Numerical Simulation On Bond-slip Relationship Of Reinforced Concrete And Crack In Reinforced Concrete Beam

Numerical simulations of crack processing and bond-slip relationship between steel reinforcement and concrete are always hot and difficult topics in finite-element analysis of reinforced concrete structures. As the durability problem of concrete structures become more important and the bonding degradation must be considered in seismic design, considering structural cracks and bond-slip become more import. Because of the complexity of the problem and limitation of test condition, it is very difficult to obtain accurate and complete data of bond-slip between steel reinforcement and concrete. In this paper, pull-out test, cracking and size effect of reinforced beam considering bond-slip are numerically simulated. The major contents are summarized as follows:1. In this paper, according to the space axisymmetric model, a separate-finite element model of a pull-out test is built, in which cohesive zone model is imported to simulate bond-slip. Results of the calculation have good agreement with the experimental data.2. Based on Extended Finite Element Method (XFEM), several beams are analyzed in the cases of without considering bond-slip and considering bond-slip from the beginning of loading to cracking damage, no size spring elements are used to simulate bond-slip in these models. Results of the calculation have good agreement with the experimental data. Relationships between load and displacement, crack width, steel stress, bond strength are also obtained, which can not be obtained in tests.3.3D finite element models of 12 reinforced concrete beams without stirrup and 36 reinforced concrete beams with stirrups are built, which consider bond-slip. Shear-carrying capacity'and horizontal strain in the longitudinal direction of beam are compared with different concrete strength grades, effective height and span of stirrup, and the results show that size effect also exists when there are stirrups.