Experimental study on fatigue damage mitigation in welded beam-to-column connections with passive vibration control

To investigate the effectiveness of a viscous fluid damper (VFD) in mitigating fatigue damage in welded beam-to-column connections, six specimens were manufactured with the full penetration groove weld process. These specimens were divided into three groups: S1, S2, and S3, each containing two specimens. One specimen in each group was equipped with VFD, while the other was not. All specimens underwent the same elastic cyclic loading stage, but a different plastic cyclic loading stage for each group. The study results indicate that the presence of VFD can significantly enhance the load-bearing capacity of the welded beam-to-column connection by 10%–15% when subjected to the same displacement amplitude at the beam end. The primary cause of failure in the welded beam-to-column connection is the fatigue damage of the weld toe on the beam flange, which requires more attention during the welding process. Additionally, the VFD can effectively reduce stress concentration at the weld seam area, leading to a maximum of 50% decrease in the maximum stress near the weld toe of the beam flange center, as observed in our study.