Searching for Bridge and Motorway graphics

In my scenario I want to replace rivers with water tiles and add bridges to cross them. I, of course, can use default piece of terrain, but I'd prefere to have appropriate graphics. Since my scenario is set in future, I'd like to have industrial-style bridge (though any modern will do).

I briefly searched through forums but couldn't find anything even close. So I'd be grateful if someone pointed me at a bridge graphics, that can be used for terrain or, at least graphics that can be converted.

Also I'd like to add modern-type motorways to replace road graphics. Not as important as bridge, but would be very nice.

Thank you in advance!