Theoretical Analysis On Main Steel Structure Of Tianjin Library And Study On Important Joints

As a new form of structure system, concrete - filled steel structure has shown broad development prospects with good mechanical properties and structural applicability. Bases on Tianjin library project, this article carries out studies on the behavior of the main structure and important joints, to provide theoretical support for the actual design and construction, and design and research experience as references for similar projects in the future.The general development and application situations of steel frame-supporting system,tube-truss structure system and concrete-filled steel tubular joints are introduced at the beginning. Then the engineering background of the subject is described, followed with the main research content.Tianjin library possesses a unique architectural structure with a complex load transmission. The main structure adopts a complex steel structure system as a combination of steel frame-supporting system and intersected trusses, and the structural design is finished. A series of Finite Element Analysises are conducted to research the mechanical performances of this structure as follows: the static,seismic and stable performances of the main steel structure and local cantilever structures; the comfort of the cantilevering corridor, etc, to ensure good bearing capacity and normal use of the main structure.According to the force characteristics of the main steel structure, type selection and design of joints are accomplished. The main types contain Baffle through joints,vertical stiffener joints,cast steel joints,welded joints for trusses and so on. Finite Element Analysises of typical joints are performed to evaluate their mechanical properties.Two representative forms of cast steel joints are selected, and the theoretical analysis and experimental study of their mechanical properties are complimented. By comparative analysis of theoretical and experimental studies, the bearing capacity of cast joints under design loads are guaranteed, the rationality of both methods of theoretical analysis and experimental study is proved. Finally, the performances of the main steel structure during the load converting process in construction is studied with Finite Element Analysis. By contrasting local monitoring results and theoretical results of structure stress and deformation, the strength and stiffness level of the main steel structure are estimated, to support load converting scheme, and to ensure a successful construction period as well.