Stability Analysis Of Prefabricated Building External Hanging Bracket

With the rapid development of China’s construction industry and the continuous maturity of technology,assembly building which is a new concept and technology has been used in more and more new construction projects.External hanging bracket which is suitable for prefabricated building is a new type of scaffolding.The hanger can achieve high production,low energy consumption and short construction period,which is conducive to promoting the construction process.However,little research has been done on the hanger at home and abroad.It is of great significance to study the hanger problems for the development of assembly architecture.The stability of the hanger is an important index to measure construction safety.Based on the basic theory of structure,this paper analyses the law of stability of the hanger.The hanger model is established by ANSYS finite element simulation software,and the overall stability law of the suspension is studied.The main research works and results are as follows:The stability of the hanger is analyzed theoretically.Firstly,the method of setting up the hanger in the window position is studied.It is concluded that the vertical bar of triangular support should be extended to the position below the windowsill which should be anchored by the wall-piercing bolt.The method of setting up the hanger in the balcony position is studied.It is concluded that the cross bar of triangular support is extended and reinforcement should be carried out.Secondly,the influence of the reliability of the bolt on the stability of the hanger is studied.The results show that the effect of the upper bolt is greater than the lower bolt.The influence of bolt anchorage through the wall on the stability of the hanger is also studied.The results show that the bolt is anchored in the cast-in-place position which is more reliable,but the concrete must reach a certain strength and delay a certain period of time.Then,the influence of unfavorable load on the stability of the hanger is studied.It is results that the edge protection is very sensitive to the horizontal wind load.Considering the horizontal seismic action,all loads at the corresponding height of the suspension should be reduced.The hanger is very sensitive to vertical load,so it should be avoided to impose vertical load for a long time during the whole construction process.Finally,The influence of failure of triangular bearing joint on the stability of the hanger is studied.It is results show that horizontal forces acting on stiffeners with triangular bearings in case of failure of transverse bars,and the welding joints of thetriangular support of the hanger must meet the welding standards.The overall finite element model of the hanger was established by ANSYS.The model was studied from the aspects of the structural size of design,disadvantageous load,component failure and structural reinforcement.The results show that the length are designed to be 800 mm and 600 mm as the vertical bar and cross bar of the triangular support of the hanger.The width of scaffold board is designed to be 600 mm,and the length should not be too long.The height of the edge protection is designed to be 1800 mm.The influence of level surface load is much greater than the vertical load to the overall stability of the hanger.Except for the support under the scaffold board,the effect of concentrated load on the scaffold board is greater than the edge protection.To the triangular support upper half of the oblique bar is the bar of the greatest influence on overall stability.For framework of the scaffold board,the width bar is the bar of the greatest influence on the overall stability.For framework of the edge protection,the vertical bar is the bar of the greatest influence on the overall stability.When the hanger has more than one bar fails,the overall displacement can be calculated by superposition of the displacement under each failure bar.The way of adding or reducing bars changes the force form of the hanger,and then changes the maximum stress.In order to improve the overall stability of the hanger,it is preferable to add the vertical bar of the edge protection.Secondly,the triangular support with diagonal brace is considered,namely,one end is welded at the triangular support and the other end is welded on the outer steel pipe of the scaffold board framework in the long direction.