Nonlinear Analysis of Beams Prestressed by Unbonded Cables

The problem of a beam prestessed by means of a stretched cable slipping along a path rigidly linked to the beam is analyzed in a more general and unitary way than in previous formulations by considering nonlinear materials and generic cable paths. Moreover, the writers intend to show that the weak form of the problem, based on total potential energy minimization, is far more convenient than the strong form, based on local equilibrium, from both formal and numerical points of view. The weak form expresses global equilibrium conditions, and describes in a more natural way the physical behavior of this system in which the slipping cable joins the local equilibrium to the global deformation. A numerical method for the solution of the nonlinear problem is provided by using the Ritz approximation method, and results concerning a concrete beam are reported.