Review of fatigue assessment approaches for tubular joints in CFST trusses

Specimen testing of concrete-filled steel-tube (CFST) joints and the fatigue assessment approaches for such joints were investigated and summarized to understand comprehensively the fatigue behavior of CFST trusses. The main factors that influence the fatigue resistance of CFST joints were discussed. Nominal stress- and hot-spot stress (HSS)-based methods were compared based on available experimental results, and the current state and development direction of fatigue assessment of CFST joints were explored. Results showed that the fatigue failure mode, fatigue damage mechanism, anti-fatigue optimization design, and fatigue strengthening technology of CFST joints are more complex than those listed in fatigue design guidelines or specifications. Sufficient fatigue specimen testing and finite element analyses are necessary to predict the fatigue behavior of CFST joints via the HSS approach. Fracture mechanics approaches for the fatigue damage mechanism of welded tubular joints is a future research direction.