modelwas used, where the nonlinear material behaviour and geometrical analysis based on incremental?iterative load methods were adopted. Validation by comparison with the analytic solution will be donefor the case of a concrete beam with a parabolic pre-tensioned steel tendon embedded and some viscoelasticcases are performed in order to perceive the behaviour of the Generalized Maxwell model.Several examples are shown where the capabilities of the method on large scale structures are exhibited.