Numerical approach of the steel-concrete bond behavior using pull-out models

Résumé

This paper deals with the analysis of monotonic loading behavior in pull-out tests. The main objective is to
obtain a reliable numerical model to represent the steel-concrete bond behavior using previously obtained
experimental results. The tests were performed in RILEM pull-out specimen using 10 mm steel bar and
concrete with compressive strength of 30 MPa. The numerical study used Ansys® software, based on FEM
(Finite Elements Method). The numerical simulation adopted non-linear constitutive relationships to represent
the behavior of both concrete and steel. A contact surface composed of special finite elements modeled the
interface between the concrete and the steel bar, allowing a steel–concrete slip. The numerical analysis
performed with variation of the main parameters of the software permitted determining the best ones, and
choosing them to obtain a good representation of the bond phenomena. The numerical results had a good
agreement with the experimental results. Both linear and non-linear approaches represented the pre-peak
behavior, however only the non-linear model gave the best approach for the pull-out force. In addition, the
numerical results had shown the simplified model can be used to represent the steel-concrete bond behavior
reducing the processing time for current structures analysis.
Keywords: bond strength, pull-out tests, numerical approach, contact surface, finite element method.