I'm encasing the abutment ends of prestressed concrete bridge girders in concrete before the deck pour. (For lateral stability and to prevent the soil from spilling through.)
Discussion of intermediate diaphragms for prestressed girders abounds, but I haven't found information on structural behavior of end diaphragms.
For purposes of a consulting engineer
My gut / engineering judgment is telling me the effect is negligible, but I prefer to understand what's actually going on before making simplifying assumptions.
Conceptually (versus a girder without the diaphragms):
- Does this change deflections during the deck pour? What about long-term deflections?
- Does this change the live load moments &/or shears?
- Is there any logic by which the encased length should be a function of girder depth or span length?
I've put a sketch below since terminology and typical bridge configurations vary around the world.