Discrete Bond Element for 3D Finite Element Analysis of Reinforced Concrete tructures

Reinforced concrete structures perform well only if the transfer of tensile forces from reinforcement bars into concrete is possible. This transfer relies on the bond resistance. Therefore, for modeling of reinforced concrete structures one needs a simple, robust an drealistic model. In the present paper a discrete bond model that can be used in the three-dimensional finite element analysis of cincrete structures id described. The model response is controlled by two groups of parameters: (i) Basic model parameters: the bond strength, the shape shape of the stress-slip curves and the loading-unloading-reloading rules. ; and (ii) the parameters which depend on the geometry of the concrete specimen as well as on the stress-strain state of the reinforcement bar and concrete in the vicinity of the bar, respectively. The basic performance of the model for monotonic and cyclic pull-out load is demonstrated on a few numerical examples. Moreover, a three-dimensional finite element analysis of pull-out of a steel bar from a concrete block is carried out. The results and possibilities for further improvements of the proposed model are discussed.