Experimental Study on Shear Behavior of the Interface between New and Old Concrete with Reinforced

In order to investigate the shear behavior of the new and old concrete interface, three kinds of reinforced concrete models with new-old concrete anchorage reinforcement were designed and fabricated. The semi-cyclic loading test was carried out. The failure mode, shear bearing capacity, interfacial shear slip and stress distribution of steel bars were analyzed. The test results show that the failure mode of the old and new concrete reinforcement at the interface was split type shear failure. The shear bearing capacity of reinforced concrete is mainly related to the shear resistance of concrete and the dowel pin shear, and the maximum value is about 1.186 x 10(4) kN/m(2). The shear bearing capacity of stirrups reinforced concrete is increased by 28.5%. According to the obvious interface slip, the working state of the interface between rebar bolt and concrete can be divided into the stage of interface bonding and the stage of the friction. The lower part of the tendons is mainly cut and its upper part is shear-based. The largest stress is obtained at the interface and it decreases gradually to both ends. By analyzing the test results and relevant research, the formulas for calculating the shear capacity of the new and old concrete interface are derived. The results show that the formula of shear capacity is correct and feasible.