How did bridge builders of old ensure both ends of the bridge would perfect meet in the middle before laser measuring was around?
In: Engineering
They did pretty much what I did when I built a fence around my house:
* Put a stick at either end.
* Have someone at one of the sticks, looking so that both sticks line up.
* Have someone else put remaining sticks in a line between them, lining up the top of the sticks with that sight line.
Accurate to within a millimeter or so, if done carefully.
Sure, they probably didn’t line up sticks, but the principle remains. With two set points, one at each end, it’s very easy to accurately put stuff on a straight line between them.
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