Hello Rick,
I'm designing a simple span bridge using WF39DG with UHPC closure, currently working on the girder detail plan and have a question about the girder top flange thickness.
There is a table for Top Flange Thickness (Tf) on the WSDOT standard Girder Schedule plan, the flange thickness is 6" min. at mid span and increases toward each end. The thickness at centerline of bearing could be 11" for example, I'm wondering if 5" extra thickness somehow like the "A" dimension (although there's no "A" dimension in the standard Girder Schedule Plan)?
By the way, can I use consistent top flange thickness of 6" for the entire span and get the haunch/"A" dimension by applying concrete/HMA overlay (thicker at bearing and thinner at mid span)?
Thank you!
Yuan
The top flange thickening is sort of like the "A" dimension. If you want a perfectly flat roadway surface, but the girder cambers, thicken the top flange so that the top of girder is flat after camber.
You can also use the "Nonstructural Overlay" deck type and specify an "A" dimension.
The "nonstructural overlay" differs from the "wearing surface overlay" in that the former has variable depth as defined by the "A" dimension and the later is constant depth.
Neither overlay type contributes to the structural section. They are just dead load.
There is a trade off between using top flange thickening and a nonstructural overlay. Top flange thickening is performed by the fabricator and is part of the girder. Nonstructural overlay is cast on site and time must be built into the construction schedule for curing.
Rick,
Thank you so much for your reply for my question about the "A" dimension. Right now I have another question about WFDG design.
I'm designing WF39DG girder with nonstructural overlay on top with "A" dimension specified. In the "Girder Details" tab, I entered all the information for strands and mild reinforcement (both longitudinal and transverse), and it turns out the girder design works for my case.
The question I have is that I'm wondering if the girder top flange (working as bridge deck) is already designed/checked for traffic load by PGsuper program since the mild reinforcement was provided in the Girder Detail tab? Or I need to design it separately?
Thank you so much!
Yuan
PGSuper only performs the longitudinal design of the girder. Transverse design of the top flange acting as deck is outside the scope of the program.
Thank you so much Rick!