| The cylindrical intersecting ring pipe-cable net curtain wall was mainly composed of intersecting ring pipe skeleton and saddle-shaped monolayer cable net.8 oval ring pipes were placed at an angle with the ground as the curtain wall skeleton, intersecting each other to form 56 grids in space. The cable net was divided into 56 parts which were relatively independent, filling the 56 grids formed by the skeleton. By connecting to the podium at the bottom with the cradle, to the roof at the top with the connecting member, to the main structure at the facade with the umbrella-shaped support, the curtain wall was attached to the main structure. Such kind of structure, with large-scale, attractive appearance and other characteristics, were arranged complexly with a huge number of cables. The force in the structure were complex because the cable force impacted mutually, and this had brought considerable difficulty to design and construction.The theatre of Wanda Hanxiu in Wuhan was a large water project performance center. It was rich in traditional Chinese elements with a "Red Lattern" shape, and it excellently interpreted the characteristics of Chinese culture. The cylindrical intersecting ring pipe-cable net curtain wall perfectly created the "Red Lattern" shape. Combined with the project, this paper carried out the study on form finding and force finding methods of the cable net, structural dynamic characteristics analysis and load analysis, construction methods and construction process simulation analysis, anti-slipping performance of cable clips, and performance of the key joints. These were introduced as the following:Summarized the common forms and engineering applications of cable net structure. The cable net structure was mainly used in roof and glass curtain wall of stadiums, while it was used in the disc-type hollow curtain wall in the theatre of Wanda Hanxiu in Wuhan. It had its own uniqueness, which were different from regular horizontal cable net roof structure and also were different from enclosed glass curtain wall. This paper introduced the overview of the project and the structural characteristics of the curtain wall.Carried out a detailed study of the mothods of form finding and force finding of cable net structure. In order to find a curved surface which meet the known mechanical equilibrium in prestressed state and the structural boundary conditions, there was a need to do the form finding analysis. Theoretical studies were carried out which were about the cable unit displacement function of nonlinear finite element method, UL coordinate formulation of cable unit, the solving methods of nonlinear equilibrium equations and the specific nonlinear finite element method of form finding. A corresponding calculation procedure was worked out, in order to do the form finding analysis by using the small elastic modulus form-finding method. A cable net form which meet the predetermined equivalent pretension was found, without considering the weight of the cables and the cable clips. Also, a study of force finding was carried out from two aspects, which were the applying of equivalent pre-tension on the cable and the theory of iterative force-finding method. Also without considering the weight of the cables and the cable clips, the distribution of cable force corresponding to the result of form finding was found. Then considered the weight in this initial equilibrium state, and got the distribution of cable force in the initial state under dead load.The structural balance stiffness was solved in large deformation, and the dynamic characteristics of the structure were solved based on the stiffness in the initial state under dead load. The natural frequency of the curtain wall was intensive, and the vibration mode was mainly of local bending. The performance of the structure withstand the external loads when it was in the initial state was studied. The study was focus on the structural performance under wind load, because the cable net curtain wall had the characteristics of light weight and small stiffness which meant it was wind-sensitive structure. Although the cable net had a large deformation on serviceability limited state, it still could meet the requirements because there was no requirements of waterproof and anti-collision to the hollow curtain wall. The structural stress under the ultimate limit state was moderate, and it meant the structure was safe and economical. Under the extreme wind load, there was no significant stiffness degradation of the steel part, while the stiffness of the cable net part was increased due to the geometrical effect. In addition to wind load, the temperature effect would have some impact on the pre-tension of the prestressed cable net structure, thereby affecting the overall stiffness of the cable net. So the temperature effect was also an important function to load analysis. The results showed that the deformation caused by the temperature load of ±30 degree on the cable net was about 1/27 of the deformation caused by the wind load.Because of the large number of the cables and the highly holistic of the structure, the construction sequence had a significant impact on the project amount, construction precision and construction period. A reasonable construction sequence was determined by coordinating the objective contradictions. There was a need to do the whole construction process simulation analysis according to the construction sequence, because it could guarantee the structural safety in the construction process and provide a reference for the cable tension control.Good anti-slipping performance of the cable clips and mechanical performance of the joints were the guarantee of the structural design assume. The results of the experimental study of the anti-slipping performance of the cable clips showed that the maximum resistance to unbalance force was about 11kN. Solid finite element analysis was done to find out the mechanical performance of the key joints, and proposed targeted reinforcement measures to the joints which not meet the structural requirements.The final section summarized this paper and pointed out the main conclusions of the study, as well as the problems need to solve in the future. |
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