Unified Approach for Liveload Moments and Deflections in Orthotropic Bridge Deck Due to CHBDC Truckloading

The current Canadian Highway Bridge Design Code includes design provisions to establish live load moment demands for reinforced concrete decks over longitudinal girders, orthotropic deck over longitudinal girders, and orthotropic deck over transverse beams. However, it only provides an equation for the factored applied moment on the deck as a function of the girder spacing, neglecting the effect of flexural and torsional rigidities of the deck. As a result, a parametric study was carried out in order to produce new empirical expressions for moment in bridge decks subjectedto truck wheel loading, takinginto account each of the three cases oforthotropy, namely: relatively torsionally stiff, flexurally soft decks, relatively uniformly thickness decks, and relatively torsionally soft, flexurally stiff decks. Bridge deck design can be treated in a unified manner across different deck types using the proposed formulations, accounting for longitudinal and transverse flexural rigidity of decks. The use of these methods can significantly simplify deck analysis and allow bridge engineers to compare different deck design alternatives.