Study On Composite Continuous Beam Of Fabricated Steel-high Performance Cement Matrix Composites

In recent years,China is vigorously developing a new type of fabricated composite beam structure.The assembled composite beam structure has a huge development space in the field of bridge engineering.Compared with the traditional fabricated structure,the assembled composite beam structure can effectively avoid the cracking of the lower edge concrete,reduce the beam height,and speed up the construction speed of the project,and it can also generate great ecological benefit value.However,for the continuous beam structure,both the traditional fabricated structure and the composite beam structure inevitably face the problem of cracking of the roof of the concrete roof caused by the negative bending moment at the fulcrum,which causes a series of disease problems,reduces the service life of structure and increases the cost of maintenance and inspection costs.In this paper,the material and beam test research and analysis are carried out for the characteristics of the assembled composite continuous beam structure.The main work and research contents are as follows:(1)For the actuality of the fitting engineering,a high-performance cement-based composite material with a cubic compressive strength of 115.92 MPa and a cubic splitting tensile strength of 18.68 MPa was prepared under standard curing conditions.The mechanical properties of the materials were tested and the influence of steel fiber content on the strength of the materials was studied.The optimal blending amount of steel fibers was obtained and the fitting formulas of different steel fiber contents on compressive strength and tensile strength of the materials were proposed.(2)Microscopic imaging of high performance cement-based composites was carried out by electron microscopy,and quantitative microscopic parameters wereanalyzed to obtain microscopic factors affecting the macroscopic mechanical strength of the materials.(3)A total of 6 sets of studs of the same height and different diameters were subjected to the thrust test,and the relationship between the load and the relative slip amount of the studs and high-performance cement-based composites with different diameters was obtained.The shear capacity of the stud obtained in the field test is compared with the standard value of China,and the error between the actual value and the theoretical standard value is obtained.(4)Carry out the failure test of the assembled composite continuous beam without reinforcing steel bars,observe the connection condition of the prefabricated section and the cast-in-situ section and the structural failure development form,and measure the structural failure load,the deflection and strain of the corresponding position.(5)Using the finite element software ANSYS to model and calculate the test beam structure.The results of the numerical analysis are compared with the field test results to verify the accuracy and rationality of the ANSYS calculation results.