Strength of Butt Welds and Transverse Fillet Welds in Very High Strength (VHS) Circular Steel Tubes

摘要

Axial tensile tests on butt welds and transverse fillet welds of very high strength (VHS) tubes were conducted. All failure happened in the heat-affected-zone. The section capacity of butt welds was almost the same as that of the fillet welds. The connection strength was about 49 percent of the base metal. The failure mode was compared with that of C350 and C450 square hollow sections (SHS). The linear increase trend, i.e. the higher the tube strength, the higher the welded connection strength, observed for C350 and C450 sections was not valid for VHS tubes. A linear reduction factor was proposed to take account of the effect of yield stress on welded connection strength. A design code based on the testing results was proposed. Possible strengthening methods are proposed in this paper, which include post-weld-heat-treatment, adhesive bonded joints and changing weld directions.