i’m with you with using spring linking. But i want to see them swaying in sync. At least we germans have a reputation of beeing Schunkeln fans,
Dear Millennium Tower resident,
By now you have heard of the recent troubles. Know that all necessary safety steps are being taken and there is absolutely no danger. When, however, you hear the building klaxon sound, please proceed IMMEDIATELY to the furthest SOUTHEAST corner of your unit (i.e. upward) carrying whatever heavy objects you can gather. Thank you for your cooperation in this matter.
1/4" of lean at the top of a high-rise could be the difference of a totally calm day vs someone a few blocks playing the big bad wolf and huffing and puffing. I’m surprised they even announced an additional 1/4" lean, I wonder what the survey crew’s or the instruments margin of confidence is on that measurement.
A sustained quarter inch over four days is not caused by the wind. Especially when added to the existing lean.
A quarter of an inch every few days starts to add up real quick.
That’s not at all what ag53 was suggesting. A typical skyscraper is constantly swaying in the wind by several inches and depending on predominant winds on a given day the average position of the top of the building on any given day can vary somewhat. So how confident are the engineers that the building has actually shifted 1/4" vs the normal daily variance?
You should call and let them know they have been measuring wrong and should stop the work.
Except we’re not talking about a temporary wobble, we’re talking about a sustained lean that is continually getting worse. All those little movements keep adding up.
Why would I do that? The complaint is that nobody is providing confidence intervals or anything useful for understanding how meaningful or precise that reading is and it’s extremely difficult to get a precise measurement of the unloaded state while it’s constantly swaying under variable load. To make matters worse is that all of the loudest people are the most biased, either saying that this is a huge deal or it means nothing and the people who actually have more information while not being as biased aren’t the ones the media is talking to. edit: when I’ve gone looking for the settlement tilt of the tower, the estimated precision of most the older measurements was on the order of 1-3 cm (largely because the building is constantly moving). So in the past none of the measurements would be precise enough to be confident that a 1/4 inch difference was in any way meaningful. Presumably there are more precise measurements now but exactly how precise are they?
ah, yes, the expenditure of money in order to preserve the property value of luxury condos, and all the surrounding legal minutia and consequences. to say nothing of the sheer technical challenge of engineering this!
Seems like there should be something approaching an exponential here. Not in a good way.
Are they not just using the means of multiple measurements taken over the course of each day in order to plot a trend? I very much doubt that they are relying on any one measurement to determine the extent or speed to which the building is leaning at any point in time.
Can someone point me to an in-depth analysis what would happen financially if this particular tower were to collapse? What buildings are in the pathway and how many blocks would need to be closed? What underground transit stations would be affected? I’m sure these contingency plans have already been written by someone in disaster planning, but they might be confidential until it occurs. A comparison to the World Trade Center is probably the closest thing we could relate it to.
So tell me what happens if the predominant wind is blowing from the north on one day and from the east on the next? How much will the measurement differ? Then there’s also temperature differences and the differences between sunny days and cloudy days. Steel, over the height of the tower expands by about an inch with just 20 degrees F difference. On a sunny day you’re going to have more expansion on one side than the other vs a cloudy day where it will be relatively equal expansion on both sides. How much is that difference in terms of the measured tilt of the tower? Presumably much of this is mapped out at some level but the point is that aggregate readings over just a day or even 5 can potentially still have a significant bias to them. How much is that bias? And if you can’t tell me specifically how much that bias is then why are you so certain that 1/4" is significant and not noise?
Buckminster Fuller to a lecture hall, recounted in the voice and cadence of Laurie Anderson: “Do you ever think about how much your buildings… actually… weigh.”
Who said they’re measuring at the top of the building? They can measure tilt just as well by measuring points around the base of the building, and extrapolating to the displacement at the top.
Also, it’s entirely possible to record the exact position of the top of the building, graph that, and take the prevailing wind into account when calculating the average position.
Or, better, do both and compare the results. If two such disparate methods come up with roughly the same answer, you’re probably on to something.
I’m not saying that’s how they’re doing it, but it’s not an impossible problem. And I’m not even a civil engineer.
Are you suggesting that it is impossible to measure the lean of a building in increments of 1/4" due to the dependency on other variables or are you suggesting that it is possible, but you do not trust that they are doing it correctly because you have not seen the raw data with your own eyes?
I wondered that as well. Describing lean in inches seems wrong. Wouldn’t it be better to use degrees off plumb? My (likely wrong) math says a lean of 2’ in 645’ height is about 0.17 degrees.
Is Pep Boys’ cyber week deal on car jacks still going?
That’s only like 23 inches/year. No worries.
I was thinking bowling ball for testing. Or marbles. Whatever.