Structural characteristics of box girder bridge with strutted wing slabs

Concrete box girder bridges whose wing slabs are supported by struts have been constructed since early 2000’s in Japan. This girder type has been mainly applied to highway bridges for New Tomei Expressway. On the other hand, dozens of bridges with this girder type have been constructed since 1970’s in Europe. It is said that weight of superstructure can be reduced by applying this girder type when the bridge decks are wide. Although the advantages of this girder type are known as above, the structural characteristics of this girder are not thoroughly revealed yet since the past examples are still limited. The authors investigate the structural characteristics of the box girder with strutted wing slabs in terms of weight reduction through a comparison with other girder types, which have been applied to bridges constructed for New Tomei Expressway. The compared girder types include multi-cell box girder, single-cell box girder and box girder with ribbed slabs. The authors also investigate applicable width of the box girder with strutted wing slabs through a case study and quantitative comparison. It is concluded that box girder with strutted wing slabs is most effective for weight reduction of superstructure among the compared girder types. Even the superstructure weight of 2-lane highway bridges can be reduced by applying box girder with strutted wing slabs.