Finite element formulation for geometric and material nonlinear analysis of beams prestressed with external slipping tendons

In this paper a finite element formulation of a geometric and material nonlinear analytical model for externally prestressed beams is illustrated. Differently from existing methods starting from the linear theory and then including the tendon eccentricity variation, the analytical model adopted is based on a nonlinear kinematical theory. Thus a complete description of the nonlinear interactions between tendon and beam is given. The interactions between axial and flexural fields of the beam are also included. The numerically simulated response is verified by comparison with experimental tests available for concrete beams and steel–concrete composite beams prestressed with external tendons.