Abstract The experimental investigation presented in this study focused on the static strengths and load-deformation behaviour of cold-formed high strength steel tubular X-joints made up of S900 and S960 steel grades. The X-joints include brace members made up of square, rectangular and circular hollow sections, while chord members were made up of square and rectangular hollow sections. The nominal yield strengths of square and rectangular tubular members were 900 and 960 MPa, while the nominal yield strength of circular tubular members was 900 MPa. Two configurations of tubular X-joints were fabricated, first, where both brace and chord members were made up of square and rectangular hollow sections, and second, where circular hollow section braces were welded to square and rectangular hollow section chord members. The welds were laid using semi-automatic gas metal arc welding process. A total of 34 tests was conducted where an axial compression was applied through the brace members without any chord preload. The ratio of brace-to-chord width (β) ranged from 0.34 to 1, brace-to-chord thickness (τ) from 0.53 to 1.28, chord width-to-thickness (2γ) from 20.2 to 38.9, and chord side wall slenderness (h0/t0) from 12.7 to 39.0. In order to assess the applicability of the existing design provisions, test strengths were compared with the nominal strengths obtained from the Eurocode 3 (EC3) and CIDECT. It is shown that the existing design provisions are not capable of providing accurate and reliable predictions for cold-formed high strength steel tubular X-joints made up of S900 and S960 steel grades.

中文翻译：

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冷弯高强钢管X型接头在支撑轴压下的结构性能

摘要 本研究中提出的试验研究侧重于由 S900 和 S960 钢种组成的冷弯高强度钢管 X 型接头的静强度和载荷变形行为。X 型接头包括由方形、矩形和圆形空心截面组成的支撑构件，而弦杆由方形和矩形空心截面组成。方形和矩形管状构件的公称屈服强度为 900 和 960 MPa，而圆形管状构件的公称屈服强度为 900 MPa。制造了两种管状 X 形接头，首先，支撑和弦杆构件均由方形和矩形空心截面组成，其次，圆形空心截面支撑焊接到方形和矩形空心截面弦杆构件。焊缝采用半自动气体保护金属电弧焊工艺铺设。总共进行了 34 次测试，其中在没有任何弦预紧力的情况下通过支撑构件施加轴向压缩。支撑弦宽比(β)为0.34-1，支撑弦厚(τ)为0.53-1.28，弦宽-厚比(2γ)为20.2-38.9，弦侧壁细长 (h0/t0) 从 12.7 到 39.0。为了评估现有设计规定的适用性，将测试强度与从欧洲规范 3 (EC3) 和 CIDECT 获得的标称强度进行了比较。结果表明，现有的设计规定不能为由 S900 和 S960 钢种组成的冷弯高强度钢管 X 型接头提供准确可靠的预测。总共进行了 34 次测试，其中在没有任何弦预紧力的情况下通过支撑构件施加轴向压缩。支撑弦宽比(β)为0.34-1，支撑弦厚(τ)为0.53-1.28，弦宽-厚比(2γ)为20.2-38.9，弦侧壁细长 (h0/t0) 从 12.7 到 39.0。为了评估现有设计规定的适用性，将测试强度与从欧洲规范 3 (EC3) 和 CIDECT 获得的标称强度进行了比较。结果表明，现有的设计规定不能为由 S900 和 S960 钢种组成的冷弯高强度钢管 X 型接头提供准确可靠的预测。总共进行了 34 次测试，其中在没有任何弦预紧力的情况下通过支撑构件施加轴向压缩。支撑弦宽比 (β) 为 0.34 至 1，支撑弦厚比 (τ) 为 0.53 至 1.28，弦宽比 (2γ) 为 20.2 至 38.9，弦杆侧壁细长 (h0/t0) 从 12.7 到 39.0。为了评估现有设计规定的适用性，将测试强度与从欧洲规范 3 (EC3) 和 CIDECT 获得的标称强度进行了比较。结果表明，现有的设计规定不能为由 S900 和 S960 钢种组成的冷弯高强度钢管 X 型接头提供准确可靠的预测。支撑弦宽比(β)为0.34-1，支撑弦厚(τ)为0.53-1.28，弦宽-厚比(2γ)为20.2-38.9，弦侧壁细长 (h0/t0) 从 12.7 到 39.0。为了评估现有设计规定的适用性，将测试强度与从欧洲规范 3 (EC3) 和 CIDECT 获得的标称强度进行了比较。结果表明，现有的设计规定不能为由 S900 和 S960 钢种组成的冷弯高强度钢管 X 型接头提供准确可靠的预测。支撑弦宽比(β)为0.34-1，支撑弦厚(τ)为0.53-1.28，弦宽-厚比(2γ)为20.2-38.9，弦侧壁细长 (h0/t0) 从 12.7 到 39.0。为了评估现有设计规定的适用性，将测试强度与从欧洲规范 3 (EC3) 和 CIDECT 获得的标称强度进行了比较。结果表明，现有的设计规定不能为由 S900 和 S960 钢种组成的冷弯高强度钢管 X 型接头提供准确可靠的预测。测试强度与从欧洲规范 3 (EC3) 和 CIDECT 获得的标称强度进行了比较。结果表明，现有的设计规定不能为由 S900 和 S960 钢种组成的冷弯高强度钢管 X 型接头提供准确可靠的预测。测试强度与从欧洲规范 3 (EC3) 和 CIDECT 获得的标称强度进行了比较。结果表明，现有的设计规定不能为由 S900 和 S960 钢种组成的冷弯高强度钢管 X 型接头提供准确可靠的预测。