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
To blow your mind, the middle of this bridge washed out and they rebuilt it. It has a bit of a kink now. Steel beam suspension bridge. https://www.newspapers.com/clip/31159286/palmer_st_bridge_august_21_1955/. https://en.m.wikipedia.org/wiki/Northampton_Street_Bridge
Even more impressive is the transcontinental railroad, one of the tunnels they dug out from both sides and met up in the middle. They were within an inch I think
I’d ask the same question about *tunnels*. You can’t even see where you’re headed.
IIRC there’s some tunnel connecting Manhattan with either New Jersey under the Hudson River or Brooklyn under the East River (I don’t remember what side) that was built in the late 1800s with two excavation teams from both sides that met in the middle with an error of less than 1 inch. I can’t get through my skull how this could be done at the time.
The original Huey P Long bridge in New Orleans has a 1.5′ “jog” in the roadway about 1/3 the way up the bridge. I suspect it was due to measurement errors. The lanes were super narrow, at 9′ wide, with no shoulders and most driver had to grip the steering wheel tightly while traveling the bridge, Especially if an 18 wheeler was next to you.
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