Evaluation of the new IIW CHS strength formulae for thick-walled joints

This paper presents the comparison between the new IIW strength equations (proposed by the Sub-commission XV-E) for circular hollow section X-, T- and K-joints and the finite element (FE) data for joints with very thick chord members. The chord diameter-to-wall thickness ratio 2 gamma in this investigation ranges from 7 to 40, which extends beyond the validity limit of most design equations. This study examines the applicability of the proposed IIW equations for thick-walled CHS joints under brace axial loads, under brace in-plane bending (IPB) and under brace out-of-plane bending (OPB). The comparison procedure filters out joints with member (brace or chord) failure and punching shear failure. The numerical data obtained from the extensive, calibrated nonlinear FE study demonstrate the applicability of the new IIW equations to thick-walled joints.