Research On The Deformation Law Of Fastener Steel Tube Full Formwork Support System And The Simplified Model Of Its Supporting Role

The fastener steel tube full formwork support system takes the main occupation of all kinds of support systems because of its convenience,high carrying capacity and versatility.However,structural failures of this system occurred frequently,due to inadequate understanding of the stress and deformation mechanism of the temporary structural system composed of the reinforced concrete structure and the formwork support system.When people made the research on the bearing capacity of reinforced concrete structures during construction,they regarded the concrete structure and the full formwork support system as a whole system,but the interaction between them was always omitted.Moreover,the method they used was very complicated.The support formwork support system was analyzed in a relative simplified way because its bearing capacity was relatively simple,which can reduce the difficulty of construction period of concrete structural reliability analysis and have important theoretical significance on study the construction period of concrete structural reliability and safety control.In this paper,the experimental research on the fastener steel tube full formwork support system was made to analyze load-deformation rules of this system by using method of theoretical analysis,experimental research and numerical simulation.In addition,based on the load-deformation laws of that system,simplified model of the carriage system was established.The research works included:(1)Make the study on the relationship between the steel tube and fastener about torque-angle and load-slip through the steel pipe-fastener torsion and sliding test and determine the appropriate constitutive model by regression analysis.Three fullformwork support systems were set up by taking consideration of lift height and spacing of upright tube to test variation law of vertical displacement and lateral displacement under vertical load and analyze influence of lift height,spacing of upright tube,load point on full frame support system load deformation curve.(2)By using established torque-rotation and load-slip constitutive relationship,the finite element models were built as same as the experimental models in order to verify its validity.Setting up some kinds of finite element models of the full formwork support system with different lift height,spacing of upright tube,bottom reinforcing tube height,adjustable forkhead,loading point to analyze the influence on the load-loading point displacement law curve.(3)On the foundation of the significance of simplified analysis,elastic support was used in order to simplify the support system.Finally,the numerical model was built by comparison of the experimental results and finite element analysis results.