Finite Element Analysis Of Cylindrical Bonded-Steel-Sleeve Underpinning Joint

For most buildings with incline,as long as their integrity and main structure are not seriously affected,it is an effective way to solve the problem by lifting the structure.The design and construction of the underpinning system is the key to ensure the safety of the lifting and rectifying project.In the past,various types of under:pinning joints for frame columns were mostly applied to square columns,and reinforced concrete underpinning joints were generally used.Recently,the circular frame columns need to be underpinned in a lifting and rectifying project in Kunming,and a new type of steel structure underpinning joint,which is called Bonded-Steel-Slee-ve Underpinning Joint,was adopted for columns’underpinning system.In this paper,the ABAQUS is used to model the new type of underpinning joint,and the mechanical property of the bonded-steel-sleeve underpinning joint is obtained through numerical simulation analysis and comparative study.The following work have been done in this thesis.The structural form and approximate working mechanism of the bonded-steel-sleeve underpinning joint are given in the thesis.The joint components include steel sleeve,structural adhesive,hoop,planting rebar and I-beam.This underpinning joint is at a clear working condition and cost low.The construction process of the steel structure is simple,and its construction period is shorter than that of the reinforced concrete.So it is suitable for underpinning the circular frame column in the multi-storey building.Through ABAQUS,the stress state of each component of the underpinning joint under actual jacking conditions and supporting conditions is simulated,and the maximum bearing capacity and final jacking loss are obtained.The key to affect the bearing capacity of the bonded-steel-sleeve underpinning joint is the shear capacity of the I-beam web.Parametric analysis of bonded-steel-sleeve underpinning joint to study the factors affecting the stress state,stiffness and bearing capacity of the underpinning joint.These factors include the number of rows of implants,the radial dimension of the hoop,the thickness of the hoop and the number and manner of stiffeners.Based on these analyses,author referred to specifications related to the underpinning joint and given the calculation formulas and construction requirements of these components.The form of the bonded-steel-sleeve underpinning joint draws on the structure of the outer ring-reinforced joint of the concrete-filled steel tube.The structural adhesive and the planting rebars are used to connect the underpinning structure to the frame column firmly,and the rigidity and integrity of the underpinning joint are strengthened by the hoop.Under the conditions of underpinning,it shows good underpinning performance.So the bonded-steel-sleeve underpinning joint can be provided reference for similar projects in the future.