Ultimate Load Capacity Analysis of Q690 High-Strength Steel KK-Type Tube–Gusset Plate Connections

Abstract

A KK-type tube–gusset plate joint is a typical joint configuration used widely in the tubular structures of transmission towers. The mechanical characteristics of KK-joints, compared with K-joints, are more complex owing to the multiplanar effects in the actual structure. Based on material experiments and tubular K-joint ultimate load capacity experiments of Q690 high-strength steel, a parameter analysis is conducted on KK-type tube–gusset plate connections. Additionally, geometric parameters, axial load of the chord, and other factors that influence the ultimate bearing capacity of multiplanar KK-joints are studied in detail. The analysis indicates that the axial compression load of the chord, chord wall thickness, chord diameter, and loading ratio of the bracing members significantly affect the ultimate load capacity of KK-joints. According to the experimental and finite-element (FE) analysis results, a formula is developed to predict the ultimate load capacity of KK-joints using the virtual work principle.