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N. Prabhakar General Sponsor
Joined: 25 Apr 2009 Posts: 474
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Posted: Sat Nov 05, 2016 6:17 am Post subject: |
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Dear Er. Pandyaji,
Thanks for the latest information on the settlement and tilt problems of the Millennium Tower in San Francisco.
Certainly, the main problem is in having foundation with friction type piles in muddy type of soil down to 80 ft only, instead of taking them down to rock level at 200 ft. This problem has been later compounded by dewatering from the soil of the nearby site.
This sort of problem has been there in India too, particularly in areas where ground water level has been lowered due to digging of large number of bore wells in the area. But these are less known to the public through the media as the suffered buildings are of smaller heights. The following links give article on the subject which may be of interest to you:
http://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=2101&context=icchge
http://www.igs.org.in/annual-lecture/Annual%20Lecture%202012.pdf
With best wishes,
N. Prabhakar
Chartered Structural Engineer
Vasai (E), Pin 401 208 |
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VPandya General Sponsor
Joined: 09 Nov 2009 Posts: 842
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Posted: Tue Nov 29, 2016 5:59 pm Post subject: " Latest on “58 Story Leaning/Sinking Tower of San Francisco , USA " |
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Dear Engrs. Prabhakarji/Dr. Subramanianji,
Latest on “Leaning Tower of San Francisco “ . From ENR ( Engineering News Record), dated: 28-11-2016 :
Satellite Image Analysis Shows San FranciscoTower Sinking at a Steady Rate. (Think of using space satellites for this work) :
SAN FRANCISCO (AP) — Engineers in San Francisco have tunneled underground to try and understand the sinking of the 58-story Millennium Tower . Now comes an analysis from space.
The European Space Agency has released detailed data from satellite imagery that shows the skyscraper in San Francisco's financial district is continuing to sink at a steady rate — and perhaps faster than previously known.
The luxury high-rise that opened its doors in2009 has been dubbed the Leaning Tower of San Francisco . It has sunk about 16 inches into landfill and is tilting several inches to the northwest.
A dispute over the building's construction in the seismically active city has spurred numerous lawsuits involving the developer, the city and owners of its multi million dollar apartments.( Origional cost of the project USD 350 Million).
Engineers have estimated the building is sinking at a rate of about 1-inch per year. The Sentinel-1 twin satellites show almost double that rate based on data collected from April 2015 to September 2016 .
ENR WEB-LINK :
http://www.enr.com/external_headlines/story?region=enr&story_id=Yktfp9naptlr4_opOTqPGg9wk8gEG9YqlPGZ0hAGhytFLX4x5e8m5EbpfoEAYhR8k3_98Kq9pZuTOgac6pOpbtZPsq-VUQE_xHL8dwat_c-36bCm0hWJCgGeiC_MxIcz04tzFo7PH_2-wCDxvHrv4BnKRN6NFgy1Ax9OyDfXKxc*
Regards.
VasudeoPandya P.E.
StructuralEngineer
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N. Prabhakar General Sponsor
Joined: 25 Apr 2009 Posts: 474
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Posted: Wed Nov 30, 2016 1:11 pm Post subject: |
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Dear Er. Pandyaji,
Thanks for posting the latest information on the Millennium Tower in San Francisco.
In my opinion, more than the uniform settlement of the Tower which initially started due to a improper foundation over a poor subsoil condition, it is the tilting of the Tower later by several inches, after lowering of ground water that took place during the excavation work of nearby Tranbay Terminal, is of more concern against overall structural stability.
One of the options to solve the problem of tilt is to retrieve the ground water condition below the Tower to the same condition that existed prior to doing excavation work at Tranbay Terminal. I don't know whether it is easier to say than done. I am sure, America having great Geo-Technical brains among their Engineers will solve it.
With best wishes,
N. Prabhakar |
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VPandya General Sponsor
Joined: 09 Nov 2009 Posts: 842
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Posted: Thu Apr 04, 2019 3:26 pm Post subject: NOW 58 STORY LEANING TOWER OF NEW YORK : |
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Desr Sefi Engrs ,
FROM : ASCE SMART BRIEF , 4th April , 2019 :
NOW 58 STORY LEANING TOWER OF NEW YORK :
FOUNDATION FAILURE , SHOULD HAVE BEEN PILE FOUNDATION TO BED ROCK BUT FOR REASONS OF COST CUTTING ON FOUNDATION , IT WAS NOT DONE :
Lawsuit claims faulty foundation caused 58-story tower to lean
A lawsuit over an under-construction, 58-story condo building in New York City argues that developer Fortis Property Group failed to drive support pilings into the bedrock, causing the tower to lean 3 inches to the north. "Soil improvement" was used instead, according to former site contractor Pizzarotti, and its lawsuit claims that work should stop until a remedy is found.
A 670-foot, 58-story luxury condo project that is among the city’s tallest waterfront towers is leaning three inches north because of a faulty foundation, according to recently filed court documents.
The embarrassing snafu at 161 Maiden Lane deals another blow to a high-profile seaport project that has attracted deep-pocketed buyers for its floor-to-ceiling views, but has been beset by problems.
The project’s original contractor, Pizzarotti, has accused developer Fortis Property Group of skimping on the building’s foundation system, electing to go with a cheaper but less reliable method, according to a lawsuit filed last month in state Supreme Court. Instead of driving support piles down into bedrock, the suit charges, Fortis allegedly chose to use "soil improvement" methods to shore up the construction site; Pizzarotti began building on this foundation, only to notice the building begin to "exhibit a noticeable leaning condition."
The complaint further contends that the building, which has already topped out, is still moving and that due to safety issues, “the work on this project should not proceed any further” until the building's condition is evaluated.
Web-Link :
Gothamist (New York) (4/3)
Regards.
Vasudeo Pandya P.E.
Structural Engineer |
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VPandya General Sponsor
Joined: 09 Nov 2009 Posts: 842
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Posted: Thu Aug 29, 2019 2:00 am Post subject: 58 STORY SAN FRANCISCO LEANING TOWER GETS AN EXPENSIVE $100.0 mil FIX |
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Dear Sefi Engrs ,
58 STORY SAN FRANCISCO LEANING TOWER GETS AN EXPENSIVE $100.0 mil FIX.
Latest from ASCE SMART BRIEF , AUG . 28th , 2019 .
Panel green-lights plan to shore up Millennium Tower
A four-person panel led by Stanford engineering professor Gregory Deierlein has approved a proposed $100 million fix to San Francisco's sinking and tilting Millennium Tower. The project calls for the installation of 52 circular, steel-reinforced concrete piles that will transfer a portion of the building's weight from its current foundation to bedrock roughly 250 feet below ground.
Web-Link :
https://www.sfchronicle.com/bayarea/article/Expert-panel-endorses-plan-to-stabilize-SF-s-14382917.php
Regards.
Vasudeo Pandya P.E.
Structural Engineer |
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