Experimental Study on the Welding Residual Stresses of Integral Joint Using Full-Scale Joint Model of a Steel Truss Bridge

Abstract

In order to study the residual stress distribution of the welded integral joint of steel truss bridge, a full-scale model was fabricated with the same welding process, same material as the real bridge in the bridge workshop. The residual stress state and distributions of residual stresses in the full-scale model were measured using blind-hole strain-gage method. The tested results show that high residual stress is caused during the welding process and the maximum tensile residual stress may reach the yield strength of the steel. Longitudinal tensile residual stress appears in the regions near the welding bead and changes to compressive stress at a certain distance from the welding bead, with the maximum tensile residual stress being in the centre of the welding bead. In butt-welding between two plates with different thicknesses, the value of welding residual stress in the thinner plate is lower than that of the thicker one. The results presented in this paper would be useful as references for developing measures of reducing the residual stress of integral joint in the fabrication of a real bridge.