Experimental Study On The Reinforcement Capacity Of Cold-formed C-shaped Steel Purlin

As a new type of high efficiency profile,cold-formed thin-wall steel is widely used in industry,agriculture and civil buildings due to its light weight,high strength and simple processing equipment.Cold-formed thin-walled C-shaped steel purlins are often used as enclosures in steel structure industrial buildings to reduce the span of the roof and facilitate the laying of roof panels.Due to the limited land resources,in recent years,a number of energy companies in many places in the country added photovoltaic equipment in light steel structure industrial plant for power generation.Due to the overloading of the original workshop caused by photovoltaic equipment,C-shaped steel purlin and the original rigid frame need to be reinforced.This paper take dongfeng industrial park workshop of zhongzhou group in jiaozuo city,henan province as an example to study and discuss the reinforcement methods of C-shaped steel purlin.Based on the failure mode of the cold-formed thin-wall C-shaped steel purlin,this paper presents two different reinforcement schemes,and analyzes the concrete reinforcement effect from two aspects of experiment and finite element simulation.The detailed research contents are as follows:(1)The first reinforcement scheme is to add some connecting batten plates separated by certain space on the opening side of the cold-formed thin-wall C-shaped steel purlin.Two variables,width and spacing,were considered.Firstly,the test method was used to analyze the load-displacement curve and load-strain curve at the most dangerous section of purlin,and the degree of improvement of the ultimate bearing capacity of purlin under different reinforcement methods was discussed.Secondly,considering the influence of material nonlinearity,geometric nonlinearity and other factors,a reasonable constitutive model is selected to establish the finite element model of effective strengthened C-shaped steel purlin.The reinforcement effect of different reinforcement methods is analyzed.Finally,the experimental results are compared with the finite element results.The results show that it is effective to reinforce C-shaped steel purlin by adding connecting batten plates.The flexural rigidity and ultimate bearing capacity of the strengthened C-shaped steel purlins are obviously improved.And the strengthening effect is improved with the increase of the width of the connecting batten plate and the decrease of the distance between the batten plates.(2)The second reinforcement scheme is that two cold-formed thin-wall C-shaped steel purlins are connected by a C-shaped thin-wall steel plate to form a continuous purline.Self-tapping screws and adhesive were used for connection respectively.Firstly,the experiment was carried out,the test results was analyzed,the load-displacement curve at the most dangerous section of purlin was analyzed,and the degree of improvement of the ultimate bearing capacity of purlin under different connection modes was discussed.Secondly,the finite element calculation model is established to analyze the reinforcement effect of the strengthened post-purlin under different connection modes.Finally,the effectiveness of the reinforcement is discussed by comparing the experimental results with the finite element simulation results.The analysis results show that the overrall flexural rigidity of strengthened continuous purlin is improved greatly and the ultimate bearing capacity is also good when the adhesive is used to reinforce the C-shaped steel purlin and C-shaped thin-wall steel plate.When the self-tapping screws are used to connect the C-shaped steel purlin and C-shaped thin-wall steel plate,the position of the self-tapping screws has a great influence on the reinforcement effect of continuous purlin.