three-dimensional nonlinear finite element modeling for bond performance of ribbed steel bars in concrete under lateral tensions

Development of experimental studies in bond behavior between deformed bar and concrete under complex stress conditions in the last 2 decades is significantly affecting the concrete design specification. this article presents a rib-scale finite element model (fem) to study the bond behavior of deformed bar in concrete under lateral tensions. in this model, detailed modeling including the reinforcing bar ribs and the concrete keys in contact region is realized with real geometric parameters. at the concrete–bar interface, surface-to-surface contacts with tie constraints are used and relative sliding or separation between contact surfaces are inhibited; adhesion between concrete and deformed bar is ignored. a user-defined subroutine named vusdfld in abaqus software was incorporated into the concrete damaged plasticity (cdp) model to acquire more accurate concrete constitutive relations. the fem is calibrated using pullout test data from published papers. the simulation results show that all specimens failed in splitting mode. the lateral tension is an adverse factor on the bond property between steel bar and concrete, both the ultimate bond strength and the slip at the peak bond stress decrease with the increase of the lateral tensions. comparison of computational simulation with the experimental data indicates that the proposed model gives a reasonable prediction of the bond stress–slip curves as well as the concrete crack patterns.