Transverse Analysis of a Prestressed Concrete Wide Box Girder with Stiffened Ribs

Abstract

For concrete box girders with wide flanges, a ribbed slab can increase the cantilever length and transverse stiffness while reducing the dead weight of the deck. For single box girder bridges with a large width-to-span ratio, the traditional cross section of a single-cell box girder (the two-web box section) can lose efficiency because of the effect of shear lag, cross-section distortion, and transverse bending moments. A literature search revealed that the prestressed concrete box girder with transverse ribs is already used in certain countries to meet the requirements of wide bridge decks of single-cell concrete box girders. However, little research has been conducted on the mechanical properties of this spine-like box girder, although it has been used in many applications. In this paper, the structural forms and dimensions of a concrete box girder with wide flanges and a ribbed slab are introduced on the basis of design experience. A significant difference in the mechanical performance of ribbed box girders and conventional box girders was observed in the influence of the stiffened ribs. Therefore, on the basis of engineering practices, three representative three-dimensional (3D) finite-element models (i.e., ribbed box girder, equivalent box girder, and ordinary box girder) were established to quantitatively investigate the influence of stiffened ribs on transverse stress under the action of gravity and vehicle loads. The results of this investigation can be used as a reference for designing and constructing similar projects.