Abstract
Change in fatigue strength of unpainted welded joints of weathering steel and structural steel due to long term atmospheric exposure is one of the essential factor in using the weathering steel for bridges. Fatigue tests of 10-year weathered 19 stiffener specimens and 9 gusset specimens were carried out. Additional 11 non-weathered gusset specimens were tested for comparison. The fatigue test results were compared with previous fatigue test data. It was found that no reduction in fatigue life was observed even after 10-year of weathering, comparing with the non-weathered, 2-year and 4-year weathered specimen. The runout levels of fatigue strength were also increased, because more data became runout even at higher stress range levels. Measurement of weld toe profiles indicated that the gain in fatigue strength is due to the increase in weld toe radius.
