| In recent years,the problems of poor structural durability and material aging have been common in public buildings,especially steel roof truss is prone to steel corrosion.This paper,on the basis of consulting a large number of relevant literatures at home and abroad,applies Glass Fiber Reinforced Polymer(GFRP)to beam string structure and truss structure,a new type of GFRP string-support beam and GFRP truss beam are proposed.These two new components are made of hat-section chords and V-shaped webs connected by epoxy bolts or cables,which have the characteristics of light weight,high bearing capacity,high standardization,convenient construction and assembly.In this paper,the vertical bearing capacity of the two components is studied and the finite element simulation is analyzed,the main research work and achievements are as follows:1)Designing two groups of GFRP string-support beam specimens and three groups of GFRP truss beam specimens;introducing the composition of the two specimens,the cross-sectional shape and size of each component,the manufacturing process of hat-section chords and V-shaped webs,and the assemble process of the specimens in details.2)Taking two groups of 2.7m,4.2m span string-support beams and three groups of 6.0m span truss beams as the research objects,the vertical bearing capacity test was carried out.The paper describes the test device and loading scheme,and introduces the test position and method of displacement,strain and cable tensile force of each group of specimens.At the same time,a series of material property tests were carried out on GFRP profiles,epoxy bolts and cables,and the relevant mechanical parameters such as the strength and elastic modulus of the materials were obtained.3)Through the analysis of the bearing capacity test results of five groups of specimens under vertical load,the ultimate bearing capacity,failure and deformation characteristics of the string-support beams and truss beams are obtained.Among them,the 2.7m span and 4.2m span string-support beams lose their bearing capacity due to the excessive overall deformation of the specimen and the local buckling of the Vshaped web;the failure form of another three groups of 6m span truss beam is that the end V-shaped web is pulled off or cut.The bearing capacity and mid-span deflection of the five groups of specimens all meet the requirements of the normal service limit state of the roof truss.4)The test results of the bearing capacity of truss beams show that under the action of vertical load,for truss beams with 6m span,when using V-shaped webs at the same height,the more the number of V-shaped webs,the higher the ultimate bearing capacity and overall stiffness in the normal use stage.At the same time,increasing the height of the V-shaped webs has a more significant effect on the improvement of the mechanical properties of the truss beam.In the actual project,the V-shaped web with a height of 400 mm or 500 mm should be selected flexibly,and the number of V-shaped webs should be reasonably increased or decreased to meet the design requirements.5)The chords and V-shaped webs are simplified into anisotropic shell elements,and ABAQUS software was used to establish two groups of 2.7m span and 4.2m span GFRP string-support beams and three groups of 6m span GFRP truss beam finite element model,the vertical bearing capacity,failure form,span deflection of finite element simulation,and comparative analysis the experimental results,which verifies the correctness and rationality of the finite element modeling method in this paper.Through experimental research and finite element analysis,it can be seen that the new type of string-support beam and truss beam in this paper have great vertical bearing capacity and overall stiffness,lightweight,high strength,high degree of standardization,easy construction and assembly,and have good application prospects,which provides a theoretical basis and guidance for the further exploration and research of GFRP string-support beams and truss beams. |
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