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SF Tower settlement Part III 18
- Thread starter dik
- Start date
Millennium Tower Fix Monitor Sidelined to Analysis Role
- Thread starter
- #3
From that article:
"Seven days after that memo, fix designer Ron Hamburger notified city officials – in a Nov. 30 letter – that “settlement monitoring indicates that no additional settlement or tilting occurred as a result of this 24-inch pilot installation.” He notified the city that the Dan Brown firm would no longer be present during upcoming testing. Although acknowledging that amounted to an exception to the agreed-to provisions of the testing program, Hamburger said the city’s own appointed design review panel “does not believe this is necessary.”"
I don't know what was agreed to, but oversight for any remedy should be in place. SF politics at play?
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
"Seven days after that memo, fix designer Ron Hamburger notified city officials – in a Nov. 30 letter – that “settlement monitoring indicates that no additional settlement or tilting occurred as a result of this 24-inch pilot installation.” He notified the city that the Dan Brown firm would no longer be present during upcoming testing. Although acknowledging that amounted to an exception to the agreed-to provisions of the testing program, Hamburger said the city’s own appointed design review panel “does not believe this is necessary.”"
I don't know what was agreed to, but oversight for any remedy should be in place. SF politics at play?
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
Engineers are proposing a new fix for the sinking, tilting Millennium Tower that they hope will avoid exacerbating the building’s settlement like during prior efforts.
- Thread starter
- #6
![[lol]](/data/assets/smilies/lol.gif "[lol] [lol]")
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1
- #7
Now I realize I'm only using arithmetic, instead of some higher math. So you guys should like maybe do some sort of analysis on the following:
How to put it?
52 / 18 = 2.8888...
We'll call that 2.9, to continue to avoid the higher math. That would appear to be the new supported weight per pile, compared to the old (52) quantity.
If the Old Piles could hold up 800,000 pounds each, then my calculations:
2.9 X 800,000 = 2.32 million pounds.
The amount the New Piles would have to hold up. Individually.
Correct me if I'm missing something, but isn't 2.32 (million) a whole lot bigger than the 1 (million) that is mentioned?
Perhaps they're going to lighten the building? Maybe restrict the number of pianos in each unit?
Or looked at another way: if the old piles were needed to hold up 52 X 800,000 pounds, then their total uppicity would be 41.6 million pounds. The new proposed piles can each hold up 1 million pounds. That's 18 million pounds.
41.6 - 18 = 23.6 million pounds to be held up with something yet to be described. Luck? Hot air? A hot air balloon?
spsalso
"The required construction is neither complex nor unusual." Ron Hamburger
How to put it?
52 / 18 = 2.8888...
We'll call that 2.9, to continue to avoid the higher math. That would appear to be the new supported weight per pile, compared to the old (52) quantity.
If the Old Piles could hold up 800,000 pounds each, then my calculations:
2.9 X 800,000 = 2.32 million pounds.
The amount the New Piles would have to hold up. Individually.
Correct me if I'm missing something, but isn't 2.32 (million) a whole lot bigger than the 1 (million) that is mentioned?
Perhaps they're going to lighten the building? Maybe restrict the number of pianos in each unit?
Or looked at another way: if the old piles were needed to hold up 52 X 800,000 pounds, then their total uppicity would be 41.6 million pounds. The new proposed piles can each hold up 1 million pounds. That's 18 million pounds.
41.6 - 18 = 23.6 million pounds to be held up with something yet to be described. Luck? Hot air? A hot air balloon?
spsalso
"The required construction is neither complex nor unusual." Ron Hamburger
- Thread starter
- #8
I don't have a whole lot of confidence in what they are doing. It's far beyond me geotechnically, and I have no idea of how to address the seismic issues.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
SF Business Times: "Less is more: Engineers behind Millennium Tower fix have a new strategy"
New calculations show piles can bear more weight than was previously known — an estimated 1 million pounds, per Hamburger’s letter, up from 800,000. Crews will be able to accomplish the objectives of the previously planned retrofit with the reduced number of piles, Hamburger wrote, though he noted that the building’s tilt would not be corrected as much as had been previously predicted.
There are new photos on [URL unfurl="true"]http://lbkarp.com[/url] - The 3rd to last photo shows a center bar in the pile much larger in diameter than the #18 high strength threaded bar previously proposed.
The Dan Brown & Associates letter from 23 November 2021 is also at lbkarp.com.
SG&H was the waterproofing consultant for the Millennium Tower project and the cracking in the bottom levels of the parking garage, immediately adjacent to the tower/podium shoring wall, will likely remain a chronic problem for the Millennium HOA. I'm quite certain the main water leakage/cracking is in the north & west walls of the lower parking levels. The parking garage walls incorporated an integral waterproofing admixture.
The tower/podium shoring wall in this area has two sections where the CDSM shoring wall has soldier piles at 2.5 ft OC. This location was troublesome early in the project, with water seeping into the excavation while the tie-back work was going on.
Beginning in Nov-2006 Surveyor, Martin M. Ron Assoc. began monitoring the Trestle erected to facilitate excavation of the Podium/Mid-Rise. From Nov-2006 to Jun-2007(time letter was written) they recorded continuing uplift of the trestle of 1-7/8 to 2-1/4 inches across the trestle.
I'm not sure how much basal heave is acceptable but the construction scheme of tying the tower to the shoring wall certainly complicates things. Then there is the uplift of the Mid-Rise on the corner of Mission St. & Beale St., as shown in an NBC image from late 2016. The uplift of the Mid-Rise was just noticeable in Apr 2011 (Google StreetView) and continues slowly over time. It currently looks to be about where it was in 2016.
The tower and the shoring wall are just a large shovel.
New calculations show piles can bear more weight than was previously known — an estimated 1 million pounds, per Hamburger’s letter, up from 800,000. Crews will be able to accomplish the objectives of the previously planned retrofit with the reduced number of piles, Hamburger wrote, though he noted that the building’s tilt would not be corrected as much as had been previously predicted.
There are new photos on [URL unfurl="true"]http://lbkarp.com[/url] - The 3rd to last photo shows a center bar in the pile much larger in diameter than the #18 high strength threaded bar previously proposed.
The Dan Brown & Associates letter from 23 November 2021 is also at lbkarp.com.
SG&H was the waterproofing consultant for the Millennium Tower project and the cracking in the bottom levels of the parking garage, immediately adjacent to the tower/podium shoring wall, will likely remain a chronic problem for the Millennium HOA. I'm quite certain the main water leakage/cracking is in the north & west walls of the lower parking levels. The parking garage walls incorporated an integral waterproofing admixture.
The tower/podium shoring wall in this area has two sections where the CDSM shoring wall has soldier piles at 2.5 ft OC. This location was troublesome early in the project, with water seeping into the excavation while the tie-back work was going on.
Beginning in Nov-2006 Surveyor, Martin M. Ron Assoc. began monitoring the Trestle erected to facilitate excavation of the Podium/Mid-Rise. From Nov-2006 to Jun-2007(time letter was written) they recorded continuing uplift of the trestle of 1-7/8 to 2-1/4 inches across the trestle.
I'm not sure how much basal heave is acceptable but the construction scheme of tying the tower to the shoring wall certainly complicates things. Then there is the uplift of the Mid-Rise on the corner of Mission St. & Beale St., as shown in an NBC image from late 2016. The uplift of the Mid-Rise was just noticeable in Apr 2011 (Google StreetView) and continues slowly over time. It currently looks to be about where it was in 2016.
The tower and the shoring wall are just a large shovel.
If, as it seems to be the case from that photograph, the building is pushing up other structures at one side, it is not so much settling due to accelerated compaction and dewatering of the OBC, as rotating by mobilising the OBC. To my non-local eye words like settlement paint an altogether passive picture of what is going on.
- Thread starter
- #11
MacGyverS2000
Electrical
- Thread starter
- #14
23.6 million pound of uplift needed.
Uplift per balloon: .03 lbs
That ole arithmetic again:
23.6 million lbs (extra lift needed) / .03 lbs (upness per balloon) = 787 million balloons.
I LIKE it!!
This will make Hamburger not only the most famous structural/aeronautical engineer ever, but also establish him as a world class artist. And a very very cool guy.
It's almost too bad this building wasn't built in Buffalo: Billion Balloons over Buffalo
Wow!
spsalso
Uplift per balloon: .03 lbs
That ole arithmetic again:
23.6 million lbs (extra lift needed) / .03 lbs (upness per balloon) = 787 million balloons.
I LIKE it!!
This will make Hamburger not only the most famous structural/aeronautical engineer ever, but also establish him as a world class artist. And a very very cool guy.
It's almost too bad this building wasn't built in Buffalo: Billion Balloons over Buffalo
Wow!
spsalso
- Thread starter
- #16
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1
- #17
Milliontown
Geotechnical
expoybot said:
It appears from the other pictures the bar is also being used as the tremie to place the concrete, indicating it is hollow. A few pics from the website show a concrete pump hose running up the bar that is only present when the bar is being placed. I wonder if it has an equivalent cross sectional area to a #18
- Thread starter
- #19
![[ponder]](/data/assets/smilies/ponder.gif "[ponder] [ponder]")
This ENR article finally popped-up on Google/News "Engineer Proposes Slashing Scope of Millennium Tower Pile Upgrade"
It links to a letter to the HOA and also to SFDBI. The SFDBI letter confirms that the center bar is hollow and used for tremie placement of grout.
There is a layout of piles in various states of completion, as of August 21, 2021. I believe 3 more 24 inch piles have been done since. SG&H are suggesting 18 total piles but it could be 24 piles, depending on the EDRT.
The intial design of the piles called for a #18 center bar. Checking the EDRT Comment Log, the center bar was increased to 3 inches. No doubt hollow. The bar in the LB Karp photo, to my eye, looks larger than 3 inches.
It links to a letter to the HOA and also to SFDBI. The SFDBI letter confirms that the center bar is hollow and used for tremie placement of grout.
There is a layout of piles in various states of completion, as of August 21, 2021. I believe 3 more 24 inch piles have been done since. SG&H are suggesting 18 total piles but it could be 24 piles, depending on the EDRT.
The intial design of the piles called for a #18 center bar. Checking the EDRT Comment Log, the center bar was increased to 3 inches. No doubt hollow. The bar in the LB Karp photo, to my eye, looks larger than 3 inches.
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