Research On The Mechanical Properties Of Fabricated Steel-concrete Composite Beams

Steel-concrete composite beams combine the advantages of steel and concrete structures and are widely used in various types of buildings and bridge structures.With the development of industrialization of buildings,fabricated steel-concrete composite beams have emerged.Assembled steel-concrete composite beams have the advantages of “prefabrication” and “rapid construction”.In actual engineering,the amount of onsite wet work can be reduced and the construction period can be shortened.In this paper,theoretical and numerical analysis is carried out for the structural characteristics of fabricated composite beams.The main research work is as follows:(1)Using the finite element software ABAQUS to establish the existing experimental finite element model and carry out static analysis,the shear bearing capacity and load-slip curve of the stud connection are obtained.The results of the finite element analysis and the test results are verified.Feasibility of finite element simulation.(2)According to the Eurocode 4,19 sets of experimental finite element models were established,and ABAQUS was used for parametric static analysis to study the shear strength of the stud connectors in the shear strength of the concrete strength grade,stud diameter and stud yield strength.Force and load—the effect of the slip curve.Studies have shown that the most important factors affecting the shear capacity of studs are: concrete strength grade,stud diameter and stud yield strength.As the concrete strength level in the shear slot increases,the shear bearing capacity of the stud connector increases,but the growth rate slows down.As the diameter of the stud and the yield strength of the stud increase,the shear bearing capacity of the stud connector increases linearly and the maximum slip increases.(3)Carrying capacity analysis and vibration modal analysis of four sets of fabricated steel-concrete composite beams with different shear connection degrees.The research shows that the interface slip effect reduces the bending stiffness of the composite beam and increases the deflection deformation,which in turn reduces the vertical bending mode frequency of the composite beam.And as the degree of shear connection decreases,the amplitude of the vibration mode frequency decreases.(4)Firstly,the basic concepts of fatigue are introduced,and then three theoretical methods for evaluating the fatigue life of stud connectors are introduced: nominal stress method,local stress-strain method and damage tolerance method based on fracture mechanics.Finally,comparing the three fatigue life evaluation methods,combined with the force characteristics of the stud connectors,the nominal stress method was selected to evaluate the fatigue life of the stud connectors.(5)Fatigue analysis software Fe-safe was used to analyze the fatigue performance of stud connectors,and the effects of stress amplitude,upper and lower load limits,concrete strength grades in shear slots on fatigue life of stud connectors,and EC4 were studied.The specification values are compared.Referring to the existing stud stress amplitude-fatigue life relationship,the S-N curve required for the fatigue analysis of the stud connectors in the assembled composite beam is fitted according to the finite element analysis data.