Triangular Truss Joints Using Rectangular Tubes

This paper deals with the behavior and design of welded joints to the tension chord of triangular trusses, with two Warren‐type web planes and a single tension chord, made of rectangular tubes (hollow structural sections or HSS). Experimental programs are outlined in which simplified double‐T joints and triangular truss segments with double‐K gap joints were tested. Parameters investigated include the gap size, the web‐member‐width‐to‐chord‐width ratio, the chordwall‐width‐to‐thickness ratio, and the angle between web planes. The mechanics of deformations of the double‐T and double‐K joints are discussed in relation to yield line theory, and this theory is shown to give a good prediction of the experimental joint stiffnesses and strengths. Strength equations are proposed to cover tension chord gap joint behavior with respect to chord wall bending and a design example is outlined.