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SF Tower settlement Part II
3

SF Tower settlement Part II

SF Tower settlement Part II

(OP)
"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"

RE: SF Tower settlement Part II

3
Powerpoit/PDF presentation "The Millennium TowerSettlement, Tilting and Upgrade"
by Ronald O. Hamburger, S.E., SECB of Simpson, Gumpertz & Heger.
University of Kansas 5, March 2020
Link

RE: SF Tower settlement Part II

This is a silly question, but if it has sunk 16" how are all the entrance doors still working or if the entrance doors and thresholds are also sinking with the foundations - surely there would be a very noticeable ramp/step down into building?

Explain!

Brian,

RE: SF Tower settlement Part II

I would imagine the building isn't slipping into the Earth like a peg in a hole... there has to be some form of slumping along the edges. Maybe not enough to completely eliminate a threshold tripping point, but surely the surrounding sidewalk is tilting somewhat.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: SF Tower settlement Part II

There's serious damage to the sidewalks around the building.

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

-Dik

RE: SF Tower settlement Part II

I would like to see settlement and tilt info newer than 3 years old. Retrofit piling was supposed to start in November but no news on that. I wonder if delays will allow the project to pass the fix-it stage.

RE: SF Tower settlement Part II

In July the press reported the tower had sunk a total of 18 inches and was tilting 14 inches. So about 2 inches since the fall of 2016, if I recall correctly. The powers that be, likened the slowing of the sinking to the secession of work on the White Elephant (TJPA) next door.
Serendipitously, the mat foundation extends beyond the only entry/exit affected by the sinking.

Correction: The sinking of 18" & tilting of 14" are from 2018, which according to another article from July 2020, was the last time these factors were made public.

The only entry/exit points affected are the lobby entrance on Mission St. (photo) and the access points on 3 levels between the tower and the podium structure. So the patio, the indoor pool level and basement/garage access. These last three have been a bit of a terror for the HOA & Millennium Partners, as they must be Handicap Accessible. Of course the SF Dept of Building Inspection has been very vigilant of this process, not wanting to be found lacking, as they were from the start.

RE: SF Tower settlement Part II

So does the surface drainage still work? Does water run back into the building?

RE: SF Tower settlement Part II

There have been modifications made since to the entry. The entry from the planter to the doorway has been replaced.

RE: SF Tower settlement Part II

Nice Hamburger report... did they start the remediation on May 1 of this year? It's nice to have loading going down to bedrock... until it does, is there a chance for a seismic event to liquify the soil beneath the building? There seems to be no mention of what will happen if they just leave it and don't repair... no prolonged time sensitive curves showing the increased settlement and/or tilt.

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

-Dik

RE: SF Tower settlement Part II

Thanks... I'd wait until the problem was fixed before signing off on anything... what if the repair is never undertaken or if it doesn't work?

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

-Dik

RE: SF Tower settlement Part II

Quote (Dik)

... until it does, is there a chance for a seismic event to liquefy the soil beneath the building?

The mat foundation sits on young bay mud, below the non-engineered fill layer, which is from 17 to 42 feet thick, across the whole of the site. It would require a sustained, high magnitude earthquake to mobilize the QYBM.
I think the fun really begins when they remove the CDSM shoring wall on Fremont & Mission St and the Play-Doh starts production.

The headline of the SFist article, posted by Jay, is misleading, as most of the $30 million, ascribed to SF Taxpayers will be borne by US, State and Bay Area Taxpayers, including $1 dollar from every vehicle that crosses the SF-Oak Bay Bridge, ticket fares from CalTrain riders & Alameda-Contra Costa bus riders.

The people of SF & SF Government are let off the hook quite nicely. SF Govt's contribution to settling the Millennium Tower litigation was waiving the $3.10/sf/yr sub-sidewalk rental fee for the long-term right of the Millennium HOA to make incursions into the public right of way (Below Sidewalk). About $8500/year.

RE: SF Tower settlement Part II

Screen grab captured from a YouTube video Dec. 10m by a package delivery guy who skateboards (Electric) around SF.
It looks like they are just getting started.

RE: SF Tower settlement Part II

thanks... I was thinking for the settlement to have occured so quickly that there must be a fair flow... maybe not.

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

-Dik

RE: SF Tower settlement Part II

Quote (Dik)

I was thinking for the settlement to have occured so quickly that there must be a fair flow... maybe not

The tower settlement or the litigation settlement?

RE: SF Tower settlement Part II

they could both go on for decades...bigsmile

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

-Dik

RE: SF Tower settlement Part II

From the SkyscraperPage Forum, a couple of photos from Feb. 8, 2021
Link

In these photos they are currently driving soldier pile & lagging shoring.

RE: SF Tower settlement Part II

Now if they had just had this technology in Pisa back in the 12th century...

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: SF Tower settlement Part II

What are the odds this’ll work?

RE: SF Tower settlement Part II

Quote (Now if they had just had this technology in Pisa back in the 12th century...)


Most people aren't aware that Pisa is 'curved'... the masons built it plumb as it settled... building a 'curve' into the structure.

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

-Dik

RE: SF Tower settlement Part II

Quote (What are the odds this’ll work?)


They need to take it to bedrock... They've looked into it... but I have a concern about liquifaction in case of a seismic event.

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

-Dik

RE: SF Tower settlement Part II

Quote (Dik)

They need to take it to bedrock..

Isn’t the rest of it floating in soil?

RE: SF Tower settlement Part II

It's interesting, there is quite a bit of settlement in SF. My friends working as operating engineers in SF have had to renew connections due to utilities due to the large amount of settling experienced. Much of the city is built on fill. The fact that Millennium tower has favored a side to settle on could be why the Trans Bay Tube constructors are interested in settling themselves.

RE: SF Tower settlement Part II

My understanding... and the reason for the settlement... I don't know how you address the difference in stiffness between the two types of foundations.

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

-Dik

RE: SF Tower settlement Part II

San Francisco has some of its utilities resting on piles to prevent them from settling with the fill. When you see a blue topped fire hydrant, it is part of the emergency/cistern based fire fighting system established after the 1906 earthquake. All of that system rests on piles.

Mission Bay is the one of the newest development ares in SF and they have a huge problem with ground settlement.
Link

Attached is a pile map showing the depth of piles driven. The white piles are cut short, the blue piles are Re-strike quality piles. There are more (re-strike) piles on my map than listed by Treadwell & Rollo, as I added all piles with less than a hundred blows in the last 5 feet and then went through the list and added some piles with descinding blow counts; which appeared to have blown through the crust layer between Colma/Marine sand layer & a Marine Mud layer. It is the short cut piles that will prove the most resistant to the scheme proposed by SG&H.

RE: SF Tower settlement Part II

Why can't I see my attachment?

RE: SF Tower settlement Part II

Quote (epoxy)

Mission Bay is the one of the newest development areas in SF and they have a huge problem with ground settlement.

What is this area built on? Is it some sort of reclaimed land? How has it settled so much so quickly?

RE: SF Tower settlement Part II

Yes, Mission Bay is all fill. There is an interesting film "Erased Landscape" about the filling in of Yerba Buena Cove & Mission Bay. Link

RE: SF Tower settlement Part II

Link to the Engineering Design Review Team's Comment Log for the perimeter pile upgrade.

RE: SF Tower settlement Part II

The last comment is nearly 2 years old... anything more recent?

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

-Dik

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