The Influence Of Position Of The Tie Member On The Mechanical Properties Of The Pole Pieces Of Scaffold System

Scaffolding is an indispensable temporary structure in the construction.The design and use of the scaffolding are related to the safety of construction workers,engineering quality,project progress and project investment.With the development of the construction industry,high-rise building,towering structure and large-span structure emerge.As the floor-mounted scaffolding erection is limited by the height and site conditions,Steel Shapes Cantilever Scaffold has already found a widespread application.However,in the use of scaffold,accidents especially like collapse happens occasionally.The reasons are not only illegal operation,technical backwardness but also experience dependence construction.As building height increases,load becomes complex,especially wind load increases rapidly,leading to the new problems in the design and construction of the hanging buckled type steel pipe scaffold.For instance,as a result of different structural forms and different sizes,we often encounter the situation when Tie Member can not be completely located in the major node.Therefore,it is necessary to study the mechanical behavior of each member of the Tie Member with the deviation of the distance from the main node of the wall member and finally put forward reasonable suggestions.In this paper,the finite element analysis of the semi-rigid joints of the actual size of the frame is carried out.The study found that the stress value of the wall member is obviously increased when the height of the scaffold is increased.However,when the height reaching 450m or above,the growth trend of Tie Member is relatively slow.Analyzing the scaffolding at the same height,we can find that the stress value in the central part of the Tie Member is greater than the one on the edge of the Tie Member.The standard formula study found that The calculated value of the code is smaller than the value of the simulated analysis of semi-rigid nodes in Tie Member.The calculation formula given provides a smaller value as well as a dangerous design.As the height of the scaffold increases,the simulated value obviously differs from the code value and the difference gradually increase.Based on the simulation curve of the proposed correction,this paper offers a specific formula,Nt = Nl1 3kN × r,the formula is given r value.In order to further study the influence of the position of the wall member on the mechanical performance of other bars,the finite element analysis and experimental study of the test model are carried out,and the conclusions are drawn from the comparative analysis.The test model is divided into two groups,each group of three specimens,test simulation of equivalent wind load standard value,in the laboratory at different heights of the equivalent wind load test.In order to study the rotational stiffness of the semi-rigid joint,the rotational stiffness is measured according to the standard test method.When the tightening torque is 50N.m,the rotational rigidity of the fastener is 38.043 kN · m/rad.The results show that under the wind load,the stress and axial force of the scaffolding frame are increased with the increase of the load,And in the elastic stage.In the case of connecting the wall member to the main node and offsetting the main node,the maximum stress value on the large cross bar with the wall member is larger than that of the large cross bar without the wall member The stress value of the outer row bar is greater than the stress value of the inner row bar at the node with the wall member;the stress value of the inner row bar member at the node without the wall member is greater than the stress value of the out row bar member,Even if the displacement of the wall of the main node of the wall than the case of the main pieces of the wall,along the direction of the deflection of the large cross-bar stress value increases,away from the direction of the big bar of the stress value decreases,After moving the main node,the axial force value of the connected wall member which is far away from the direction is increased,and the concrete numerical values are given.Therefore,the safety design of the scaffolding will consider the adverse influence of the displacement of the wall element on the master node.It is hoped that the results of this paper can provide references for the related design.