Research On Shear Resistance Of FRP Perforated Plate Connector

In recent years,FRP-concrete composite structure has been widely used and developed.FRP perforated plate connector is a commonly used shear connector in FRP-concrete composite structure,And its shear resistance directly determines the collaborative work ability between FRP and concrete.The study based on the National Natural Science Foundation Youth Fund project "FRP/steel-concrete composite bridge deck beam mechanical performance analysis.test and design method" to explore the mechanical properties of FRP shear connectors and concrete connections.The main contents are presented as follows:Firstly,the study made has a brief review of FRP material related theories,which are mainly related to the micro-mechanical and macro-mechanical properties of composite materials,as well as expounding the relevant strength criteria and main failure modes of composite materials,load analysis of finite width plates with holes,calculation of stress concentration factors and other issues etc.It provides a theoretical basis for subsequent research analysis and the development of finite element numerical simulation.Secondly,11 FRP perforated plate concrete specimens has been designed and manufactured,and monotonic pull-out tests have been carried out to explore the influence of the number of openings,the size of the aperture,the presence,size and type of the through reinforcement in the hole,and the thickness of the plate on the ultimate bearing capacity of the perforated plate connector.The test results show that there are two main failure modes of the connector.namely the concrete tenon failure in the hole and the shear failure of the perforated plate;The diameter of the opening,the number of openings and the plate thickness have a greater influence on the shear bearing capacity of the GFRP perforated plate;In the mode of shear failure of the open plate,the increase of pore size and the addition of the through bars have little influence on the ultimate bearing capacity.Thirdly,based on the experimental phenomena of the test process,failure mode and measured data,referring to the existing bearing capacity formula of FRP perforated plate connectors,the empirical calculation formula and the bond-slip theoretical model of the bearing capacity in this paper are obtained by regression fitting with mathematical analysis software.Finally,the finite element software analysis modeling has been carried out.The finite element software is used to simulate the calculation examples in the relevant literature,the finite element modeling process and modeling steps of the pull-out test in this paper are introduced in detail.The finite element model can simulate the changes of stress,strain,damage and other parameters of the connector in the test process.The load-displacement curve of the simulation results is less different from the test results.The concrete strength,opening diameter and opening spacing are taken as the change parameters for analysis,and the results are in good agreement with the bearing capacity formula.