Fracture Mechanism and Performance Analysis of CHS Welded Connections with through Plates

In mid-high-rise steel structures, Circular or Rectangular Hollow Sections (CHS/RHS) have emerged as recommended structural members. Nonetheless, the complexity of beam-to-column joints of these members often necessitates extensive use of materials and labour force. Using Laser Cutting Technology (LCT) to fabricate CHS/RHS joints can offer highly precise, simplified, yet robust beam-to-column joint solutions. To estimate the joint capacity and failure mechanisms of of LCT joints, this study introduces detailed material and tensile test results on various CHS LCT welded joints (CHS-LCT-W), including full penetration groove weld (CJP) and full/partial strength fillet weld (FSFW/PSFW) specimens. Subsequently, finite element (FE) models validated by experimental results, are used to conduct parametric studies, and then, design recommendations are proposed for CHS-LCT-W joints based on their performance. Relevant findings highlight that whilst both the CJP and FSFW techniques can provide adequate capacity for the joints, full strength fillet weld joints (CHS-LCT-FSFW) represent the most efficient solution compared to complete joint penetration groove weld joints (CHS-LCT-CJP), particularly for CHS columns with thick walls. Finally, to derive design capacity equations for CHS-LCT-FSFW joints, that incorporate effective length, primary failure, and relevant equations according to European and American standards, a linear regression analysis has been applied to 33 experimental/numerical joints data.