Theoretical And Experimental Studies On Ultimate Strength Of Tubular Joints Applied For Long-span Steel Towers

Presently, the majority of tubular joints in long-span steel transmission towers are gusset joints and unstiffened joints. And general forms of joints are K-joints and TY-joints. As to the gusset connection joints, however, the computation of ultimate strength has not been mentioned in current PRC codes. It's also necessary to study further on the strength character of stiffened joints.Based on the project of YaMen long-span transmission tower, several reduced scale tubular K-joints and TY-joints are tested and finite element models are analyzed too. The reliability of design are verified, and the feasibility of finite element methods instead of experiments is testified. Furthermore, it is indicated that there's distinctly stress concentration for some areas of joints , which should be considered seriously in design. Some useful advices for design are also presented.According to the research above, finite element models of gusset K-joints and stiffened K-joints are established. Through nonlinear finite element methods, the failure mechanism and the ultimate strength of such joints are studied.The failure mechanism and two typical destruct modes are discovered through the research on the strength capacity and the plastic range of gusset K-joints. The relationship between the ultimate strength and geometric parameters is investigated, so as to contribute to further study.With regard to stiffened and unstiffend K-joints, the comparison for the two joints on the mechanical behavior and the ultimate strength is carried out, and some useful results are obtained.