Influence of corrosion on seismic performance of steel beam-to-column connections

Steel structures are not only subjected to the threaten of single hazard (e.g., earthquake), but also suffers from the coupling environmental effect such as corrosion throughout the entire service life cycle. This study explores the seismic performance of steel beam-to-column connections after corrosion. Accelerated corrosion tests were conducted on a series of practical steel beam-to-column connections, and the seismic performances of the specimens before and after corrosion were compared. A modeling method of corroded steel members that considers distribution randomness of corrosion depth was proposed. Finally, the proposed method is applied to conduct time-dependent seismic performance prediction of corroded beam-to-column connections. The results show that corrosion mainly influences the buckling and post buckling behaviors of steel beam-to-column connections. Due to earlier appearance of local buckling, more evident stiffness degradation is observed for the corroded specimen. Corrosion also induces performance degradation of the panel zone. For the corroded specimen with cover plate, multiple small cracks initiate at the junction between the cover plate and beam flange, and fracture damage is more likely to happen for the beam-to-column connections after corrosion. Both yield and ultimate load-carrying capacities of the connections decrease linearly with the increase of accelerated corrosion time, and the load-carrying capacity deterioration rate of the cover plate strengthened connection is quicker than that of the un-strengthened connection. The initial stiffness approximately degrades linearly with the increase of corrosion time. Corrosion degree also influences the energy dissipation capability of the beam-to-column connections, especially after the occurrence of local buckling.