| The sandwich insulation multi ribbed composite wall,composed of a structural layer,an insulated layer,a protective layer and insulated connectors,it is a new composite wall which integrates the bearing,the supporting and the insulation function.As the key component of connecting structural layer and protective layer,insulated connectors are the foundation of the joint and cooperative work of composite wall.Insulated connectors have many advantages that light weight,high strength,corrosion resistance,and it is an ideal connection material.In this paper,the mechanical properties of BFRP and GFRP bars,the bond performance between BFRP bars and concrete,and the bearing capacity of BFRP composite bars with sandwich insulation multi ribbed composite panels are studied and analysed.The main research contents and conclusions are summarized as follows:(1)Six groups of BFRP and GFRP bars were made,after maintaining at different temperature,pull-out test was carried out to compare the mechanical properties of BFRP and GERP bars.Results show that: both of BFRP and GFRP bars are brittle materials,besides,compared with GFRP bars,the elastic modulus,ultimate tensile strength and ultimate strain of BFRP bars are less affected by temperature.At 80℃,ultimate tensile strength of BFRP and GFRP decreased by 9.8% and 10.6% respectively,ultimate tensile strain decreased by 20.4% and 21.5% respectively,and tensile modulus increased by 5.4% and 13.9% respectively,compared to the properties of the bars under 20℃.(2)Twenty-five groups of BFRP bars and structural concrete specimens and eightteen groups of BFRP bars and protective concrete specimens were made,to test the central pull-out of BFRP bars concrete specimens,the influence of different factors including concrete strength,bond length and thickness of protective layer,on the bond behavior of BFRP reinforced concrete specimens were analyzed.The results show that the bond length is the main factor affecting the strength of specimens,concrete strength is a less important factor,the thickness of protective layer has nearly no significant effects,when the concrete strength is C30,the thickness of the protective layer is 50 mm and the bonding length of BFRP bars in the structural layer and the protective layer is 80 mm and 50 mm respectively,the bond performance of the specimen is the best.(3)Sandwich insulation multi ribbed composite panels under four different working conditions including BFRP bars arrangement and insulation layer thickness were made,to test the one-way static loading of four composite wall panels.In composite wall,the stress process and failure mode of protective layer and BFRP bars were analyzed.The results show that the failure mode of the composite wall is divided into three stages: elastic,micro elastic and failure stage,and the mainly failure mode of BERP bars is shear or bending shear sliding failure.Moreover,Increasing insulation layer thickness can reduce the ultimate bearing capacity of composite panels and increase the relative displacement between the protective layer and the structure layer,the layout mode of BFRP bars has little influence on ultimate bearing capacity of composite wall,and the ultimate bearing capacity of single BFRP bar is 5.08~8.15 kN.(4)Using ABAQUS finite element analysis software to establish four numerical models of the test panel,and numerical simulation analysis,comparing the results of numerical simulation and experimental results.Considering the influence of the length and the thickness of the insulation layer on the ultimate bearing capacity of the BFRP bars in the composite wallboard,the numerical model of the composite wall panel is established and the numerical analysis is carried out.The results show that the influence of the change of the bond length on the ultimate bearing capacity of BFRP bars is greater than that of the structure;increasing the thickness of the insulation layer,the shear force of BFRP bar is changed from shear to shear.The ultimate bearing capacity of single BFRP bar is obtained. |
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