Effects of galvanizing on residual stresses and stress concentrations in RHS X- and T-Connections

Abstract

Complementary studies showed that post-production hot-dip galvanizing changes residual stress magnitudes and distributions in cold-formed hollow structural section (HSS) members and can affect their behaviours under axial compressive and flexural loads. However, research on the effects of galvanizing on HSS connections is insufficient. Similar to previous research, in this research a comprehensive measurement of residual stresses was performed, using the hole-drilling approach and a total of 144 strain gauge elements at 48 locations of interest on the connection specimens. The experimental program includes two galvanized and two ungalvanized rectangular hollow section (RHS) connection specimens with different branch-to-chord width ratios (β). The effects of fabrication (cold forming and welding) and post-fabrication (galvanizing) processes on residual stresses at various locations of the specimens are investigated and compared. The effects of galvanizing-induced residual stress changes on stress concentrations at the critical locations at different fatigue load levels are studied. The connection specimens were subsequently tested under branch axial compressive forces to failure to compare their performances under static loading.