Residual shearing strength of fillet weld connections after exposure to elevated temperature

Abstract

Experimental and analytical studies are carried out to investigate the residual shearing strength of fillet welded connections after exposure to elevated temperatures. Transverse fillet welds and longitudinal fillet welds were designed in the test, and four weld leg heights were considered. Fourteen specimens were manufactured for each weld leg height, including seven heating temperatures and two cooling methods, obtaining a total of 112 specimens, along with 8 unheated specimens for comparison. The load-displacement curves and stress-load ratio curves were obtained to evaluate the shearing strength, residual deformation, stress development, stiffness and ductility of the fillet welds. Test results exhibit the transverse fillet welds are mainly integral fracture, while longitudinal fillet welds occur obvious local and global cracks. The weld leg height has the greatest influence on the shearing resistance of fillet welds, followed by the elevated temperature and cooling method. When the heating temperature is between 400 °C-600 °C, an increasement in residual shearing strength can be noticed. Meanwhile, the residual deformation is positively correlated with the weld leg height. Additionally, water-cooling fillet welds are superior to room-temperature-cooled fillet welds in terms of stiffness and ductility. Moreover, the formulae for predicting the residual shearing strength of the fillet welds after exposure to elevated temperatures are proposed.