An Investigation on Combined Section by Steels with Different Strengths for Bridge Girder

A basic investigation was carried out in this study to propose a new structure for steel bridge girders by using a combined section composed of steels with different strengths. SM400 as an ordinal strength level steel was selected as the base material for the I-section girder model. It was assumed that the lower flange of the I-section was replaced with an inverted T-shaped member by welding. This member was provided by the different steel with SM400A. The dimension of the inverted T-shaped member was selected to decrease the cross-sectional area to the original section. Furthermore, the moment of inertia and the yielding moment were aimed to increase from those of the original section. With satisfying these conditions, the possibility of cost-saving by using high-strength steel such as SBHS500 was examined. A series of investigations showed the optimum dimensions simultaneously satisfying these mechanical and economic conditions despite being limited.