Experimental Study of Offset HSS Connections

The structural behavior of welded hollow structural sections (HSS) connections in which one member is laterally offset from the plane of a connection is investigated experimentally and compared with corresponding planar connections. Sixteen full-scale test connections, consisting of either T or N configurations fabricated from class C HSS, were tested at load levels comparable with those expected to occur in actual trusses. In all cases the mode of failure was by localized large deflections of the flange face and sidewalls of the compression chord. It was found that in the case of T connections, the reduction in capacity due to offsetting a member by as much as 17% of the width of the chord member from the central plane of the truss was marginal. N configurations, whose diagonal members were offset by 8% of the width of the chord member, showed a slight increase in ultimate strength. The design values obtained using both AISC LRFD and CIDECT specifications are compared with the test results where appropriate.