| Scaffold engineering plays a very important role in the safety of personnel and structure in the construction process.Wind load determines the stability and safety of scaffold,so it is of great theoretical significance and practical application value to study the wind resistance and wind vibration response of scaffold.In this paper,the object of study is steel cantilevered scaffold.Finite element modeling analysis is carried out to simulate the mechanical performance and wind vibration response of scaffold under wind load,and the results are analyzed and discussed in combination with the current scaffold codes in China.The main work contents are as follows:(1)According to the previous experimental results,the semi-rigid joint model of steel cantilever scaffold is established,and the calculation results of the model are compared with scaffold code.(2)Eight types of steel cantilevered scaffold models with different structure forms,namely,different longitudinal,span and step distances,were loaded with static wind load,and the influence of wind load and frame structure on the internal force or deformation of each part of scaffold was analyzed and discussed.(3)Taking the scaffold of Model 1 structure as the research object,the stress difference and change rule of the cantilevered scaffold at different heights are studied under the action of static wind loads of different intensities.(4)The pulsating time history wind load was simulated by software programming,and the time history wind load was loaded on eight types of steel cantilevered scaffold models with different structural forms,namely,different longitudinal,span and step distances.The wind-vibration response of the scaffold under time history wind load,including the stress of the rods and the displacements of the joints,was analyzed and discussed.Through the above research,the main conclusions are as follows:(1)By comparing the results of the semi-rigid joint model with those calculated according to the scaffold code,it is found that the effect of wind load on the stress of the rods should be considered in the calculation of the stress of the rods,while the code method does not.At the same time,it is found that the semi-rigid joint model can more accurately reflect the stress change of the scaffold caused by the change of the structure form.Therefore,the calculation results of semi-rigid joint model are closer to the actual engineering situation.(2)The maximum stress of scaffold appears at the end of large steel bar near the main joint.The minimum displacement of the connecting point of the connecting wall is 0;the stress of the large,small and upright members of the scaffold is controlled by the bending moment generated by the wind load.It is necessary to calculate the wind load moment in the design of members,so the calculation formula of the code needs to be further improved.(3)The influence of the structure form on the force of the scaffold bar is obtained,we can know that the bending moment of large bar,small bar and vertical bar is related to the longitudinal distance,span and longitudinal distance respectively.At the same time,according to the stress characteristics of the above scaffold,the construction suggestions are put forward.(4)According to the buckling analysis of the scaffold,the maximum algebraic value of the difference between the ultimate stability bearing capacity of the pole calculated by the semi-rigid joint model and the code is 45.494%,and the minimum algebraic value is-80.942%.Therefore,two methods should be used to calculate and compare the overall stability of the scaffold.(5)With the increase of the lifting position of the scaffold,the internal force and stress of the rods will increase linearly.The stress of the scaffold with low lifting height is smaller than that of the scaffold with high lifting height.Compared with the scaffold with no.IV,the stress of the rod of the scaffold with no.I is reduced by 34% at most.(6)Under the action of fluctuating wind,the bending moment of large members increases by 85%,that of most small members increases by 55%,and that of the maximum vertical member increases by 95%.Therefore,the amplification effect of windinduced vibration should be considered in the bending moment of scaffold members.(7)Under the action of time wind load,the displacement of transverse joints at the top of scaffold is the minimum of 0 at the wall parts,and the displacement of nodes between two rows of wall parts at the end of scaffold is the maximum.The displacement of scaffold vertical joints is small at the top,the largest in the middle,and the minimum displacement of the lowest joints is 0. |
