| With the rapid development of China's economy,the engineering projects of super-large construction have been applied widly in our country.Because of the disadvantages of the structures such as complicated form of structure,difficult of construction and so on,the require of afety requirements of temporary structures is more and more extensive in the construction process.Scaffolding is an indispensable temporary structure in the construction process.The development of its design theory and construction technology has attracted much attention.The Ministry of Housing and Urban-Rural Development has listed the"template and scaffolding technology"as one of the 10 new technologies that the construction industry will promote in the 2010 and 2017 editions.From 2017 to 2019,the scaffolding project was listed by the Ministry of Housing and Urban-Rural Development as one of the five most dangerous sub-projects with major rectification in the industry for three consecutive years.As the increases of the height of building structure,the influence of wind loads on the structure becomes more significant,and the control load of the structure design gradually changes from vertical load to horizontal load.However,the current design and construction standards and specifications for temporary structures such as scaffolding and formwork in China are based on the low-altitude wind load theory within 100m from the ground.For body structures with heights more than 100m,there is little written description of wind load effects and values.This paper studies the wind load value,stability and ultimate bearing capacity of the scaffolding frame with a height of 150m?450m from the ground.First,it summarizes the research method of wind load and proposes the design of super high-rise scaffolding.In the calculation of the wind load,the calculation methods of various calculation coefficients are established;a"simplified"design theory based on wind load coefficients of wind loads is established,and the scaffold horizontal wind loads are summarized for the four types of ground roughness of A,B,C,and D And vertical wind load application data sheets.Secondly,by adjusting the basic assumptions in modeling and the way in which fastener connection nodes are embodied in the finite element,the method of establishing the finite element model of the scaffold was verified by the finite element and experiments,and the super high-level suspension was established using the finite element ANSYS software.The finite element model of the scaffold with different vertical and horizontal distances of the pole.It is clear that the wind load will have an additional axial force value on the vertical pole at the bottom of the frame.Under different installation methods,the minimum increase of the axial force of the vertical pole exceeds the calculated value.10%.It is suggested that for the super high-rise scaffolds with a base level above 150m,the additional axial force effect of the wind load on the bottom pole should be considered,and a new calculation formula is proposed:N(?).At the same time,this paper uses finite element analysis to further explore the effect of wind load on the ultimate bearing capacity of the scaffold,and obtains the change of the ultimate bearing capacity of the scaffold with the height of the frame body.The influence of the deflection of the high-rise cantilever scaffolding frame,through the increase of the horizontal diagonal brace and the vertical diagonal brace,four kinds of optimal structural measures to meet the stiffness deformation of the frame under the arrangement of the wall parts are obtained,and the optimal The word diagonal brace layout table supplements the structural measures not specified in the relevant code.Finally,based on the"simplified"design theory of combined wind load,this article guides the construction of a large-span cantilever construction platform for super high-rise buildings in Shenyang"BN-T3 Project";through mechanical analysis,the scheme selection and the optimal structure design. |
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