Constitutive Relation Of Steel Bar Connected By Half Grouting Sleeve Applied For Fabricated Concrete Structure

Fabricated structure is a new direction of research and development in the field of construction in China.In the numerical simulation and performance analysis of the fabricated structure,how to set up the reasonable model of the vertical connection of the fabricated structure is considered as the key and difficult point of the research.In our research group has been completed prefabricated reinforced concrete shear wall test based on,this paper on the assembly type structure is used in the semi grouting sleeve connection reinforced specimens,a series of tests were carried out to study,and through the experiment was extracted from the semi grouting sleeve connection reinforced test equivalent constitutive relation.At the same time,this paper in the simulation of prefabricated reinforced concrete shear wall,semi grouting sleeve connection reinforced part regarded for elongate members of homogeneous materials,and give the equivalent constitutive relationship is calculated,the obtained simulation results and experimental results were in good agreement.In the course of the study,this paper uses a variety of methods such as experiment,theoretical analysis and simulation.The main researching content is as follows:(1) In this paper,the monotonic tension test of 21 half grouting sleeve joints and the cyclic loading test of 8 half grouting sleeve connected with the steel bar under two different cyclic loading modes are finished.In the monotonic tension test,the stress- strain exhibits 4 stages,which are linear growth,nonlinear growth,equivalent yielding and post strengthening failure.And the elastic modulus of the specimens in the linear growth phase is about half of the elastic modulus of the reinforcement.Under cyclic loading,the elongation rate is related to the stress state and cycle times.Under cyclic loading,the elongation of specimens under cyclic loading is smaller than that under monotonic tension.(2) Based on the above experiments,the monotonic tensile test curve is simplified according to the feature points,and the constitutive model of steel bar is presented under monotonic tension condition.Linear regression analysis using the statistical software SPSS to analyze the relationship between multiple factors and multiple factors.The constitutive parameter fixing method and the recommended values of feature points in the model(3) In this paper,the hysteretic model of the skeleton line is recommended,and the simulation of the cyclic loading test of the steel bar is realized in the OpenSees software.The comparison test results are in good agreement,which indicates that this method can simulate the actual situation of reinforced connection under cyclic loading.(4) The comparative analysis of different modeling methods for the assembled shear wall specimens which have been completed by using ABAQUS software.The method is in good agreement with the experimental results.The method is safe and reliable.At the same time,through the comparison between different methods,it is considered that the simulation method is more accurate than the existing method,and the simulation results are more in line with the actual force characteristics of the assembled shear wall.