Structural behaviour and design of high strength steel CHS T-joints

This paper investigates the structural behaviour of high strength steel (HSS) circular hollow section (CHS) T-joints under brace axial compression. Finite element analysis on CHS using S460, S700, S900 and S1100 was conducted, chord plastification failure examined. The effect heat affected zones (HAZ) joint influences grade, to diameter ratio (β) wall thickness (2γ) suitability CIDECT mean equations for HSS were evaluated. HAZ initial stiffness is found be insignificant. material softening in can lower strength; however, reduction less pronounced. In general, influence β minor. prediction relatively accurate S460 becomes increasingly unconservative higher grade larger 2γ ratio. because improved yield stresses generally could not fully utilised due adopted indentation limit 3% diameter. It suggested tighten range ≤ 40 grades ranging from S700 30 greater than up allow more effective use HSS. validity 0.2 1.0 also recommended S1100. Mean design modified proposed with ratios which are within ranges.