Recent Research Advances and Development of ISO 14346 Design Standard for Failure Modes of RHS Joints

Abstract

In recent years, considerable research efforts have been devoted to rectangular hollow section (RHS) joints, aiming to re-examine suitability of codified design provisions for steel grades up to S460 and to extend the validity range beyond S460. Within the research framework of drafting the next-generation international design standard ISO 14346 for hollow section joints, this paper presents recent research advances and improved design methods for RHS joints under brace axial compression or tension, failing by essential failure modes. For chord sidewall failure, the representative modified IIW method and an alternate Lan-Kuhn method together with the subsequently proposed Kim-Lee method are compared and evaluated against existing test and numerical evidence. Further, an upper limit of the codified chord sidewall bearing length is proposed to avoid overestimations for thick-walled RHS joints. For interactive chord sidewall and chord face failure, more-suitable limiting beta ranges for the occurrence of this failure mode and a linear interpolation design method are suggested. Design rules and recommendations are then proposed for chord sidewall failure and interactive failure, which have been approved to be included in the next draft of ISO 14346.