Research And Verification Of The Project Of Down-supporting Super-long Cantilever Supporting Scaffolding At The Corners Of High-rise Buildings

With the development of the country’s social economy and the rapid development of the construction industry,people’s requirements for high-rise buildings are not limited to the safety of the structure,and the aesthetic requirements for their appearance are gradually increasing,at the same time,the vigorous development of the construction industry has promoted the rapid development of overhanging structures and special-shaped structures.In the process of high-rise building construction,the completion of various special-shaped cantilever constructions often requires high scaffolding.It is necessary to erect scaffolds with high height or long supporting structure,the cantilever supporting scaffolding is widely used in the erection of high-rise super-long cantilevered structures because it saves materials,is convenient to erect,and has good economic benefits.This article takes the super-long cantilever support scaffold as the research object,takes a project in Chengdu as the background,combines literature summary,theoretical calculation,model test monitoring,finite element numerical simulation,and analyzes the cantilever support scaffold,the main research content and research results are as follows:(1)Analyze and sort out the major scaffolding accidents that have occurred in recent years,and summarize the causes of the accidents through literature review: the quality of the scaffolding fasteners is poor,the construction personnel are not standardly erected,and the on-site management personnel are not aware of construction safety;The supporting structure of the cantilever support scaffold adopts the cantilever type.Through ten sets of 1:10 physical model tests with the position of the diagonal support point as a variable,a more suitable diagonal support point position is determined.The test results show that when the angle between the lower brace and the horizontal plane is between 45° and 55°,the force of the cantilever I-beam is relatively uniform,and the concrete at the anchor point is compressed.(2)Aiming at the problem of erecting the cantilever supporting scaffold at the corner of the super-long cantilevered structure of the high-rise building with the inclined roof of the project,the erection plan was proposed,and a 1:10 physical model test was designed based on this.Analyze the stress concentration points on the cantilevered steel beams,the connections of anchor points,the stress-strain law at the local concentrated stress points,and the deformation of the free ends of the cantilevered steel beams under the action of grading loads through hierarchical loading,so as to verify whether the scaffolding erection plan meets the verification requirements.(3)Using ANSYS finite element software to perform three-dimensional numerical simulation of the prototype structure,comparing the strain and free end deflection of the finite element analysis of the I-beam cantilever beam with the test results shows that the deformation curves of the components in the numerical simulation and the model test are basically the same,and the large deformation positions appear at the diagonal brace points and anchor points.At the same time,according to the analysis of the strength,deflection and overall stability of the cantilevered steel beam,the erection plan meets the requirements of the check calculation.(4)Exploring the changing trend of out-of-plane stability and in-plane stability of the structure through continuous loading with a design loading stage of 20% of the design value and a load step of 25 steps,When the load is between 1.0 times and 2.4 times of the load design value,the stability coefficients of the two increase crosswise.When it exceeds 2 times or the stability coefficient approaches 1,the failure of the entire structure is completely determined by the out-of-plane stability.Through MATLAB language programming,the force calculation of the I-beam supporting structure of the cantilever supporting scaffold with a long overhang length is realized,and the mechanics checking calculation is carried out;the calculation results of the finite element software modeling and the GUI interface are compared,and the error of the calculation program is explored.