Large skyscraper in SF that didn't get anchored to bedrock. Now the residents are sueing for them to fix it. Isn't it kinda' late ??
https://www.yahoo.com/news/san-franciscos-exclusive-millennium-tower-023751496.html
R.J. Schneider, post: 383921, member: 409 wrote: Large skyscraper in SF that didn't get anchored to bedrock. Now the residents are sueing for them to fix it. Isn't it kinda' late ??
That's what happens when you build a structure and fill it with attorneys.
I worked for a GC back in the day that had built a six story library at a local university. After a year the floors were sinking in the middle and pulling away from the walls. The university sued anybody that had ever touched the place.
After a review of the original contract it was discovered the university had only specified a standard loading, similar to an office building. Huge shelves of books apparently weigh a little more than usual. The architect and the GC were cleared in the suit. A structural consultant was hired to come up with a fix. After a couple of hundred thousand dollars the recommended fix was "should have put more steel in it when it was built".
It is an administration building today.
Here is a webcam of the transit site, turn the speed all the way down and view the full recording for an idea of the scope of work.
http://transbaycenter.org/construction-updates/construction-cameras/beale-camera
Contractor Response looks reasonable to me.
http://www.transbaycenter.org/uploads/2016/08/301-Mission-Press-Release-August-2016-FINAL.pdf
No problem.
Tear it down, start over, and do it right!
Oh, and blame the surveyor...
Paden's story of the building sinking in the middle reminded me of a story told to me over 40 years ago by a consulting civil engineer who also taught university courses in his spare time. His case involved a large single story building with a very broad footprint. His investigation found that under the entire building was a layer of highly expansive clay soil. Areas near the perimeter would swell normally as moisture from areas with rainfall would supply water to the soil not far from the perimeter. Meanwhile, the areas near the center of the structure were growing drier over time and shrinking.
He had them stick a garden hose through some opening in the floor near the center of the building so as to cause the clay to swell back to the pre-construction standard. He was paid quite well when they discovered how well his plan worked out.
Holy Cow, post: 383978, member: 50 wrote: ...He was paid quite well when they discovered how well his plan worked out.
Yep. The invoice read:
Sticking a garden hose under the floor - $1.00 Knowing where to put the hose - $99,999.00
paden cash, post: 383986, member: 20 wrote: Yep. The invoice read:
Sticking a garden hose under the floor - $1.00 Knowing where to put the hose - $99,999.00
What, he didn't charge for the hose?
From the article: "He reiterated the developers' blame for the tower's problems on the city's construction of an adjacent railway station, which they say removed ground water from beneath the Millennium Tower that caused it to sink and tilt."
That's always an important first step in keeping a multi-story structure from falling over; hire a butt load of attorneys to start slinging fresh baked culpability in every direction.
I'm surprised that nobody else noticed that the story stated that satellite images have confirmed that the building had settled .13' in 12 months.
If we can determine elevations on earth within .13' from images captured in space....why the heck don't we have much better national elevation grids?
I'm thinking the press got it wrong again.
Tommy Young, post: 384137, member: 703 wrote: What, he didn't charge for the hose?
Good thing the Surveyor didn't prep the invoice. He would have billed 2 crew hours and written off the hose and milage..
Without knowing the entire story, it seems that if an entire building is sinking fairly uniformly (16" without falling over), that installing 180 seven foot diameter piles to bedrock on just one side of the building might cause the building to tip away from the buttress foundation as it continues to settle, or at least potentially contribute to in moving in that direction?
I'm sure the buttress wasn't connected to the building, but it may affect the amount of available room for displacement of the soil as the structure settles?
R.J. Schneider, post: 383921, member: 409 wrote: Large skyscraper in SF that didn't get anchored to bedrock. Now the residents are sueing for them to fix it. Isn't it kinda' late ??
It ain't too late for the vultures to be on final approach. They even have their own website. (not amazing) 😉
"NEWSLETTER FOR MILLENNIUM TOWERS HOMEOWNERS
The Millennium Towers in San Francisco is built on landfill. It is the heaviest concrete building built in this seismic zone and, unlike other neighboring buildings, it is not anchored into the bedrock below. It has been reported that the building was expected to settle evenly to the depth of approximately 6 inches over its lifetime, but has now settled 12 ÛÒ 16 inches and is leaning 15 inches at its top to the northwest. We are informed that some owners are reporting problems with uneven floors, difficulty opening and closing doors, windows, and cabinets, and that some interior wall cracks have been observed. To date, none of the potentially responsible parties have accepted any responsibility for this problem nor have they offered any assurance that this condition will not continue to deteriorate."
Apparently they can't locate the Surveyor.
Here's the website.
Tommy Young, post: 384137, member: 703 wrote: What, he didn't charge for the hose?
It's not a "hose "... it's a flexible low volume hydraulic structure stabilization device .
The fact that the building didn't go to bedrock isn't the issue. All the buildings in that area only went to the highly consolidated sand layer. The building next door is a monopile. This issue is that this building is all concrete, while the other buildings are steel framed. This greatly contributed to the vertical loads, that while known, impacted the consolidated sand layer so much more. Dewatering a cohesiveless soil like sand can certainly increase the rate of settlement in this area with a shallow groundwater table.
imaudigger, post: 402032, member: 7286 wrote: I'm surprised that nobody else noticed that the story stated that satellite images have confirmed that the building had settled .13' in 12 months.
If we can determine elevations on earth within .13' from images captured in space....why the heck don't we have much better national elevation grids?
I'm thinking the press got it wrong again.
I think they are talking about relative changes, not absolute elevations, like NAVD88. Using sequential InSAR scenes from a common satellite to develop an interferogram, vertical change detection on the level of a few millimeters is attainable. This is one of the tools being used effectively to detect, measure, and monitor land subsidence in California and elsewhere.
SPMPLS, post: 402044, member: 11785 wrote: .... Using sequential InSAR scenes from a common satellite to develop an interferogram, vertical change detection on the level of a few millimeters is attainable....
Nice. But a $500 level and a $75 level rod would have detected that movement just as well.
SPMPLS, post: 402044, member: 11785 wrote: I think they are talking about relative changes, not absolute elevations, like NAVD88. Using sequential InSAR scenes from a common satellite to develop an interferogram, vertical change detection on the level of a few millimeters is attainable. This is one of the tools being used effectively to detect, measure, and monitor land subsidence in California and elsewhere.
I did not know this.
Mark Mayer, post: 402047, member: 424 wrote: Nice. But a $500 level and a $75 level rod would have detected that movement just as well.
Perhaps in this case, that is true, However, when trying to detect and quantify land surface elevation changes due to subsidence over thousands of square miles of the Central Valley of California (or elsewhere), a level and a rod isn't going to help you much. If they (whoever did this analysis) already had the InSAR data covering this building, it probably took very little time to develop the interferogram to quantify the vertical changes of the building.
