Can anybody recommend a good reference book about the analysis and design of minor elements of a steel bridge, e.g. diaphragm over bearing, stifferners........
Stiffeners have to be designed in accordance with AASHTO, as columns.
I've never come across anything for end diaphragms (unless you're assuming it's a primary member as in a curved structure). I just place one or two wheel loads (depending on the stringer spacing), apply 30% impact, and design it as a simple span beam