Study On Mechanical Performance And Reinforcement Of Opening Hole On Frame Beam

With the rapid development of our country’s construction field,people’s requirements for living comfort are continuously increasing.As an important evaluation index,indoor clearance height affects people’s intuitive experience of indoor space.For new buildings,part of the pipeline equipment can be passed through the beams to ensure the indoor clearance height and reduce the cost.According to my country’s policy reforms,the transformation of old communities is no longer demolition,but old reforms.In the process of refurbishing the old residential buildings,it is bound to encounter the situation of adding air conditioning ventilation and water,electricity and gas pipelines.Opening a hole in the beam and arranging pipelines as an implementation plan can effectively solve this problem.Opening holes in the beam will weaken its stress performance and change its damage pattern.Reinforcement measures must be taken to ensure the stability of the structure.In actual engineering,the location of the opening on the beam is random,so it is very necessary to study the influence of the opening in different sections of the frame beam on the force performance of the beam and the corresponding reinforcement.This paper mainly analyzes and studies from the two aspects of the hole of the opening in the shear bending section and the hole of the opening in the pure bending section.First,the feasibility of the finite element method is verified by comparing the finite element calculation results with the tests done by domestic scholars.For the beams with openings in the shear bending section,the mechanical properties and failure modes of frame beams with three shear span ratios of λ =0.97,λ =1.95,andλ =3.41 are studied respectively,and the best hole diameter range and vertical position of the hole are finally determined: The diameter of the opening should not be greater than 0.4 times the beam height,and the vertical position of the opening should be on the neutral axis.Then strengthen the beams with openings for these three shear span ratios.When λ =0.97,use steel plate to reinforce;when λ =1.95,use carbon fiber cloth and steel plate to reinforce;when λ =3.41,use carbon fiber cloth to reinforce,and the reinforcement effects are studied separately,which provide reference for actual engineering.Finally,for the beam with a purely curved section,the influence of different hole diameters and vertical positions on the mechanical performance of the beam is studied,and steel plate reinforcement measures are taken,the reinforcement effect is studied,and the best hole diameter range and vertical position of the hole are obtained.According to the mechanical performance and reinforcement research results of the frame beam after opening the hole,for the frame beam with opening,the diameter of the opening should be controlled within 0.4 times the beam height,and the opening position should be opened on the neutral axis or biased to the tension zone;opening with a small shear span ratio,the beams should be reinforced with glued steel plates.For beams with medium shear span ratio openings,steel plates or paste reinforcements can be selected according to the cost or construction conditions,and beams with large shear span ratio openings can be reinforced with pastes.The open beam in pure bending section is reinforced with pasted steel strips,and the effect is obvious.All reinforcement schemes can improve the mechanical performance of beams with openings to the strength of beams without openings.