Research On Bending Behavior Of GFRP-concrete Composite Beams With Slotted Shear Connector

In order to compensate for the potential safety risks and economic losses caused by steel deterioration and corrosion in traditional reinforced concrete structures and steel-concrete composite structures,GFRP-Concrete composite structures with high bearing capacity and strong corrosion resistance have been favored by researchers.At present,Bolt connector and PBL shear connector are the main connections at the interface of the composite structure,while the research on the selection of shear bond connection with profiles is less.Therefore,this paper takes GFRP-Concrete composite beams with slotted shear connector as the research object.On the basis of meeting the deflection limit of the composite structure specification,ABAQUS finite element analysis and four-point bending test are used to research its bending performance.The main research contents are as follows:Firstly,17 GFRP-Concrete composite beams with slotted shear connector were designed,and the four-point bending test was carried out on them by changing the four factors of shear connector spacing,flange width,shear connector height and web thickness through ABAQUS finite element analysis software.The results show that the shear connector encrypt spacing,increase shear connector flange width and height can effectively improve the bearing capacity of GFRP-Concrete composite beams and the interface slip resistance,and change the web thickness of only the interface slip resistance increased,among them,the change of shear connector spacing was most evident influence on composite beams.Secondly,on the basis of finite element analysis selected three beams of different shear connector spacing four-point bending test,expounds the final failure pattern of composite beams,the composite beam end load-slip curve,across different loaddeflection curve and the load and the strain of each cross section curve,and the test results of the load,load-deflection curve and load-slip curve compared with the finite element results,two kinds of curve trend test results can be a good match.Then,combining with the specification and test results,a reasonable assumption is adopted to deduce the calculation formula of the flexural capacity of this kind of composite beam,and the experimental results are compared with the theoretical calculation results.Finally,on the basis of considering the interface slip of composite beams,the improved method of reducing stiffness and the method of combination coefficient are introduced,and based on the existing research,a combined coefficient calculation model is established to theoretically calculate the stiffness and deflection of the composite beam and compare it with the experimental values.The calculated results of the combined coefficient method are close to the experimental results,and when n is1.75 in the proposed calculation model,the calculated results are in good agreement with the experimental results,which can provide a reference for the calculation of the stiffness and deflection of such composite beams.