Study on bearing capacity of multiplanar column joints in steel tubular frame
Li Zhengliang1,2 Hu Hao1,2,3 Huang Haibin1,2 Liu Hongjun1,2 Xing Haijun4
1. Chongqing University, Chongqing 400045, China;
2. Key Laboratory of New Technology for Construction of Cities in Mountain Area of the Ministry of Education, Chongqing University, Chongqing 400045, China;
3. Chongqing University of Arts and Sciences, Chongqing 400045, China;
4. China Electric Power Research Institute, Beijing 100055, China
Abstract：The ultimate capacity of a new type multiplanar tubular column joints were investigated via test under static loading and theory analysis, with the background of 750kV transmission tower engineering. Two full-scale test specimens, test instrument of self-balancing frame with sufficient stiffness and test scheme of active and passive load were presented in detail. Failure mode, load-strain curve, and mechanical performance of the experimental joints were obtained through analyzing the test results. Based on the experimental results, the theory analysis model was established and the calculation formulas of the ultimate strength of space joints determined were given by the principle of virtual work and the ring-generator separation model. The research indicates that the concave deformation occurs in the main pipes with no failure in branch ones or welds. In addition, the development of plastic hinges with local yield theoretical model can be accurately reflected and the complex stress state can be simplified considering the interaction of space branches. Compared with the experimental and finite element analysis results, the calculated ones are reasonable and the theoretical model has applicability.
