Here's a little set of non functional bridges ive been working on, the following are:
An old metal suspension bridge
An ancient stone bridge
An old arched stonebridge
and a North American type covered bridge in wood.

And that's not all, i also included some diagonal oriented ones of 4 of the models.

There are some visual glitches due to the LODs  ( i tried as best as i could...) , but as long as you cover them up cleverly with either flora, or other items they should look fine, this mostly applies to the approaches.
Either way i hope you can find some usage for these.

Dependencies:
Meandering Bike Paths

PEG SUPER MTP PACK
  Mod Edit: Fixed dependency links (from old URL format).