THEORETICAL AND NUMERICAL APPROACH OF THE BOND BEHAVIOR IN BEAM TESTS USING SELF-COMPACTING AND ORDINARY CONCRETE WITH THE SAME COMPRESSIVE STRENGTH

Abstract

The present study evaluates the bond behavior between steel bars and self-compacting concrete and ordinary concrete performed in monotonically loaded beam tests, using the Finite Element Method. In the numerical model, concrete and steel bars were represented as non-linear behavior materials, combined with a model of the interaction between steel bars and concrete (contact surface). The aim was to represent the bond phenomena and the beam test result through a numerical approach, comparing these results with International Codes and formulations proposed by the literature. According to the results, the evaluation of the bond behavior for self-compacting concrete and ordinary concrete could be well predicted by some formulations, but several other formulations and the International Codes were conservative giving underestimated test results. The proposed numerical model had a good agreement with the experimental one, especially in the pre-peak branch of the load vs. slip and load vs. displacement curves. The correct prediction of the bond behavior could lead to reduced development lengths in lap spliced bars and of the steel bar ends in structural elements; besides, the use of self-compacting concrete combined with a reduced development length could lead to an optimized structure with a reduced cost. Keywords: Self-compacting concrete, bond strength, beams, finite element method, steel-concrete interface.