Fatigue life prediction of concentrically braced frames with H-section steel

Fatigue life prediction is valuable for structural analysis and safety evaluation. The low -cycle fatigue life of a concentrically braced steel frame is determined by identifying the lower value obtained from comparing the bracing member's and the gusset plate's fatigue life. The present study performs simulations on 192 single diagonal concentrically braced frames with H -section steel (Q355B) to investigate their low -cycle fatigue behavior. The influential factors that significantly impact both the bracing member's fatigue life ( N B ) and gusset plate's fatigue life ( N C ) are discerned through the analysis of simulation results. Probabilistic prediction models for both N B and N C within the braced steel frame are formulated. Bayesian updating method is used to estimate model parameters. The results show that the selected important influence factors for N B are the bracing member's slenderness ratio ( lambda B ), the ratio of column length to beam length ( xi ), the width -to -thickness ratio of the bracing member's flange ( b / t f ), the connection efficiency ( eta ), and the inter -story drift ( delta ). Similarly, the selected important influence factors for N C consist of lambda B , eta , xi , delta , and the gusset plate's slenderness ratio ( lambda p ). The obtained results and proposed models can be as a supplement to existing specifications, which is helpful to predict the fatigue life for braced frames during the structural design process.