Application Of External Prestressing In Replacing Of Frame Column

The safety and reliability of structure is the key to meet its design function.Due to the rapid development of national economy and the construction,all kinds of architecture was built.After decades of construction,some structure is aging.And construction units with different qualities emerge endlessly,there are more and more problems in the process of construction.Consequently,maintenance and reinforcement are increasingly important and cause great attention.Compared with the traditional strengthening methods,external prestressed strengthening technique has many advantages.Focused on building structure reinforcement,External prestressing technique can save resources and create economic value.So its prospect of use is very bright.According to the study of external prestressing technology at home and abroad,this paper summarized the design and construction of externally prestressed technology in frame structure reinforcement.According to the characteristics of the frame column structure,through the theoretical research and numerical calculation method,this paper discussed the effect of external prestressed tendons on the reinforced structure in the process of replacing column by lifting beam.Some mature construction methods were summarized and a corresponding engineering case was introduced in this paper.Through an engineering example,calculation of beam replacement by external prestressed tendons was illustrated.The corresponding reinforcement scheme and results analysis was given by the example,thus it can benefit the application of external prestress technology in the replacement project of structure.The main contents of this paper includes:(1)The basic principle and anchorage system of external prestressing;(2)Selection of external prestressed tendons material;(3)structure calculation of repalcing column by supporting beam with external prestressed tendons;(4)design and anchorage of external prestressed tendons in project example;(5)construction method of repalcing column by supporting beam with external prestressed tendons.This paper through the research will elaborate the externally prestressed pull beam technology in the column support for application of stress analysis,reinforced concrete beam is by external prestressing to the original beam applied a balanced system of force,original beams a group of self balance,offset the influence of part load,high bearing capacity.When unloading,the unloading point of the column is broken when the unloading point has a larger downward displacement,which is significant to the additional bending moment and the shear effect of the beam.According to the actual construction and site factors,the external prestressing strand is preferred to select the non bonded steel strand,the setting of the anchoring system should be firm and reliable,and the influence of the surrounding environment should be considered in the design process.