In this study, an analytical investigation is conducted on stiffened connecting plates, which are a type of bridge unseating prevention device, by directly cutting steel plates to stiffen the openings of the connecting plates. The accuracy of the analysis is validated by tensile failure experiments. Moreover, analyses are performed using models with different thickness and width for the stiffened part, aiming to propose its effective thickness and width. The results indicated that controlling the cross-sectional area ratio and thickness-to-width ratio is effective for identifying an optimal model.
