Study On Effect Of Lateral Restraint On Mechanical Performance Of Unbonded Post-Tensioned Prestressed Floors In Frame-Core Tube Structure

The traditional compute method in the design of prestressed structure is based on the suppose that the axial tensive and compressive stiffness is infinite, unconsidering whether the transfer of prestressing force and results In fact, most indeterminate structures are lateral-limited , and some of them are very obvious (such as the frame column shear wall and core tubes in the frame-core tube structures ). these members will restrain the axial displacement of beam or flat and so have an effect on the transfer of pre-stressed force in the horizontal bended members.Based on an engineering project about unbonded prestressed floors in the frame-core tube structure in this paper, the effects that lateral restraints have on the mechanical performances of prstressed slabs are simply discussed.The finite element method is applied to prestressed slabs, the mechanical characters under the normal using load condition are analysised, with unconsidering the lateral restraints. Based on the above analysis, the effect of such two support kinds as flat-beam and hidden-beam on the mechanical performance of prestressed slabs are analyzed .By using equivalent beam imitate the bays slab that the paper cared, the vertical plane model are established,the distributional principle of secondary axial force in each floor and the influenceof different construction methods on the prestressed compressive force are analyzed.Based on the established above analysis,the whole model are constructed to imitate the lateral restraint influence, the mechanical characters under vertical load in those influencable slabs are analyzed.At last, by comparing the stress distribution and deflection character with plane model and whole model, the influence of lateral restraints on the mechanical performances under normal using load in the slabs are discussed.