Research On Shear Capacity Of Precast Truss Steel Reinforced Concrete Box Girder

With the development of building industrialization,steel reinforced concrete structures have been widely used in buildings and bridges.In trussed steel reinforced concrete structure,high strength steel truss and concrete together improve the integrity and crack resistance of the structure.If factory precast,welding or bolt anchoring in the construction site are used,and then a little wet work is used to form a stable whole structure,which can meet the needs of modern industrialization construction.Box girder is widely used in bridge engineering because of its space sealing and good mechanical performance.At present,the research on the shear resistance of box girder is not mature at home and abroad,the code has not made a clear provision for the calculation of box girder shear strength,and the research on steel reinforced concrete box girder is even less than that of steel reinforced concrete box girder.Therefore,it is of great significance to study the shear performance of precast truss steel reinforced concrete box girder.Taking the reinforced concrete box girder for the reference,and combined with "Study on Shear Capacity of Precast Truss Steel Reinforced Concrete Box Girder" by national natural Science Foundation Project,a total of 6 prefabricated truss steel reinforced concrete box beams are designed and manufactured for web spacing and shear span ratio,and the static load test and theoretical analysis are carried out.The main work is as follows:(1)The prefabricated assembly technology,the advantages and disadvantages of steel reinforced concrete structure and the development of shear analysis of steel reinforced concrete box girder at home and abroad are reviewed.Combined with the research direction of this paper,the main research contents of this paper are put forward.(2)Based on the shear capacity test of precast truss steel reinforced concrete box girder,the cracking load and ultimate load of the members during loading are recorded,and the failure pattern of the test beam is analyzed,including the development law of deflection of test beam and strain of vertical web and oblique web with the change of load.The test results show that the smaller the shear span ratio and the smaller the spacing between web members,the higher the shear bearing capacity of truss type steel reinforced concrete box girder is;(3)The function and application of the non-linear finite element software ABAQUS are briefly introduced,which indicates in the process of modeling in ABAQUS,the shear behavior of the test members is analyzed by the nonlinear finite element software ABAQUS,and the failure process of the test beam can be well simulated.The results are in good agreement with the experimental results,indicating that it is feasible to use the nonlinear finite element software ABAQUS to analyze the shear bearing capacity of precast truss steel reinforced concrete box girder.(4)In this paper,several existing shear analysis theories are analyzed.Based on the tension-compression bar theory,the shear capacity formula of truss steel reinforced concrete box girder is derived,which is in good agreement with the experimental results and it is shown that the formula established for calculating the ultimate shear capacity is reasonable.