Experimental Study On Bond Behavior Of Precast Concrete Filled Steel Bars

With the development of assembly type structure,at present most of the provinces are vigorously promoting the assembly type structure,and some provinces and cities the corresponding norms,the development of prefabricated construction system in line with the current trend of social development,mainly due to the current form of residential structure for precast concrete shear wall structure system,and the mechanical properties of joints and the seam has not been solved in shear wall structure has become the problems to be solved,and the seam node after pouring concrete bond or a pulp stress in the transmission of force,so the reference European proposal RILEM-CEB-FIP designed 33 components to study concrete preformed reinforcement bonding performance through this hole grouting.Mainly completed the work.(1)refer to the European RILEM-CEB-FIP 33 component design proposal has verified that the bond form is really reliable,considering the diameter of steel bar,concrete strength,strength of grouting material,spiral stirrups stirrup and the anchorage length of the five factors on bond performance impact,making the test of bonding performance,the components found happened the steel yield failure and bond failure.It was found that the C50 and C60 and the length of 5D were all damaged,so it was considered that the C50 and C60 and the anchorage length of 5D could not be used as engineering application.(2)in the method of anchorage zone layout of strain gauge or equal strain through this test,and then through the matrix method has been reinforced stress distribution along anchorage length in Shuangfeng,namely the loading end and free end of the bond stress is higher than the middle section of the bond.(3)by considering the diameter of steel bar,concrete strength,strength of grouting material,spiral stirrups stirrup and the anchorage length of the five factors on the influence of ultimate bond strength,obtained the empirical formula of ultimate bond strength,and compare it with the measured error is 2.9% of ultimate bond strength,in the allowable range to design as the basis for the use of.(4)in this paper,the constitutive relation of bond stress free end slip is established by using the continuous curve model,which is a quadratic curve,and the stiffness of the member is calculated by the finite element method.In this paper,the bond slip curve model is more accurate to reflect the bond between reinforced concrete,and the form is simple,it is more convenient to apply in engineering or finite element...