Design of Highway Bridges by Barker and Puckett is easy to understand and has some nice example problems. The edition I have from 1997 though. I'm sure there must be AASHTO LRFD books that are more recent that Barker and Puckett.
If you are looking for example designs, take a look at the AASHTO Subcommittee on Bridges and Structures website. They have two complete design examples, one for a steel girder superstructure and one for a prestressed concrete girder superstructure that were developed for the Federal Highway Admin. They both include substructure design as well (abutments & piers). Somewhat dated but still thorough.
If you are looking to save some $$$ the AASHTO LRFD examples mdbridge provided are the way to go. They are very through and free to download! Of course you won’t get the kind of in depth coverage you’d get in a text book, but you will save a couple hundred bucks.