Experimental Study on the Flexural Behavior of a Novel Nonprismatic Prestressed UHPC Composite Box Girder with Corrugated Steel Webs

Owing to the remarkable advantages, such as the appealing appearance, light self-weight, efficient application of prestressing, and the optimal shear force and bending moment distributions in the webs, prestressed concrete composite box girders with corrugated steel webs (CBGCSWs) are widely utilized in highway bridges nowadays. To further improve the cracking resistance of traditional prestressed concrete CBGCSWs in the tensile zone and negative bending region and to promote the application of ultrahigh-performance concrete (UHPC) in long-span highway bridges, this paper proposed and designed a novel nonprismatic prestressed UHPC composite box girder with corrugated steel webs (CSWs) (i.e., CSW-UHPC composite box girder). A large-scale (5.55 m long) nonprismatic prestressed CSW-UHPC composite box girder was experimentally and numerically studied to investigate its cracking behavior and flexural performance through the bending test and finite-element analyses. Experimental results of the deflections, strains, cracks development and crack patterns, cracking moments, and ultimate flexural capacity of the girder were acquired. In addition, the calculation methods of the first cracking moment, nominal cracking moment, and the ultimate flexural capacity of the girder were comprehensively investigated, and the analytical results agreed relatively well with the experimental ones. The proposed novel nonprismatic prestressed CSW-UHPC composite box girder exhibited excellent cracking performance and flexural capacity. Results obtained from the present study could serve as a good reference for the flexural design of the prestressed CSW-UHPC composite box girders.