Study On The Mechanical Behavior Of The Fabricated Lattice Column Formwork Support

The fabricated lattice template scaffold is a new kind of scaffold system that combines with the characteristics of the construction.It forms a lattice column by means of every two layers of framework components by perpendicular setting.Then,using the cross braces to connect the fabricated lattices to make it as a whole.This new kind of template scaffold has no complicated production process and easily makes a large number of production in a short time.Because it has differences from other template scaffolds in the physical dimension,material specification and the method of setting up,it’s necessary to prove this new template scaffold has excellent working performance and is safe enough for using in the engineering application.In this thesis,using the experiments and finite element simulation to gain bearing capacity,internal forces distribution,buckling deformation of the new template scaffold,the main research work is as follows:(1)Firstly,designing four groups of experiment to analyze the influence on the joint stiffness caused by the connecting rod’s different lengths(4cm、8cm、12cm)that stretches into standing bar and whether the rod welded with the standing bar.Using the data obtained from the experimental to analyze the joint’s relationship curve of bending moment – rotation,which will help to get the initial rotational stiffness of the joint under different conditions.The results show that the factor whether the connecting rod welded with the standing bar has influence on its initial rotational stiffness,it raised 11% when the connecting rod was welded.Furthermore,the result shows that the length of connecting rod that stretch into the standing bar was 4cm,the joint’s stiffness is 7350 N·m/rad,when the length reach at 8cm,the stiffness improve 104%,but when it reach at 12 cm,the stiffness improve 92.5%.It shows that the length of connecting rod that stretch into the standing bar created significant influence on the stiffness of joint in a certain range of 8cm,but it will out of action when the length exceeds 8 cm.(2)Designing two kinds of schemes,a total of six groups as a whole unit to do the vertical destructive test to understand the mechanical properties,such as failure mode,the internal force in the process of stress changing,ultimate bearing capacity and so on.Arranging the strain gages on the cross support,diagonal rod and cross-bar to analyze those components’ distribution in the process of load application.The results show that the new template scaffold has a good characteristics on the mechanical performance,which can handle larger vertical load than other kinds.Meantime,the cross supports setting on the scaffold can obviously improve the ultimate bearing capacity of the template framework,but the diagonal rod and cross-bar has little deformation in the process of load application which means that they almost do on effect on the mechanical properties of the structure.(3)Establishing the finite element analysis model by the software of ABAQUS to verify the correctness of the finite element model combined with experimental results.Then,considering the standing bar’s wall thickness and height,initial imperfection,rotation stiffness of joint and so on,that may effect on the mechanical properties.Combined the experiment with the finite element simulation result to provide a reference for engineering application.