Here is the full list of all 13 Bridge Project achievements.
Create and share a custom map to the Steam Workshop
Solved all Cities' Bridges
Solved all Briges Group #4
Solved all suspension bridges
Solved all game maps
Solved all Canyon's Bridges
Solved 24 bridges
Solved 32 bridges
Solved 16 bridges
Solved all draw bridges
Solved all Farm's maps
Solved 8 different bridges
Solved Bridge Farm # 8 using wood only