SF Tower settlement Part II 18

[1503-44]

"Appreciation has dropped to 2%"
Well that's less than inflation, but more than interest rates.

Although as I said, probably nobody bought in for either of those reasons.

“What I told you was true ... from a certain point of view.” - Obi-Wan Kenobi, "Return of the Jedi"

 

[dik]

The expression in these environs is, "done like a turkey."

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

I suspect the structure has some serious seismic issues. I'm not big on seismic, but the building is tall and is founded, rather shallowly IMHO. A seismic event is relatively unpredictable. In the event of one, there could be some serious loss of life for those in the building as well as those on the ground. For this reason alone, I would think that the city of San Francisco should be looking for an immediate response to the 'leaning tower' problem. They need to get some serious and good geotekkies out on site, immediately.

Else, California, could outdo Florida.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Red Corona]

The 'fix' of putting piles down to the bedrock only in one corner of the building certainly seems like it will give it a pretty serious 'seismic issue'. The whole concept of building large buildings on partially consolidated clay seems pretty dodgy in the first place, but presumably the engineers have considered that for all the other buildings around there.

> I will speculate that the Engineers who designed the drain system did not leave any "slop" for correcting these problems.

When you're trying to put utilities into a building you're going to assume the building is a fixed point, and pack things in as tightly as you can. I can't really blame the internal engineering for not allowing for the building floors no longer being horizontal!

 

[spsalso]

"...pack things as tightly as you can."

Yeah. What could go wrong?


spsalso

 

[apper.42]

tightly as you can."

Just like a junction box that's too small.

 

[Red Corona]

> What could go wrong?

I dunno but it's almost certainly the next guy's problem, not mine!

 

[hamjohn]

Link to 301 Mission Street - Millennium Tower Retrofit Documents:

https://sfdbi.org/reports

 

[spsalso]

Link to 301 Mission Street - Millennium Tower Retrofit Documents:

https://sfdbi.org/reports

A person could wonder why the contents of reports 11, 13, 15 are all copies of report 9.

And a person could wonder why the contents of reports 18, 20, 21 are all copies of report 19.


Are reports ending in 9 so remarkably important that they should be shown repeatedly, instead of the correct ones?




spsalso

 

[hamjohn]

Pile Test Likely for Settling Millennium Tower

https://www.enr.com/articles/52532-pile-test-likely-for-settling-millennium-tower

 

[hamjohn]

Millennium Fix Engineers Want New Test Pile Installed

https://www.msn.com/en-us/news/tech...pile-installed/ar-AAP1eu4?ocid=BingNewsSearch

 

[epoxybot]

I'm stumped about the Too Big concept. The auger fits inside the casing. What am I missing?

 

[Walnuts]

I was also stumped at first but then I discovered that the auger does not go inside the casing - at least not for the 36-inch casings. They only used that big auger to drill the first 20 feet of so so that they can set the first length of casing. Then they push (crowd) the casing down, attach new casing lengths with a special fitting of some kind, and use a bucket to remove the top of the plug. I have no idea how they judge what to remove and how much plug to leave in, but the ERDT has suggested leaving a longer plug and making sure that there is a positive hydraulic gradient. I thought all this was elementary. I know less about the 24-inch casings but I think they admit to over-drilling them, so I guess Legacy are going to Home Depot to buy a slightly smaller auger, or whatever it is, for that.

 

[hamjohn]

Brief look of drilling operation

https://www.nbcbayarea.com/investig...x-of-san-franciscos-millennium-tower/2639941/

 

[hamjohn]

Page 11 of latest survey report shows the tower has leaned 0.5 inch from 8/22/2021 to 9/20/2021. All work stopped on 8/22/2021.

https://sfdbi.org/sites/default/files/20210929 Monitoring Report 022.pdf

 

[Walnuts]

Well, all work except drilling some soil borings at the N-W corner. Even that seems to have triggered a bit more settlement and tilt!

 

[epoxybot]

So far, the only use I have found for this chart is noting Mission Street Development/Millennium Partners/Paul Hastings LLP/SG&H/Slate efforts to continue to disguise the construction phase as problem free.

 

[dik]

Is that leaned 1/2" or settled 1/2"... just curious.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[hpaircraft]

I like the prominent leaning arrow in the Slate logo. They were made for this project. "Better Slate than never!"

 

[hamjohn]

Currently, the tower is tilting 22.5 inches towards Fremont and 9 inches toward Mission. Under Hamburger’s analysis, the building can tilt 6.5 inches more to reach the 29-inch threshold on Fremont and three inches to reach the 12-inch Mission threshold, and still remain seismically “safe and stable.”

https://www.nbcbayarea.com/investig...ismic-safety-and-stability-threshold/2674460/

 

[Walnuts]

In response to epoxybot, it has been "tared out". For instance, there have been various reports of up to 6 inches dishing of the mat during construction but these have basically been buried. Hamburger mentioned that in his first ever draft report and then it disappeared for a long time. However, it has resurfaced in some of his recent comments in the comment log.

In response to hamjohn, the lateral roof deflections were about 16 inches to the west and 7 inches to the north when they started the PPU, so in each case they have so far used up about half of their own margin of safety. One of many big questions is why did they keep going so long?