Resistance of gusset-tube DK-joints stiffened by 1/2 annular plates in transmission towers

摘要

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,P- (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,M- u) than those without annular plates. Moreover, annular plates do not affect P-v,P- (u) but can affect M-w,M- (u) significantly. Annular plates have a 'hoop effect' on K- and DK-joints. (C) 2019 Elsevier Ltd. All rights reserved.