A total of 270 nonlinear steady-state finite element (FE) analyses were performed on 54 FE models of two-planar CHS KK-joints subjected to axial loading at five different temperatures (20°C, 200°C, 400°C, 550°C, and 700°C). The main objective was to study the influence of temperature and dimensionless geometrical parameters on the ultimate load, failure modes, and initial stiffness of the KK-joints. Results indicated that on an average basis, the ultimate load of a two-planar tubular KK-joint at 200°C, 400°C, 550°C, and 700°C is 90%, 75%, 45%, and 16% of the joint’s ultimate load at ambient temperature, respectively. Outcomes of the parametric study showed that replacing the yield stress at ambient temperature with the corresponding value at elevated temperature, to apply the EN 1993-1-8 equations for the calculation of the joint’s ultimate load at elevated temperatures, may lead to highly unconservative results that might endanger the safety of the structure. Results of the parametric study were then used to develop a set of design formulas, through nonlinear regression analyses, to calculate the ultimate load of two-planar tubular KK-joints subjected to axial loading at elevated temperatures.

在五种不同温度（20°C、200°C、400°C、550° °C 和 700°C）。主要目的是研究温度和无量纲几何参数对 KK 接头的极限载荷、失效模式和初始刚度的影响。结果表明，在平均基础上，200°C、400°C、550°C 和 700°C 时双平面管状 KK 接头的极限载荷分别为 90%、75%、45% 和 16%接头在环境温度下的极限载荷，分别。参数研究的结果表明，将环境温度下的屈服应力替换为高温下的相应值，应用 EN 1993-1-8 方程来计算接头在高温下的极限载荷，可能会导致可能危及结构安全的高度不保守的结果。然后，参数研究的结果被用于开发一组设计公式，通过非线性回归分析，计算在高温下承受轴向载荷的双平面管状 KK 接头的极限载荷。