Research On Lean Prefabricated Structure System And The Connecting Of Bar

With the increasing proportion of prefabricated structural systems in the development of the construction industry,the related structural forms are becoming more and more abundant.However,the problems of the existing prefabricated structural systems in the practice process have become increasingly prominent.This article is based on the prefabricated assembly structure patents of the research group: a prefabricated node and a prefabricated frame structure and its construction method,to study the connection of reinforcing bars under precise connection distance.In this paper,the tensile and tensile properties of rebar straight thread sleeve connectors with uniaxial tension,high tensile stress,and large deformation are tested experimentally.The main results are:1)Analyze and demonstrate the beam-column integrated prefabricated reinforced concrete structure system;2)Designed a fixed steel straight threaded sleeve connection test device;3)Several sets of straight steel threaded sleeve connection test pieces were designed.The main results of the test were as follows:a.In the unidirectional load test,the peak loads measured by connecting the 22 mm,25mm and 28 mm steel bars with straight threads,and the derivation of the tensile strength values,except for the 25 mm and 28 mm diameters,has a low peak load on the single specimen.The failure mode is the destruction of slip wire.The damage of the uniaxial tensile test of the other rebar specimens is broken,and the damage position occurs at the exposed thread of the straight threaded sleeve connection of the steel bar;b.In the large deformation repeated tensile and compressive load tests,the peak loads of the three diameter specimens are all good,and the derivation of the composite tensile strength values and residual deformation values meet the test expectations;c.In the high-stress repeated tensile-compression load test,there were more specimens with slide wire failure,one with a diameter of 22 mm,and two with a diameter of 25 mm and 28 mm.After examination and analysis of the test results of the test pieces,the factors of wire breakage occurred: Errors between the threads at the two ends of the steel bar connector and the threads in the straight thread sleeve,and the internal threadscould not be checked exactly.There is a deviation between the structure of the entire connector and the axis along the line of the rebar and the sleeve,and the entire connector is subjected to force,which will bring secondary effects.The installation of the steel bar joint structure,the use of artificially applied torque,and the time effect between the completion of the installation of the different bar joints have a certain influence on the peak loads experienced by the bar joints.4)Based on the analysis and comparison of the simulation analysis and the test,the length of the thread in the threaded connection section of the straight thread sleeve length and the steel straight thread sleeve connection is established.