Research Of Flexural Performance Of Reinforced Concrete Beam Strengthened With Double Channel Iron

Since the 21 st century,China’s first-and second-tier cities have a large number of old buildings from the 1960 s to the 1980 s.The buildings are mainly reinforced concrete structures.With the advancement of China’s building technology,people pay more and more attention to the safety,durability and seismic performance of buildings.The structure of this part of the building may not meet the bearing capacity and seismic requirements of the relevant design codes in China,but if it is demolished and reconstructed,It will cause waste of resources and does not meet the requirements of modern green environmental protection.Therefore,it is a hot research topic to reinforce the structure of old buildings.The method of reinforcing concrete beam with double channel iron belongs to outsourcing steel reinforcement method,which has the advantages of convenient construction,short construction period,less wet work on site,and combines the excellent performance of SRC structure,which can effectively improve the bearing capacity and seismic resistance of the original reinforced concrete beam.Performance,but there are many researches on the use of I-beam and angle steel reinforced concrete structures at home and abroad.There are relatively few studies on the reinforcement of reinforced concrete beams by channel steel,and more research is still needed.In this paper,the combination of experimental and finite element simulation is used to study the flexural behavior of reinforced concrete beams strengthened with double channel iron.The research results are obtained as follows:(1)Through the three-point static load test of a reinforced concrete beam and five double-sided channel steel reinforced concrete beams,the simple use of structural adhesive-bonded channel steel,the simple use of bolt-anchor channel steel,combined structural glue and bolts The influence of common anchor channel steel on the reinforcement effect of reinforced concrete beams and its failure mode are analyzed.The test results show that the test piece with structural glue adhered to the channel steel suddenly drops during the loading process,the load drops rapidly and is brittle,and the test piece which is anchored by the structural glue and the bolt is bent and damaged.There are certain signs before the damage,and the bending capacity of the original reinforced concrete beam can be greatly improved,and the reinforcing effect is better.(2)After the test,the influence of the section parameters of the channel steel and the bolt spacing on the bending performance was studied by ABAQUS finite element simulation analysis.The results show that the section parameters of the channel have a great influence on the yield load,ultimate load,ductility and failure mode.The larger the bolt spacing is,the larger the end of the channel and the reinforced concrete beam are.Slip,the more unfavorable the bending resistance,but the bolt spacing does not need to be too dense due to the sealing and bonding of the structural adhesive.(3)Based on the experimental and finite element simulation results,this paper discusses the calculation method of the normal section flexural capacity of reinforced concrete beams strengthened with double channel steel;the construction measures of the bolt end distance;the calculation method of bolt usage.