Vol. 22, No. 4, pp. 471-482 (2026)
EFFECT OF POROSITY DEFECTS ON THE FATIGUE BEHAVIOR OF
WELDED JOINTS IN STEEL BRIDGE
Ying-Fang Yang 1, Zhen-Nan Peng 2, Ling-Zheng Wu 3, Yi-Qian Zhang 4, Qing-Hua Zhang 4 and Chuang Cui 4, *
1 Central Research Institute of Building & Construction Co., Ltd., MCC Group, Beijing 100088, China
2 Shenzhen-Zhongshan Link Administration Center, Zhongshan 511462, China
3 Guangshen Expressway Expansion Project Office, Dongguan 523141, China
4 State Key Laboratory of Bridge Intelligent and Green Construction, Southwest Jiaotong University,
Section 111 of Northbound 1, Second Ring Road, Chengdu, 610031, Sichuan, China
*(Corresponding author: E-mail:This email address is being protected from spambots. You need JavaScript enabled to view it.)
Received: 30 September 2025; Revised: 20 January 2026; Accepted: 22 January 2026
DOI:10.18057/IJASC.2026.22.4.10
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ABSTRACT
Welding technology offers high efficiency and flexibility in the bridge construction. However, weld-included defects are inevitable and significantly reduce the fatigue performance of welded joints. Porosity is one of the most common welding defects and has a considerable influence on fatigue performance. In this study, both fatigue tests and numerical simulation are used to investigate the effect of porosity defects. Test specimens of butt-welded and cruciform-welded joints were designed, with 48 specimens divided into two groups, including 24 specimens with porosity defects and 24 control specimens without pores. The results indicate that the fatigue strength of butt-welded joints and cruciform-welded joints without porosity defects with 2 million cycles was 142.0 MPa and 92.3 MPa, respectively. When the pore depth and diameter were both 2.0 mm, the fatigue strengths of butt-welded joints and cruciform-welded joints with porosity defects decreased by 27.4% and 7.3%, respectively. Numerical simulation results showed that porosity significantly increased the stress concentration factor (SCF) of the welded joints. The diameter, position, and depth of porosity had clear effects on SCF. An increase in the pore diameter significantly elevated SCF, although the rate of increase diminished when the diameter exceeded 1.6 mm; the SCF decreased when the pore was located farther from the weld toe, with cruciform joints being more sensitive to pore position; surface pores caused significantly higher SCF than internal pores, and the SCF was higher when pore depth was closer to the weld surface.
KEYWORDS
Welded joints, Porosity defects, Fatigue performance, Stress concentration factor, Numerical simulation
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