Research On Prestress Of The Prestressed Steel Stayed Columns

A prestressed steel stayed column is a structural component that is reinforced by stays and rods such that its strength is increased in axial compression, it is one of the basic components of prestressed steel structure. The prestress in the stays determine the stable loading capacity of the prestressed steel stayed column, although the prestressed steel structure has developed rapidly in the past few years, the prestress has been the least studied. This dissertation studies of the value of the prestress, not only gives the formula,but also analysis the parameters. Then, buckling and post-buckling and initial geometric imperfection sensitivity are analyzed by using SAP2000. The main works are:1. Symmetric and anti-symmetric buckling are analyzed. The prestress in the stays is divided into three zones according to its value. Different formulas are given in these three zones. Theoretical results of the optimum prestress and the maximum critical buckling load which are calculated by the formulas using different composition sinusoidal are contrasted. Parameters which influence the optimum prestress are also analyzed.2. Post-buckling and initial geometric imperfection sensitivity are analyzed for prestressed steel stayed columns which have different prestress.3. Because the maximum critical buckling load of the asymmetric buckling is the lowest of the three buckling modes in some cases,the dissertation derive the formula of prestress which is adequate for all buckling modes and give the design recommendations finally.The research results have shown that:The number of the sinusoidal can be selected as the same as the internode number N and the theoretical results agree well with the results of SAP2000.The post-buckling response of the column is unstable when the optimum prestress is taken and it shows great sensibility to the initial geometric imperfection, but when a larger prestress is taken; the column has a stable post-buckling response and is insensitive to the initial geometric imperfection. Considering greater prestress will diminish the magnitude of the critical buckling load, so prestress which is slightly larger than the optimum prestress would be the best in practical engineering.