Study On Mechanical Behaviors Of Assembled Wedge Steel Set On RC Cylinder Under Vertical Load

The reinforcement and reconstruction of existing engineering structures have become the focus of Civil Engineering,and the connection of nodes is the key to reinforcement and reconstruction.It is very important for the rationality and safety of the design.At present,there are few researches on the supporting joints in the building or bridge construction,and the problem of the beam-column joints in the interlayer reconstruction.When the joint design is unreasonable,it will inevitably lead to problems,long duration,construction waste and other trouble.In order to explore a joint of more convenient and reusable,a new type of assembled wedge steel set on RC cylinder has been put forward in this paper,which can be set as a fulcrum on the circular concrete columns.It can be used as the temporary support of the column during the jacking-up as well as the connection node of the new steel beam and the original column in the interior storey adding transformation.This paper focus on the structural performance of this new type of the assembled wedge steel set on RC cylinder under vertical load.First of all,the ABAQUS finite element software is used to simulate the performance of assembled wedge steel set on RC cylinder.The results show that this kind of joint has good stiffness and the ability to transfer the vertical load.The elastic stiffness and ultimate bearing capacity of the joint decreases with the decrease of the node inclination.Secondly,based on the finite element results,four specimens of assembled wedge steel set on RC cylinder were designed and tested under vertical load.The experiment mainly studies the mechanical properties of the joints and the influence of its inclination on the vertical load transfer capacity.The results indicate that the stress distribution along the circumferential direction of the hoop is inhomogeneous.Under the condition that the other parameters are invariable,the elastic stiffness and bearing capacity of the joints are improved with the increase of the wedge angle.The wedge steel set has good rigidity and the ability to transfer the vertical load.It has good stability and reliability,so long as the design is reasonable,it can meet the requirements of practical engineering.Then,comparing the finite element analysis results with the test results from several aspects,such as the load displacement curves,bearing capacity,stiffness and the deformation,to verify the rationality of the finite element model.Based on the finite element analysis model,the three key influencing parameters,such as the thickness of the stiffener,the number of stiffeners and the thickness of the hoop,are simulated and compared.The results show that the greater the number of stiffeners,the greater the elastic stiffness.The change of the thickness of the stiffener and the hoop has little effect on the initial stiffness of the joint.The increase of the thickness of the stiffener,the number of stiffeners and the thickness of the hoop will increase the ultimate bearing capacity of the joint.Finally,based on the above research results and theoretical analysis,the calculation formula of the elastic stiffness of the assembled wedge steel set on RC cylinder under vertical load has been put forward,and the value of relevant parameters is given.the vertical bearing capacity calculation formula of the assembled wedge steel set on RC cylinder has also been obtained according to the displacement as the control parameter.The comparison between the calculated values,the experimental results and the finite element simulation analysis results shows that the design formula presented in this paper has a high accuracy in a certain range,which can be used to guide similar projects in the future.