Durability + Design
Follow us on Twitter Follow us on LinkedIn Like us on Facebook Follow us on Instagram Visit the TPC Store
Search the site

 

D+D News

Main News Page


Report: CA Tower's Sinking Did Not Crack Window

Wednesday, October 24, 2018

More items for Good Technical Practice

Comment | More

A new report has dismissed the idea that the sinking of San Francisco’s Millennium Tower is what caused a window to crack on the 36th floor.

Architecture and engineering firm Allana Buick & Bers released a report last week that concluded that the crack—which appeared over Labor Day weekend—was caused by “exterior impact.”

What Happened

According to the San Francisco Chronicle, the crack was discovered around 2:30 a.m. on Sept. 1, when the unit owner awoke to a “massive” banging sound.

Hydrogen Iodide, public domain, via Wikimedia Common

A new report has dismissed the idea that the sinking of San Francisco’s Millennium Tower is what caused a window to crack on the 36th floor.

“This sound was so massive in scale, it sounded like a huge, thick vault door had just slammed shut,” the homeowner said, noting that over the next 30 minutes it sounded like the glass in the window was splintering.

The incident sparked widespread concern that the tower’s infamous settling issue was to blame for the crack, and that more damage would occur.

The tower has sunk at least 18 inches and tilted 14 inches to the west and 6 inches to the north since it opened in 2009. The 58-story tower sits on a 10-foot-thick mat foundation, held in position by 950 reinforced concrete piles that are sunk 60 to 90 feet into clay and mud but do not reach the bedrock, which is what the settling is attributed to.

To fix the leaning issue, engineers are suggesting boring 275 to 300 steel and concrete “micro piles” down to bedrock, only on one side of the building at a time, starting with the west side. Once the structure is stabilized, the east side would be allowed to sink until the building straightens itself. Then, micro piles would also be driven into that side, preventing the structure from sinking any further. Repairs are slated to take two to five years.

The Report

After Buick & Bers filed its report, the city’s Department of Building Inspection also had an independent engineer from Standford University, professor Greg Deierlein, review the report.

Deierlein concluded that there was no reason to further investigate, but did advise that the overhead scaffolding that has since been installed around the window to protect the street below remain intact until the window is replaced, which has a deadline of Nov. 18.

The building’s management has said that a new window has been ordered from Shanghai, so the replacement likely won’t take place until next month. The window, once removed, will also be inspected, and a visual inspection of all similar windows in the tower is to be completed by Dec. 21.

   

Tagged categories: Condominiums/High-Rise Residential; Health and safety; Safety

Comment from Andrew Piedl, (10/24/2018, 8:43 AM)

Gremlins?


Comment Join the Conversation:

Sign in to our community to add your comments.

Advertisements
 
Novatek Corporation
 
Novatek Portable Air Filtration Systems
 
Air Scrubbers/Negative Air machines for restoration, abatement, dust & odor control, hazardous contaminant removal from job sites to clean rooms and hospitals. Portable, affordable!
 

 
Shield Industries, Inc
 
FireGuard® E-84 Intumescent Coating - Shield Industries, Inc
 
Trust the certified protection of the industry’s most innovative intumescent coating FireGuard® E-84 to provide you with the 1 and 2 hour fire ratings you need.
 

 
Keim Mineral Coatings
 
Mineral Silicate Paints + Stains Fuse to Concrete
 
• Forms permanent chemical bonds
• Becomes part of the concrete
• Will never peel
• Looks completely natural
 

 
 
 

Technology Publishing Co., 1501 Reedsdale Street, Suite 2008, Pittsburgh, PA 15233

TEL 1-412-431-8300  • FAX  1-412-431-5428  •  EMAIL webmaster@durabilityanddesign.com


The Technology Publishing Network

Durability + Design PaintSquare the Journal of Protective Coatings & Linings Paint BidTracker

 

© Copyright 2012-2018, Technology Publishing Co., All rights reserved