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Millennium Tower is tilting, sinking

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Re: Millennium Tower is tilting, sinking

#31

Post by Finnucane »

Animats wrote: post #19

From the article: "To cut costs, Millennium did not drill piles to bedrock." I'm amazed that a building of that height would be built on a slab with friction piles in the mudflat fill zone of the SF bay. How did they get a building permit for that? 16 inches of sinkage in 8 years is huge. Building sinkage isn't all that unusual, but not for skyscrapers. There was a time when skyscrapers were only built on competent r…

Most of our big coastal cities are like that. Boston is about twice as big as it was in colonial times; all of the Back Bay is landfill. A lot of Cambridge is landfill. And yes, most of the taller buildings cluster around the more solid bedrock areas closer to downtown.

But the engineering principles needed here aren't unknown--cities like Las Vegas and New Orleans have modern buildings that are much taller than were thought possible in earlier times. If the developers didn't do it right because it was expensive, then it is on them.

Re: Millennium Tower is tilting, sinking

#33

Post by shepting »

Animats wrote: post #19

From the article: "To cut costs, Millennium did not drill piles to bedrock." I'm amazed that a building of that height would be built on a slab with friction piles in the mudflat fill zone of the SF bay. How did they get a building permit for that? 16 inches of sinkage in 8 years is huge. Building sinkage isn't all that unusual, but not for skyscrapers. There was a time when skyscrapers were only built on competent r…

There's another building that was built on friction piles: http://www.aboutcivil.org/burj-khalifa-design-construction-s...

Re: Millennium Tower is tilting, sinking

#34

Post by marcusgarvey »

erdevs wrote: post #8
cheeze wrote: post #3

What is the risk? Does this make the building more dangerous because it's in an earthquake-prone area? Obviously this doesn't sound good, but the article mentions that there is no threat to safety of occupants. Is it merely aesthetic?

How much stock should one put in that declaration of safety? It is from an "independent" analysis... but who paid the analysts? Or, suppose absolute freedom from bias... how many times have expert opinions of safety been wrong in the face of mother nature. Picture Fukushima. The risks in a tilting building are many. From a market value standpoint, homeowner value has already been destroyed simply by perception. If re…

>Taxpayers may well be pulled into the fray and suffer as well in these situations.

How might this happen - do you mean via the Transbay Dev.?

Re: Millennium Tower is tilting, sinking

#36

Post by WalterBright »

danieltillett wrote: post #24
WalterBright wrote: post #18

Earlier quoted context omitted.

One of the geologists told me a simple way to judge the slide risk. Look at the tree trunks. If tree trunks are leaning, or are curved, that indicates the ground under them is shifting.

Or there is a lot of wind from a prevailing direction :) The other thing to look at is fence posts if they are old.

I've seen fields of trees that have been clearly bent by the wind, they look different than ones from shifting ground. For one thing, there tend to be more branches on the downwind side.

Re: Millennium Tower is tilting, sinking

#37

Post by was_boring »

Finnucane wrote: post #31
Animats wrote: post #19

From the article: "To cut costs, Millennium did not drill piles to bedrock." I'm amazed that a building of that height would be built on a slab with friction piles in the mudflat fill zone of the SF bay. How did they get a building permit for that? 16 inches of sinkage in 8 years is huge. Building sinkage isn't all that unusual, but not for skyscrapers. There was a time when skyscrapers were only built on competent r…

Most of our big coastal cities are like that. Boston is about twice as big as it was in colonial times; all of the Back Bay is landfill. A lot of Cambridge is landfill. And yes, most of the taller buildings cluster around the more solid bedrock areas closer to downtown. But the engineering principles needed here aren't unknown--cities like Las Vegas and New Orleans have modern buildings that are much taller than were…

To add on, Chicago and New Orleans are both built on swamps, and the outer edges of New York are filled in -- making land for cities isn't the issue with the tower.

Re: Millennium Tower is tilting, sinking

#38

Post by paulsutter »

Animats wrote: post #19

From the article: "To cut costs, Millennium did not drill piles to bedrock." I'm amazed that a building of that height would be built on a slab with friction piles in the mudflat fill zone of the SF bay. How did they get a building permit for that? 16 inches of sinkage in 8 years is huge. Building sinkage isn't all that unusual, but not for skyscrapers. There was a time when skyscrapers were only built on competent r…

Am I reading that map right? Looks like the Millenium Tower is not in the fill zone on the shipwreck map? Hard to tell the shipwreck map looks a bit notional.
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