Fatigue cracking of shoulder beams and I-shaped corbels within four-limb CFST columns

• Published in: Journal of constructional steel research Vol. 220; p. 108812
• Main Authors: Liao, Xu, Zhao, Xuan, Li, Xian, Hu, Zhao-Hui, Liu, Jun, Nie, Ying, Chen, Si-Yu, Liu, Xi-Guang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2024
• Subjects: Dynamic stress responses; Fatigue cracking; Four-limb CFST columns; Heavy industrial plants; I-shaped corbel; Shoulder beam; I-shaped corbel; Shoulder beam; Four-limb CFST columns; Dynamic stress responses; Heavy industrial plants; Fatigue cracking
• ISSN: 0143-974X; 1873-5983
• DOI: 10.1016/j.jcsr.2024.108812

The cracking of shoulder beams and corbels in heavy industrial plants under cyclic crane loads is a significant and concerning issue in China, posing a threat to production safety. To address this problem, a field investigation was conducted to examine the cracking situation of shoulder beams and corbels within four-limb concrete filled steel tube (CFST) columns in a heavy industrial plant with 11 years of service. On-site testing was performed to analyze the strain responses and investigate the cracking mechanism in the ortho-welded zones under crane operating loads. Additionally, finite element methods were utilized to assess the impact of factors such as the number of cranes, longitudinal eccentricity of crane beams, and local suspension of supports on the stress distribution of shoulder beams and corbels. The investigation revealed that operating two cranes led to different levels of fatigue life reduction in the welds of the shoulder-beam and corbel compared to using just one crane. The horizontal welds on the upper flange of shoulder beams or corbels, originally expected to be subjected to compression under design loads, experienced local tension due to eccentric loading and support suspension caused by long-term dynamic crane operations. Moreover, eccentric loading and support suspension increased the shear stress on vertical welds found on webs and stiffeners. The tensile stress and increased shear stress led to fatigue cracking in both the horizontal and vertical welds under cyclic crane loads. Therefore, future design and construction of heavy industrial plants should meticulously consider the adverse effects induced by both longitudinal eccentricity of crane beams and support suspension. Fig. 1 The main content of this study. [Display omitted] •The cracking of shoulder beams and I-shaped corbels were investigated on site.•Cracking mechanism of shoulder beams and I-shaped corbels was studied.•Load eccentricity resulted in local tension of horizontal welds on the upper flange.•The eccentric crane load reduced the service life of the shoulder beams and corbels by 40%–80%.