Dynamic Analysis Of Scaffold Under Constructors' Walking Load

The contents of this paper are part of the National Science Foundation of China(No.51578050):" The Anti-error Mechanism and Countermeasure of the Large Template Support System".In China,the scaffold accident caused by human error frequently happened,not only caused enterprises' benefit and people's lives and property enormous loss,but also aroused widespread concern in society.In this background,this paper mainly carried out the following work:(1)According to the results of field research,two common construction operation behaviors-weight-bearing walking and hammering in the scaffold installation process were given.And the imitation experiments of these two common operation behaviors were carried out to obtain the time-history data of the simulators A and B's joint angles during weight-bearing walking and hammering.The data above were also analyzed and processed.(2)Based on the data of the behavior imitation experiments above,the 3D human body model was established.And taking the time-history data of human body's each joint angle as the initial driving data,the behavior simulation analysis of constructors'two common operation behavior on the scaffold was conducted.Consequently,The dynamic load model of simulator A and B when weight-bearing walking—F-wb load model is given in this paper.The reasonable size of scaffold is also given according to the the maximum activity range of simulator A and B.(3)According to the new dimensions of the scaffold given by the behavior simulation analysis,the finite element model of scaffold was established.And the walking dynamic load,generated by the constructor was obtained on the basis of the F-wb load model.The walking dynamic load was applied to the scaffold.Under the action of static and dynamic load,the deformation and force of the scaffold are discussed." The increase effect of dynamic load De" is defined to measure the increase of the scaffold's internal force in consideration of the dynamic effect than not.Through the calculational analysis,it can be concluded that the internal force peak of the scaffold section is higher than the maximum internal force when the dynamic effect is not taken into consideration,which is disadvantageous to the structure.Therefore,from the view of structural capacity,it's insecure to simplify the dynamic load into static load in structual desigh.The simulation analysis of the single walking load applied to different layers of scaffold was carried out to discuss the deformation and force of the scaffold.With the dynamic analysis of scaffold in two different situations,in which the two-person walking load was applied to the fifth layer adjacently and separately.The results show that:the two-person walking load can reduce the displacement of the scaffold's horizontal bars,which is conducive to the scaffold safety.While,There is no explicit reduce-effect on the internal force of the horizontal bar of the scaffold.