Study On Mechanical Properties Of Assembled Building Attached Jacking Scaffold

The attached jacking scaffold for prefabricated buildings(hereinafter referred to as“scaffold”)is a new type of scaffold developed according to the characteristics and construction technology of prefabricated buildings.Compared with ordinary scaffold and ordinary attached scaffold,it has the advantages of saving materials,high construction efficiency,convenient assembly and disassembly,and clean appearance.The frame can better assist the construction of prefabricated buildings and provide a strong guarantee for promoting the reform of building industrialization.In recent years,frequent accidents scaffolding,contrary to the“safe production”slogan.Therefore,in order to verify the safety of the newly developed frame,this thesis studies the mechanical properties of the two types of frames and three matching wall supports by means of experimental method and computational simulation method,and optimizes the weak points of the frame structure.Based on the relevant research on the frame,this thesis draws the following conclusions:(1)Through the test can be seen that the normal operation of the frame,the frame operation does not appear hydraulic cylinder out of the cylinder is not synchronized phenomenon,did not find the phenomenon of hydraulic cylinder leakage.However,in test 1,it can be seen that there is a gap between the back plate of the wall bearing 1 and the channel steel cantilever beam when the live load of the frame exceeds 3k N/m~2.After research,it is due to the single bolt connection between the wall bearing 1 and the channel steel cantilever beam.Therefore,the wall bearing and the attached structure connection should be double bolts and multi-bolt connection.(2)It can be seen from the test that the stress of each measuring point of the frame meets the design requirements of material strength whether it is in use or jacking condition.The anti-falling test was carried out on the frame with 6m span under 1 and 2step loading conditions.After testing,the anti-falling performance of the wall bearing is good,and the frame can be braked in time to stop the fall.After the test,the frame and wall bearing were checked,and no abnormal phenomenon was found.It shows that the mechanical properties of the frame are well designed,and the impact resistance of the guide rail and the wall support is excellent.(3)By comparing the test and calculation results,it can be seen that the calculated value of the frame is not much different from the test value of the frame,which can verify the accuracy of the finite element model of the frame.(4)Through further calculation and analysis of the verified frame,it is concluded that the maximum stress of the frame under no wind load occurs at the horizontal truss,and the maximum stress of the frame under wind load occurs at the keel of the footplate.The vertical load plays a leading role in the bearing capacity of the frame without wind load,and the horizontal wind load plays a leading role in the bearing capacity of the frame with wind load.Under the working condition of 200m height and 3k N/m2construction live load,the maximum stress of the two frames exceeds the design strength value of the material,but does not exceed the yield strength value of the material.Under this working condition,the frame body needs to be strengthened,and the aisle plate needs to be strengthened and optimized.By changing the cross-section size of the keel of the scaffold,the maximum stress of the frame body can be reduced to meet the design strength value of the material.(5)Through calculation,it is found that the stress concentration phenomenon is very easy to occur at the corners of the sliding groove of the pin shaft of the wall bearing.The stress concentration at the corners can cause the deformation and failure or cracks at the corners in advance,which affects the safety of the structure,and the stress at the stress concentration position exceeds the material design strength value.The rounded corner treatment can avoid the above problems and reduce the maximum stress,so that the bearing can meet the material strength requirements,and the stress concentration can be transferred to a relatively safe structure plane.(6)Through the stability study can be concluded that the stability of the two frames meet the design requirements.The step distance of the frame has a great influence on the stability of the frame.(7)Through the overall analysis and comparison,it can be seen that the assembled building attached lifting scaffold has the advantages of saving material,high efficiency,good safety,neat appearance,good economy and good applicability.