The Study On Construction Technology And Application For External Prestressing In Tubes Of Cantilever Beam Structure

The project of Jiangsu science history culture center is external prestressing in tubes of cantilever beam structure. Its construction method is different to conventional construction method. This structure can build reasonable prestressing to balance partial service load, afford elastic fulcrum, advance structural stiffness and make the structure have sense of space. At the same time, this structure have complicated stress and difficult construction. Improper tensioning may result in oversize deflection and stress, and also result in crack at the end of cantilever beam. So there have necessary analysis and research to apply to construction technology of this structure.How to build prestressing in the suspension structure is a very important problem to construction. The paper computes the actual tensioning force, prestressing loss and theoretical extension value by finite procedure to comprehend structural character.Correct construction methods, reasonable construction control methods, optimization design of key node and cantilever beam have very important effect to control deflection of external prestressing in tubes. Those also can ensure safe in construction and application phase.After analyzing the character of suspension structure, using the finite element software ANSYS, the paper builds finite model of the structure and optimized key nodes. Through simulative comparison of two different construction methods, the paper also gets stress and deflection of the cantilever beam, and stress of inclined pull tube and cable. Some useful conclusions are given.On the basis, the paper proposes that prestress tensioning also needs monitoring of crack of the third cantilever beam and deflection of the end besides stress and extension value. Strengthening measure of node and cantilever beam, optimized construction methods, reasonable tensioning time, reasonable tensioning stress, prestressing loss and computational method of theoretical extension value are proposed. Construction methods of external prestressing in tubes are different from conventional pre-stressed concrete structures. Those methods must take effective measures to reduce prestressing loss and adverse effect of tensioning cantilever beam in some link. Such as anchorage setting, material cutting of steel wires, reeving cable, tensioning and so on.There are no any cracks at the end of cantilever beam by monitoring. The deflection of the lowest cantilever beam is 0.46mm<1.3mm(result of ANSYS). This shows that analysis and calculation of tensioning stress is reasonable. The finite procedure ANSYS can simulate external prestressing in tubes of...