The weight of buildings and the raising of Chicago | Hacker News Reader

The weight of buildings and the raising of Chicago

leancrew.com

45 pointsfanf29 comments

Wait till folks find out about engineers reversing the flow of the Chicago River [1] in 1900.

[1] https://theculturetrip.com/north-america/usa/illinois/articl...

Largest earth-moving project in North America at the time and the techniques developed and engineers trained on it would later be used to dig the Panama canal.

How do you jack a building up? For example how do you get that initial amount of space to put a jack underneath it? Do you excavate and somehow avoid a cave in or the building shifting?

I was thinking about this as well. I assume you leave the foundation in place and jack up the structure. So you would remove sections of the structure to place a jack of some kind and then once enough jacks were in place crank them all at once.

Exactly, any sane structure is built with some redundancy so you should be able to temporarily remove a column or piece of wall to install the jacking equipment and then do the job.

For the tokyo station building, they simply lifted the building a bit and then placed it on seismic isolators. Can be seen on page 14 of this: https://www.ejrcf.or.jp/jrtr/jrtr61/pdf/6-15_web.pdf

Or for the Kansai International Airport the huge terminal building was built on jacks from the start the artificial island it was build on settles at an unequal rate: http://www.kansai-airports.co.jp/en/efforts/our-tech/kix/sin...

They measure the different parts settling and then have a bunch of guys that will go to the affected section and jack the columns appropriately.

They cut holes in the cement foundation and slide beams across the entire house, then lift it up. Back trailer under house, through another large hole cut in the foundation, lower house onto trailer and drive away. When I was a kid, I watched an entire neighborhood get moved when a Walmart got built across from my grandparents. Moving the houses was some kind of give back, after citizens sued for years trying to prevent it.

Build temporary supports. Gain access. Build more supports, temporary and permanent. Jack it up as you go.

House movers can do cool tricks like building a raft out of beams, under a house and without moving the house. then the raft is lifted and the house never subjected to too much stress.

On a (somewhat) related note: Jack-Up Project Saves Sinking North Sea Rigs (https://www.nytimes.com/1987/08/19/business/jack-up-project-...)

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