A Modified Calculation Method for Bearing Capacity of CHS-to-RHS T-Joints Based on Equivalent Brace Section

In order to study the bearing capacity relations between circular hollow section (CHS)-to-rectangular hollow section (RHS) T-joints and corresponding RHS joints, the refined finite element analysis models of two kinds of joints were established based on the bearing capacity test data of CHS-to-SHS T-joints, and the parameter analysis of the two types of joints was carried out. The effects of various dimensionless geometric parameters, including the ratio of brace diameter (or side length) to chord width β, the ratio of chord width to its wall thickness γ, the thickness ratio of brace to chord τ, the ratio of chord section height to width ξ, the properties of axial force in the brace, and axial force in the chord on the failure mode, stress distribution and bearing capacity of the joints were considered in the analysis, and the effects of various factors on the bearing capacity ratio of the two types of joints were obtained. The results showed that the dimensionless geometric parameters of the joints and the axial force properties of the brace had great influence on the bearing capacity of the joints, and the bearing capacity relations between the CHS-to-RHS T-joints and corresponding RHS joints were not a simple relations based on the ratio of the diameter of the circular brace to the side length of the square brace (i.e. π/4). Considering the influence of various factors on the bearing capacity ratio of CHS-to-RHS T-joints to RHS joints, a correction coefficient was proposed to calculate the bearing capacity of CHS-to-RHS T-joints based on the formula in Standard for Design of Steel Structure (GB 50017—2017), and its rationality was verified by experimental data.