ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
Membrane construction cables are all made of high-strength parallel steel cables with P sheath, with a maximum length of 110 m and a total length of 21,465 M. Glass fiber fabrics (PTFE) with polytetrafluoroethylene (PTFE) film cover are partly made of double layers. 2. Construction technology of long-span multi-unit continuous cable-membrane structure of Expo Axis 2,1. Deepening design of cable-membrane structure of Expo Axis 2,1 The main task of the design is to solve three problems: first, material selection; second, shape finding and cutting design of membrane structure; third, deepening and optimizing of components and joints; first, the selection of membrane materials not only needs to meet the mechanical properties required by the structure, but also needs to meet the architectural requirements of self-cleaning, fire prevention and durability. In this project, the PTFE film of St. Bangor Functional Plastics Co., Ltd. is used as membrane material. Firstly, the shape of the membrane structure under self-weight and prestressing state is determined, i.e. shape finding, and then the film material is cut. The cutting of membrane material needs to be designed with prestressing force. After determining the necessary parameters, the cutting of membrane material can be planned.
Deepening of membrane joints requires full consideration of membrane stress, the pattern of membrane edge and the construction effect cabinet , mast and steel cable as the supporting structure of membrane structure system. The main consideration in deepening design is to determine the position, direction and geometric size of the whole membrane structure according to the internal force of the cables, and determine the required cables according to the location, direction and geometric size of the cables. Specification and length, and according to prestressing construction technology, to determine the setting of tension structure, the optimization of the shape of e-mast and the deepening of joint construction, as well as to determine the division of mast according to the making and installation technology. Figure 4 The difficulty of multi-cable junction joints at the top of the external mast (cable-membrane structure construction technology) lies mainly in the cast steel joints at the top of the external mast. In the deepening design of points, at most 13 cables converge at one node. Deepening the design of the joint, the aesthetic appearance of the building, the optimization and strength check of the joint structure, the feasibility of casting technology, and the requirements of cable installation technology, etc. After several adjustments, it took several months to complete the structure and joint test of 2.2 cable-membrane structure. Because the cable-membrane structure of the Expo Axis is located in the important position of the central axis of the Expo Park, and has the characteristics of large scale and multi-unit continuity, it is necessary to ensure the safety and construction quality of the structure in the process of design and construction. Structural test and joint test 1 Scale test of the whole structure.
In order to test the stability and safety of the uranium cable-membrane structure of the World Expo under the condition of partial failure, the overall scale test of the structure was carried out [1:20]. The test results show that the structure can maintain overall stability under the condition of 1000 restraint failures. 2) Dual-step tensile test of membrane material. According to the requirements of the regulation yard, the strength of the membrane is generally tested only by single-step tensile test. However, in view of the fact that the membrane structure of this project is in the state of biaxial tension, the biaxial tension test of the membrane is made to test its biaxial tension. Some characteristics of the membrane material are reflected in the test, and the edge roughness structure of the membrane structure is optimized. Fifth, the biaxial tension test of the membrane material (cable-membrane structure construction technology) 3) the bonding test of the double-layer membrane material. Class A membranes with the highest strength of civil membranes are used in this project, but they still can not meet the mechanical requirements of membrane structures. Double-layer membranes are needed to reinforce the parts with high stress. Because it is the first time to adopt a large number of large-area double-layer membranes. In order to make the double-layer membranes work together and avoid wrinkles, the bonding test of the double-layer membranes and the loading test of the finished product strength of the unit membranes are carried out.
Based on the biaxial tension test of membrane material, the loading test of unit membrane (6m2) was carried out.