Deformation Analysis Of GFRP-Concrete Composite Beam Considering Interfacial Slip And Shear Deformation

The research and application of new materials and composite structures is an important direction for the development of bridge engineering.FRP is a kind of high performance material with lightweight,high strength and good durability.The composite beams made of FRP and concrete is competitive in medium and small span bridges.Since the stiffness of FRP profiles is small,the deformation becomes the key to control the structural design.In this paper,the deformation calculation method and the influence of parameters of GFRP-concrete composite beams were studied through deformation test,theoretical analysis and numerical analysis.The main work accomp-lished is as follows:1.Deformation test research was carried out to investigate the influence of different parameters on the failure mode and deformation characteristics of composite beams.The research shows that the composite beams mainly have three failure modes:concrete crushing failure,GFRP brittle failure and integral ductile failure,and there is interfacial slip effect in composite beams.When the concrete strength is low,the composite beams are in the elastic state at the early stage of loading,and the deformation increases obviously non-linear at the late stage of loading.When the concrete strength is increased to C40 or above,the load-deformation curve of the composite beams is approximately a straight line.2.Based on the static method and the Timoshenko Beam theory,the formula for calculating the deformation of GFRP-concrete composite beam considering the effects of interfacial slip and shear deformation is derived.The accuracy of the formula is verified by comparing the analytical solution with the experimental results.The analysis shows that the influence of the two factors on the deformation of composite beams decreases with the increase of the ratio of span to height,and the influence of Shear deformation is greater.3.The finite element model of GFRP-concrete composite beam is established by using ANSYS software,and the accuracy of the model considering the interfacial slip is verified by the experimental results.The model is applied to analyze the parameters of the connector and the GFRP geometry which affect the interfacial slip and shear deformation.On the basis of parameter analysis,the deformation formula of composite beams is modified by considering the effect of vertical separation.At the same time,a refined model is established to analyze the local deformation and stress distribution at the bolt joint.4.In combination with practical engineering,the deformation calculation method and numerical modeling method proposed in this paper are applied to the deformation analysis of GFRP bridge and GFRP-concrete composite beam bridge,and the practicability of the formula is verified.At the same time,the crowd load test is carried out,and the results show that the GFRP bridge has excellent structural performance under static load and impact.In this paper,the deformation analysis of GFRP-concrete composite beams is carried out,the practical deformation calculation formula is derived,the numerical model which can be used for parameter influence analysis is established.It provides a useful reference for the design calculation and engineering application of GFRP bridges.