This paper describes a test program on the stress concentration factors (SCFs) of stainless steel hybrid tubular (SSHT) joints with square hollow section (SHS) braces and circular hollow section (CHS) chord and SSHT joints with CHS braces and SHS chord. The load was applied to the brace for all test specimens. Twenty specimens in total, including ten overlapped and ten gapped tubular K-joints, were tested. Different geometric parameters were used which include brace width-to-chord diameter ratio (β₁ = b₁/d₀), brace-to-chord thickness ratio (τ₁ = t₁/t₀) and chord diameter-to-thickness ratio (2γ₁ = d₀/t₀) for SHS-to-CHS hybrid tubular joints, brace diameter-to-chord width ratio (β₂ = d₁/b₀), brace-to-chord thickness ratio (τ₂ = t₁/t₀) and chord width-to-thickness ratio (2γ₂ = b₀/t₀) for CHS-to-SHS hybrid tubular joints. A number of strain gauges were used at the hot spot locations for various tubular joints. The hot spot stress (HSS) method was used to determine the SCFs of SSHT joints using the quadratic extrapolation method. This was a consequence of the stress distributions around the intersection area of SHS-to-CHS and CHS-to-SHS hybrid tubular joints being nonlinear. Results found the maximum SCFs for hybrid overlapped tubular K-joints with square braces and circular chord to be located at the hot spot location at an angle of 135° between the SHS brace and the CHS chord. This is characterized as line A. The maximum SCFs of hybrid gapped tubular K-joints with square braces and circular chord were located at the hot spot location at an angle of 45° between the SHS tension brace and the CHS chord (characterized as line C) and at an angle of 45° between the SHS compression brace and the CHS chord (characterized as line E). The maximum SCFs of hybrid overlapped tubular K-joints with circular braces and square chord were located at the hot spot location at an angle of 180° to the CHS brace. The maximum SCFs of hybrid gapped tubular K-joints with circular braces and square chord were located generally at the hot spot location at an angle of 0° to the CHS brace. Test results were compared against the design predictions in accordance with the current design guidelines of the International Committee for the Development and Study of Tubular Structures (CIDECT, 2001). Upon comparison, it was found that the design formulas of CIDECT (2001) overestimate the maximum SCFs of SHS-to-CHS hybrid gapped tubular K-joints. For the CHS chord and SHS braces of hybrid overlapped tubular K-joints, the design formulas overestimate the maximum SCFs for most of the specimens. Furthermore, for the SHS chord and CHS braces of hybrid gapped tubular K-joints, the design formulas of CIDECT (2001) overestimate the maximum SCFs. For the SHS chord and CHS braces of hybrid overlapped tubular K-joints, the CIDECT (2001) design formulas were unconservative when determining the maximum SCFs of such joints.

本文描述了一种测试程序，该程序针对具有方形空心截面（SHS）支撑和圆形空心截面（CHS）弦的不锈钢混合管状（SSHT）接头以及带有CHS支撑和SHS弦的SSHT接头的应力集中因子（SCF）。将载荷施加到所有测试样品的支架上。测试了总共20个样品，包括10个重叠的和10个带间隙的管状K型接头。使用不同的几何参数，其中包括支架宽度与弦直径比（β ₁  =  b ₁ / d ₀），杆条-弦厚比（τ ₁  = 吨₁ /吨₀）和弦直径与厚度比（2γ₁  =  d ₀ /吨₀）为SHS-到-CHS组合管接头，支架直径与弦宽比（β ₂  =  ð ₁ / b ₀），杆条-弦厚度比（τ ₂  = 吨₁ /吨₀）和和弦宽度与厚度比（2 γ ₂  =  b ₀ /吨₀）用于CHS到SHS混合管状接头。在热点位置，许多应变仪用于各种管状接头。热点应力（HSS）方法用于二次外推法确定SSHT接头的SCF。这是由于SHS到CHS和CHS到SHS混合管状接头的交点附近的应力分布是非线性的。结果发现，带有方括号和圆弦的混合重叠管状K型接头的最大SCF位于热点位置，SHS括号与CHS弦之间的夹角为135°。这被描述为线A。带有方括号和圆弦的混合气隙式管状K接头的最大SCF位于热点位置，SHS张力支架和CHS弦之间的夹角为45°（特征为C线），夹角为45° SHS压缩撑杆和CHS和弦之间的°（特征为E行）。带有圆括号和方弦的混合重叠管状K型接头的最大SCF位于热点位置，与CHS括号成180°角。具有圆括号和方弦的混合间隙管状K型接头的最大SCF通常位于热点位置，与CHS支柱成0°角。根据国际管状结构开发和研究委员会（CIDECT，2001）的当前设计指南，将测试结果与设计预测进行了比较。经过比较，发现CIDECT（2001）的设计公式高估了SHS-CHS混合有隙管状K型接头的最大SCF。对于混合重叠的管状K型接头的CHS弦和SHS支撑，设计公式高估了大多数标本的最大SCF。此外，对于混合间隙管状K型接头的SHS弦和CHS支撑，CIDECT（2001）的设计公式高估了最大SCF。对于混合重叠的管状K型接头的SHS弦和CHS牙套，当确定此类接头的最大SCF时，CIDECT（2001）设计公式并不保守。结果发现，CIDECT（2001）的设计公式高估了SHS-CHS混合带隙管状K接头的最大SCF。对于混合重叠的管状K型接头的CHS弦和SHS支撑，设计公式高估了大多数标本的最大SCF。此外，对于混合间隙管状K型接头的SHS弦和CHS支撑，CIDECT（2001）的设计公式高估了最大SCF。对于混合重叠的管状K型接头的SHS弦和CHS牙套，当确定此类接头的最大SCF时，CIDECT（2001）设计公式并不保守。结果发现，CIDECT（2001）的设计公式高估了SHS到CHS混合带隙管状K接头的最大SCF。对于混合重叠的管状K型接头的CHS弦和SHS支撑，设计公式高估了大多数标本的最大SCF。此外，对于混合间隙管状K型接头的SHS弦和CHS支撑，CIDECT（2001）的设计公式高估了最大SCF。对于混合重叠的管状K型接头的SHS弦和CHS牙套，当确定此类接头的最大SCF时，CIDECT（2001）设计公式并不保守。设计公式高估了大多数标本的最大SCF。此外，对于混合间隙管状K型接头的SHS弦和CHS支撑，CIDECT（2001）的设计公式高估了最大SCF。对于混合重叠的管状K型接头的SHS弦和CHS牙套，当确定此类接头的最大SCF时，CIDECT（2001）设计公式并不保守。设计公式高估了大多数标本的最大SCF。此外，对于混合间隙管状K型接头的SHS弦和CHS支撑，CIDECT（2001）的设计公式高估了最大SCF。对于混合重叠的管状K型接头的SHS弦和CHS牙套，当确定此类接头的最大SCF时，CIDECT（2001）设计公式并不保守。