Resistance of gusset-tube DK-joints stiffened by 1/2 annular plates in transmission towers. (August 2019) - Li, Fang
Abstract: Gusset-tube double K-type joints (DK-joints) stiffened by annular plates are widely applied in transmission towers. However, the literature concerning these joints is scant, as DK-joints are spatial joints, so it is difficult to achieve three-dimensional (3D) loading in experiments. In this paper, full-scale tests of DK-joints were accomplished. An equivalent model in which the brace forces were substituted by a shear force ( P v ) and a bending moment ( M w ) was adopted. Then, the parametric analysis was carried out to derive empirical formulas of the design resistances for DK-joints. Furthermore, the failure patterns and capacities of DK-joints with and without annular plates were compared with those of uniplanar K-joints. The present study obtains that, concerning one gusset plate, the ultimate shear capacity ( P v, u ) of DK-joints is about 0.6 times that of K-joints and that DK-joints stiffened by annular plates have larger ultimate moment capacities ( M w, u ) than those without annular plates. Moreover, annular plates do not affect P v, u but can affect M w, u significantly. Annular plates have a 'hoop effect' on K- and DK-joints. Highlights: Design resistance and failure modes of DK-joints with annular plates were investigated. Full-scale three-dimensional experiments of DK-joints were achieved. Ultimate strength equations for DK-joints with annular plates were proposed. DK-joints with annular plates were compared with that without annular plates and uniplanar K-joints.