Study on the mechanical properties of novel wide box girders stiffened by transverse ribs under a temperature effect

Abstract

Bridge structures are developed to be wider and lighter with increasing traffic flow, thus traditional box shape sections may no longer be optimal in the structural design of a wide flanged girder. Accordingly, box girders stiffened by transverse ribs are gaining favour from designers because they can -not only- to significantly lighten the dead load of the superstructure, but also effectively widen the bridge deck. Due to the influence of stiffening ribs, the mechanical properties of box girders with solid slabs are quite different from those with ribbed slabs. However, the existing literature merely reports the geometrical characteristics and dimensions of the ribbed box girder, while there are few reports on its mechanical properties under temperature action. In this study, the differences in transverse mechanical properties between box girders with solid slabs and ribbed slabs subjected to temperature action are investigated. The study showed that the arrangement of transverse ribs underneath the top slab results in additional thermal stresses in the ribbed slab under temperature loading. Because the transverse ribs changed the distributions of thermal stresses in the top slab of the transversely ribbed box girder, the temperature field and thermal stress state of the ribbed slab were significantly different from those in the solid slabs. Furthermore, a significant stress concentration appeared in the internal ribs inside the ribbed box girder, which should be considered in structural design.