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Comment by michaelt | Hacker News Reader

  sometimes they’re loosened all the way
  to “finger tight,” sometimes a few pins
  are removed ahead of time
  [...]
  “It saves time, which equals money.”

I'd have thought the time it takes the supporting crane to lower the top section to the ground would have been greater than the time it takes to remove eight bolts. After all, presumably the guys doing this for a living have the best tools available.

Does anyone know why removing the bolts is so slow? Or is the supporting crane actually really fast?

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Thinking about it, they need to remove eight bolts per section, then the section itself, then eight bolts for the next section, and so on. I could have expected them to save time by removing the bolts of the second top section in parallel to the supporting crane removing the top section, but removing the bolts of all sections only makes sense when the supporting crane is actually faster than the bolt-removing guy/team.

Something else might be going on -- maybe they did not want the workers who were removing the bolts to wait for the supporting crane and sent them home to save on wages or gave them other work to do.

My first guess was that you have to climb back down to the ground between each section being removed, for safety reasons (don't get hit by a swinging section of crane). But in that case you'd still have to climb to remove the last two bolts, so it doesn't really save anything.

It might be along the same lines as your mom telling you to do the washing up now rather than later when you need the dishes.

It's the same effort now and later, but putting it off makes you look lazy.

Someone was probably keen to impress the boss and say "Look, we've removed all the pins so that cranes ready to come down. Nothing else to do now! 2 days ahead of schedule!".

I would guess it saves crane time for the supporting crane. If the bolts are loosened before the supporting crane begins operating, the total start to finish crane time can be less.

Of course, the tower's resistance to overturning moment is reduced during that time - to what appears to be fatal results in this case. Not worth it.

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