I have some in the far side of the family who was overseeing bridge builds.
He told a story about how he had a vacation in the middle of a build, and when he was away somebody else miscalculated ever so slightly in a corner at the base of the bridge.
Center part missed out by over a metre of difference. So when he got back, they had to redo both sides for a big part to make it hit perfect again. 6 months of extra work xD