Numerical Study on the Mechanical Properties of the Novel Wide Box Girders Stiffened by Transverse Ribs

The dimensioning of the cross section is a critical step in designing wide box girder bridges with long cantilevers. The typical box girder cross section may not be the most economical and reasonable choice for wide box girder bridges considering the stress conditions and construction costs. Arranging transverse stiffened ribs underneath the top slab is an effective way to widen the bridge deck. In this study, the influence of the transverse stiffened ribs on the mechanical performance of the ribbed top slab is investigated by finite element (FE) modelling. The results show that the transverse mechanical properties of the box girders with ribbed slabs are significantly different from those of the traditional box girders with solid slabs. The ribbed slabs can provide additional transverse capacities over those of the traditional solid slabs. Furthermore, the transverse tensile stress in the root section of the ribbed cantilever slab is found to fluctuate periodically along its length, and a considerable stress concentration is observed in the transverse ribs. The key design parameters of the transverse ribs (depth, width and spacing) influencing the tensile stress amplitude at the cantilever root section are determined through FE parametric analysis.