2008 Volume 6 Issue 1 Pages 227-242
A high-cycle fatigue constitutive model for concrete joint interfaces is proposed and the direct path-integral scheme for RC-PC structures with junction planes is presented. Both cyclic pullout and the associated dowel action of reinforcing bars are formulated at a crack/joint section in terms of the relative displacement derivatives of a pair of joint planes. The proposed differential formula is verified by high cycle fatigue experiments of dowel bars and pullout of reinforcement crossing a joint in structural concrete. In conducting the direct path integral of the constitutive equations, a logarithmic time integration method is adopted so as to achieve highly accelerated computation with reasonable accuracy. The scheme is applied to the assembly of pre-cast pre-stressed concrete members with reinforced concrete joints for the purpose of life-cycle assessment. A mechanics-based discussion is presented of the different fatigue life observed in precast slabs with localized discrete joints and in monolithically constructed reinforced concrete, where dispersed cracking develops.