Static strength of thick-walled CHS X-joints—Part I. New approach in strength definition

This paper presents a new approach in the definition of joint strength for thick-walled circular hollow section (CHS) X-joint subjected to brace axial loading. This is based on the plastic load approach for limit analysis of pressure vessel components proposed by Gerdeen. A consistent coefficient λ associated with the plastic load approach has been determined, and the corresponding joint strength for X-joint under brace axial loads is found to correlate closely with the results obtained using Lu’s deformation limit. The strength prediction for thick-walled CHS X-joint using the present approach is found to be in good agreement with design recommendations by ISO and CIDECT for joints with chord radius-to-thickness ratio γ>7. For X-joints with γ<7, significant difference in results is observed especially with the ISO recommendation for joints with brace–chord diameter ratio β≥0.7.