预应力钢管混凝土组合结构计算理论与应用研究

The concrete-filled steel tubular structure(simplified for CFST structure) owns the many advantages such as low cost, high function, good reasonableness and construction convenience and so it is used widely in the compressive columns and bridge arches.This reseach combines organically the CFST with the prestress technigue and measurementally control to make full use of the high compressive strengh owned by the CFST and the high tensional strengh by cable.The new composite structure can be applied in the long span and/or heavy loading structures to save materials, increase the strengh and rigidity, enhance the stability, facilitate the construction and improve the durability, ect. n the basis of lots of references and research theoretically, good conclusions are drawn out with the practice of two actual projects. The main results and advances are listed below. .1)The design method and application of prestressed (tubular) composite CFST structure with hollow section.The loading test was carried out and some parameters were measured in site. The result indicates that the ratio of span to height of the beam is much greater than the ordinary steel structure and reinforced concrete structure.It has large rigidity and small deflection under the service. The construction is simple and convenient and the cost is low. Anymore, the tension force in the cable can be controlled and adjusted to certain a level according to the different needs and gaols.2)Taking the multi-storey and high-rising dwelling buildings with steel structure as the research object, the design method and behaviors of the prestressed concrete-filled steel rectangular (simplified as PCFSR) beam and arch truss with different spans are studied and applied in the experimental buiding. The upper side on the beam is open for the filling of concrete in it and aslo for the integrity with the concrete on the slab which is united with the folded steel slab on the bottom. Also the approach of connection and calculation in joints among the columns and beams, or elements are researched and analysized as well as the walls and floors. The result indicates that the ratio of height to span is only 1/33 and enough.The arch truss in the roof needs a little more height because of the drainage, but the ratio is also only 1/17. The experimental building is now in good function and service. It not only saves the materials such as steel, concrete and decreases the weight of the building, but it also facilitates the construction and economizes the cost at all. This result would provide background for the application of CFST/CFSR structure in the horizontal system.3)The layout and prestressing of cables in spacial truss are researched and discussed as well as the design and analysis in different stages. The cost is compared with other structures. The result indicates that both the mechanical behaviors and economy are excellent.4)The some behaviors of slender CFSR elements and their connection of the joints are analysized by FEM and tested.It shows that the composite compressive strengh is not improved as high as the designed, but the anti-punch strengh in the joints is increased greatly.5)On the recoginization and analysis of failure modes in different joint connection, the K-shaped joint of CFSR is analysized by ANSYS.The result shows that the cored concrete improves the anti-punch strengh of steel tube wall and the pressure could be dispersed in 45°.(the result will be prepared to be published)6)The wider application for the prestressed zspacial)steel structure and PCFST composite strcuture are reseached and narrated from the point of possible structure and span to economy.All the results would enrich the theory and practice of compound material, composite structure, long-span spacial structure and prestress technique.It certainly owns magnificent scientific and economical value for promoting prestress technique, widening the application of steel structure, and developing compound material and composite structure.

在普通钢管空间结构中，通过灌浆制成钢管混凝土结构并施加预应力，研究管径与壁厚比，钢材与混凝土强度比，节点联接方式，预应力施加方式及位置等因素对结构受力变形性能，破坏形态，极限强度和经济性的影响规律，建立预应力钢管混凝土结构体系的设计计算理论和分析方法。本项目研究对发展新型大空间组合结构和预应力技术具有重要的理论应用价值。