High-resolution finite element modeling for bond in high-strength concrete beam

This study presents a physics-based rib-scale finite element (FE) model to study bond-zone behavior for spliced longitudinal bars in reinforced concrete beams subjected to monotonically increasing loading. In this model, a high-resolution mesh is used in the vicinity of the bar-concrete interface to capture the geometry of the ribs on the reinforcing steel. At the concrete-bar interface, a contact formulation that properly represents normal and frictional force transfer is used; adhesion between concrete and steel is ignored. The FE model is calibrated using data from beam splice tests performed by Ramirez and Russell [1]. It is observed that concrete tensile strength and tangential friction at the concrete-steel interface determine simulated response; these quantities are calibrated to provide accurate simulation of experimental results. The calibrated model provides results in good agreement with test data. Load-displacement response as well as concrete crack patterns are accurately simulated, and the proposed model can distinguish between the behavior of uncoated and epoxy-coated deformed bars as well as simulate the impact on bond strength of confinement provided by transverse steel.