Static analysis on fatigue crack retrofitting using steel-rod reinforcement method: Fid-Bau Portal

Static analysis on fatigue crack retrofitting using steel-rod reinforcement method

Meng, Cheng / Yuanzhou, Zhiyuan / Ji, Bohai / Chen, Zhuangzhuang / He, Bang

Highlights • A new approach called steel-rod reinforcement (SRR) method with less structural damage was proposed to repair fatigue cracks in steel box girder. • The simplified mechanism model of SRR method was established and verified by FE modeling and validation, and experimental study. • Reasonable parameters of SRR method were evaluated.

Abstract Restricted by the closure property of U-rib, the current methods for repairing U-rib fatigue cracks tend to carry the risk of structural damage and new fatigue sources. To mitigate these issues, a new approach, called steel-rod reinforcement (SRR) method, was proposed herein. Theoretical analysis was carried out to investigate the reinforcement mechanism, as well as the numerical simulations. The performance after SRR method was evaluated using static tensile tests, then the parameters were discussed by comparing the effect on reducing stress concentration. The results show that SRR method has good effect on stress concentration reduction at the crack tip. The effective crack length will be reduced, lowering the stress intensity factor, according to the equation presented in this work, after the steel-rods are installed. The maintenance effect improves with an increase in the number of the steel-rods. Reasonable pretightening torque on bolts and recommended distance between steel-rods are suggested as 35 N m and 40 mm, respectively. The addition of optional round shims with varying thicknesses enhances the applicability of this method.