SF Tower settlement Part III 18

[dik]

thread815-412357
thread815-470048

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

-Dik

 

[epoxybot]

If I recall correctly, the Millennium Tower's original EOR, DeSimone Consulting Engineers favored the LERA/ENGEO internal (symmetrical pile) 'upgrade'.

One might question whether the project's classification as a seismic 'voluntary upgrade', which allowed a host of other building code metrics to be avoided; still remains valid.

SGH was the waterproofing consultant during the tower's design and were involved with the choice of the waterproofing admixture for the 5-level, underground parking, in lieu of more traditional waterproofing schemes. Water leaks, unlike the sinking & tilting, were not something the Millennium Partners run HOA (up until 2014), could allow to go unaddressed. Thus SGH was active on 'issues' regarding the tower for some time before the tilting & sinking became public. Most of the water leak problems are of course at the tower/podium interface.

The symmetrical pile upgrade was largely an MP-free, HOA endeavor, which, had it proceeded; would have possibly removed Millennium Partners from having command & control of information related to the tower's construction. Any review of presentations & articles regarding the tower by SGH, shows they have religiously avoided revealing any data recorded during the tower's construction, other than what was advantageous to MP.

 

[dik]

I'd never consider the project as such a classification... It's a design error 'fix'.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[epoxybot]

Dik - I just came back to CORRECT the post. It was classified as a 'Voluntary' 'Upgrade'.

 

[spsalso]

It's been awfully quiet over there for awhile. No Hamburger. No Peskin.

What are you kids DOING over there?



spsalso

 

[dik]

epoxybot... fixed mine, too.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Walnuts]

epoxybot, dik, actually it is both. It is a voluntary seismic upgrade. That is specifically described in the San Francisco regulations. According to Hamburger it is not a seismic upgrade, but San Francisco does not have a category called (laughable) voluntary foundation upgrade. I have heard that Neville Pereira of DBI has said that when he first appeared on the scene he did not understand why it had been permitted as a voluntary seismic upgrade, but it is the only thing on the books that allows you to skirt the current code requirements.

 

[dik]

I would think that by 'skirting' current code requirements, they could be opening themselves to a bunch of litigation.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[spsalso]

But if the "skirting" is acceptable to local authorities, that causes a problem with the lawsuits. The capitalists can say that the City accepted the proposal. You likely will have to sue them (the City), too. And so you will have to also confront the might of the Great State of San Francisco.

They accepted the reasoning, did they not, in granting approvals?



spsalso

PS: San Francisco likes "the City" to be capitalized (not sure about the "t"), because it's so very important.

 

[Just Some Nerd]

but it is the only thing on the books that allows you to skirt the current code requirements.

Classic example of engineering gone wrong - doing what is technically allowable by finding a loophole, rather than what is actually correct.

----------------------------------------------------------------------

Why yes, I do in fact have no idea what I'm talking about

 

[TugboatEng]

Wait for ab emergency declaration to be made so that no laws apply anymore.

 

[Alistair_Heaton]

Our far does it have too go before it gets to that emergency point? Presume there is a cut out angle when it will have to start demolishing it.

 

[dik]

With a seismic event and the type of soil, it may not be that gradual, I suspect.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[epoxybot]

Millennium Tower Fix to Reverse About Half the Tilting Triggered During Project, Model Predicts

Two new reports from NBC Bay Area's Jaxon Van Derbeken.

 

[spsalso]

The Tilt-O-Meter says the building is still tipping. More. And more.

I assume this "rebound" will take effect after they finish the work. Apparently in the Spring. Which lasts until June 21.

The big thing here is that they say they won't right the building. I definitely saw drawings showing hydraulic jacks in there, somewhere. Seems to me you just keep putting shims in and readjusting the jack until the build is vertical again.



spsalso

 

[Walnuts]

Ha ha ha! The load transfer to the new perimeter piles is applied through hydraulic jacks but that is to limit the loads applied to both the mat and the mat extensions (so they don't crack up) and the piles (so they don't buckle). But the building is far too heavy for the jacks to actually lift it! Likely what is going to happen is that in order to limit the load in the jacks they will have to back off the load frame and the build will continue to settle and tilt. No-one knows for sure - it is impossible to calculate accurately - but at least some pretty smart people think that there will be even less recovery of tilt than the design team is predicting and continued settlement. Part of the thinking is that everything this design team does goes wrong and that is not going to change!

 

[spsalso]

"But the building is far too heavy for the jacks to actually lift it!"


Hmmmm.

First, you only have to lift half of it: 686,000,000 lbs / 2 = 343,000,000 lbs

Then you assume a typical hydraulic pressure of 10,000 psi

343,000,000 / 10,000 = 34,300 square inches

If you use a jack with a 5" diameter piston, it is 20 square inches

So you need 1715 jacks

If we assume the jack base is 1 foot square, then you can get 100 in the length of the short wall of the tower (I believe it's about 100 feet long).

1715 / 100 = 17 rows of jacks, 100 in each row

Of course, you probably would also want so in part of one of the long walls. So put jacks under 100' of THAT wall, too.

Then you only need 9 rows.




spsalso

 

[Walnuts]

Ha ha! But what do the jacks push against? !8 24-inch diameter pipe piles?

 

[spsalso]

I guess they'd have to. There would have to be "adapter plates" above and below the jacks.

It appears they did not design in any way to do something like this, even though it appears feasible.

A person could wonder why they didn't bother. Especially if they owned a unit in the building.


spsalso

 

[TugboatEng]

40kpsi jacks are standard fare in the power transmission sector. We use them for fastener tensioning and coupling mounting.

 

[dik]

... so you only need 400 or 500 jacks. That's an improvement?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik