Nonlinear analysis of prestressed concrete structures using unbonded tendon model
In this paper, a numerical model for tendons is proposed based on the finite-element method, which can represent the interaction between the tendon and concrete. This model can be used for prestressing transfer processes for one or multitendons efficiently and analyze the unbonded posttensioned concrete structure succinctly. Another relevant model for representing the friction and bond effect at the interface of tendon and the concrete is also proposed at the same time. By using these models, a numerical procedure for material nonlinear analysis of prestressed concrete structures, including the time-dependent effects due to load history, relaxation of prestress, and creep and shrinkage of concrete is presented. This procedure can predict the response of pretensioned and bonded or unbonded posttensioned beam-column or plane concrete structures such as elastic and plastic deformation, cracking, and damage patterns throughout their service-load history. Finally, a numerical example is presented to verify the validity and applicability of these models and the numerical procedure.