Research On The Mechanical Properties Of Honeycomb Composite Beams With Beam End Restraints Under High Temperatur

Cellular composite beam is composed of cellular steel beam,concrete slab,and shear connectors.It not only has the advantages of high stiffness and bearing capacity of traditional composite beams,but also can save steel by using perforated steel beam web,making it easier to pass through pipelines and lower floor height,which has good economic benefits and is in line with China’s green and sustainable development under the dual-carbon target.Currently,most research on cellular composite beams focuses on components with simply supported boundary conditions,while in actual engineering,the fire resistance performance of composite beams at different locations differs significantly from that of simply supported components due to the constraints of surrounding components.Therefore,it is necessary to study the cellular composite beams in the overall structure under high temperature conditions.By summarizing the research results of domestic and foreign scholars and various national standards,suitable thermal-physical parameters and mechanical performance parameters of materials under high temperature were selected.Based on the test of cellular composite beams constrained at the end of the beam,a finite element model was established using ABAQUS software for thermo-mechanical coupling analysis.By comparing the temperature field and displacement results with the test results,the correctness of the finite element model was verified.The study investigated the effects of factors such as opening type,opening rate,span-to-depth ratio,length of the web plate,width and thickness of the flange,height and thickness of the web plate,thickness of the concrete slab,and constraint type on the fire resistance of cellular composite beams.The results show that the main influencing factors on the fire resistance of cellular composite beams constrained at the end of the beam are opening type,opening rate,height and thickness of the web plate,and thickness of the concrete slab.When other conditions are constant,the larger the opening rate,the worse the fire resistance of cellular composite beams constrained at the end of the beam.Increasing the thickness and height of the web plate and the thickness of the concrete slab can significantly reduce the deflection deformation of cellular composite beams constrained at the end of the beam under fire.The failure mode of cellular composite beams constrained at the end of the beam under fire is different from that of cellular composite beams under simply supported boundary conditions,and the fire resistance of cellular composite beams constrained at the end of the beam is significantly enhanced compared to cellular composite beams under simply supported boundary conditions.Based on the fire resistance analysis model for beam-end restrained cellular composite beams,high temperature transient and steady state analysis methods are used to analyse the fire resistance limit and load carrying capacity of beam-end restrained cellular composite beams.The effects of opening ratio,pitch height ratio,web length,steel beam size and concrete slab thickness on the fire resistance and flexural load capacity of the beam-end restrained cellular composite beams are investigated.The results show that: the opening ratio,pitch height ratio,web height and thickness have less influence on the load carrying capacity coefficient of the beam-end restrained cellular composite beam,while the flange height,web thickness and concrete slab thickness have more influence on the load carrying capacity coefficient of the beam-end restrained cellular composite beam;the load ratio,concrete slab thickness,web thickness and web height are important factors affecting the fire resistance limit of the beam-end restrained cellular composite beam,the flange width and flange thickness have more influence on the fire resistance limit of the beam-end restrained cellular composite beam.The results are in good agreement with the finite element results and can provide reference for the fire resistance design of related projects.Based on the simplified calculation method of solid web composite beam,considering the effect of web opening,combined with the finite element analysis results,the calculation method of beam end restrained cellular composite beam axial force and displacement under high temperature is proposed,and the calculation results are in good agreement with the test results...