Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
A new type of segment assembled joint for curved reticulated shell structure is proposed. The joint consists of three parts: segment sub-member, central area rib plate and high strength bolt. Different from traditional welding joints, the main components of this joint are prefabricated by the factory and assembled by high-strength bolts on site, which not only reduces the welding workload, but also avoids high-altitude welding, reducing the difficulty and risk of construction. In addition, the center area of the node is connected without cover plate, which fully reflects its semi-rigid characteristics and is also convenient for later maintenance. In order to explore the mechanical characteristics of the joint, the static comparison test of assembled joint specimen and welded joint specimen was designed and completed. For 6 full-size specimens of two types of joints, the test adopts three loading methods: axial, eccentric and transverse compression. The strain distribution law, load-displacement curve, moment-angle curve and failure mode of each key part of the two types of joints are compared and analyzed. The unidirectional compression and bending performance of the assembled joints are investigated, and the weak parts and the influence of bias pressure are obtained. The evolution of the mechanical characteristics of each joint under unidirectional compression and bending is analyzed by finite element method and compared with the experimental results. Through the test and finite element analysis of the fan-shaped assembled joints and the traditional welded joints, the following conclusions can be obtained: under unidirectional compression load, the fan-shaped assembled joints show the same performance as the welded joints, that is, the force is reliable and the deformation is small; In the whole loading process, the axial stiffness of the sector assembled joints is very close to that of the welded joints. Under axial eccentric load, the axial stiffness of segment assembled joints decreases obviously, so the effect of compression and bending combination on joints should be considered in practical engineering application. In the bending test, there are three stages in the failure process of segment assembly joints :1) elastic stage. When the bending moment is less than 81.5 kN·m, the joints show good bending resistance. 2) Elastic-plastic stage. When the bending moment is 81.5~142.6 kN·m, the bending stiffness has obvious degradation. 3) Plastic failure stage. When the bending moment is greater than 143 kN·m, the high-strength bolt is brittle and the specimen is damaged. Therefore, the key to improve the flexural stiffness of this joint is to improve the shear resistance of the bolt. The final failure mode of the fan-shaped joint is consistent with that of the test, and the stress distribution and the moment-angle curve have a high coincidence.
