Investigations on the effect of weld penetration on fatigue strength of rib-to-deck welded joints in orthotropic steel decks

• Published in: International journal of steel structures Vol. 15; no. 2; pp. 299 - 310
• Main Authors: Dung, Cao Vu, Sasaki, Eiichi, Tajima, Keiji, Suzuki, Toshimitsu
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Steel Construction 01.06.2015; 한국강구조학회
• Subjects: Civil Engineering; Engineering; Materials Science; Solid Mechanics; 토목공학; steel bridges; fatigue; orthotropic deck; effective notch stress; weld penetration; rib-to-deck joints
• ISSN: 1598-2351; 2093-6311
• DOI: 10.1007/s13296-014-1103-4

A common practice for the manufacture of orthotropic steel decks in Japan is to use 75% partial joint penetration welds between closed ribs and deck plates. To evaluate the effectiveness of the proposed 100% penetration on improving the fatigue strength of rib-to-deck welded joints in orthotropic steel bridge decks, four full-scale orthotropic deck specimens were subjected to laboratory testing. Specimens, consisting of a 12-mm-thick deck plate and 6-mm-thick rib, with one closed rib, were fabricated with 75% and 100% penetration. Fatigue test results showed that fatigue cracks initiated from the weld toe inside the rib in the 100% penetration specimens, but from weld root inside the rib in the 75% penetration specimens. To investigate this fatigue behavior, strain measurements were taken at 5 mm from the rib-to-deck weld line. Results of finite element analysis using the effective notch stress method indicate that a deeper partial penetration results in a slightly higher effective notch stress at the weld root of the partial penetration weld. The effective notch stress at the crack initiation location with 100% penetration is lower than that obtained with partial penetration. The open angle appears to have a significant effect on the effective notch stress at the upper weld toe when using 100% penetration. Therefore, the proposed 100% penetration appeared to have a positive effect on enhancing the fatigue resistance of rib-to-deck welded joints.