In the current Japanese Specifications for Highway Bridges (JSHB), the design methods for bridge members made of high strength steel are not specified. The design of such members is, therefore, carried out by using the ultimate strength curve similar to that of mild steel members, and the ultimate strength curve is not verified for the members made of high strength steel. In this study, the ultimate strength of beam-columns made of high strength steel designed by the ultimate interaction curve of JSHB is investigated through a parametric study based on elasto-plastic and finite displacement analyses considering the inherent characteristics of residual stress distribution and stress-strain relationship of high strength steel. It is concluded that the ultimate interaction curve of JSHB can be used for the design of beam-columns made of high strength steel but it is a little bit conservative.
