Llano River Bridge Collapse in Texas
Llano River Bridge Collapse in Texas
2
JAE (Structural)
(OP)
Video of the collapse due to high river:
https://www.youtube.com/watch?v=EY45z_vXbSQ
Before:

After:

https://www.youtube.com/watch?v=EY45z_vXbSQ
Before:

After:

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RE: Llano River Bridge Collapse in Texas
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RE: Llano River Bridge Collapse in Texas
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RE: Llano River Bridge Collapse in Texas
Brad Waybright
It's all okay as long as it's okay.
RE: Llano River Bridge Collapse in Texas
Mike McCann, PE, SE (WA)
RE: Llano River Bridge Collapse in Texas
How about 10 feet? Where do you draw the line? Most likely, it was adequate for a 500 year flood event. Depending on the foundation conditions, that extra 5 feet could cost quite a bit.
It also may not be as simple as just raising the bridge portion. What made the Sunshine Skyway bridge collapse much worse is that the bridge profile grade was on a crest, so drivers could not see that a span had collapsed in time to avoid driving off into the river.
RE: Llano River Bridge Collapse in Texas
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
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RE: Llano River Bridge Collapse in Texas
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
How much is the lack of usage going to cost the local economy?
Mike McCann, PE, SE (WA)
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
That supposes that this latest hurricane was "an extremely unlikely" event. One issue that the likelihood statistic is only based on the last 200 years or so. Another is that it's well known that the requirements have invariably gotten watered down because of the gnashing of teeth at the cost to implement designs for the actual extreme requirements.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Llano River Bridge Collapse in Texas
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
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The secret of life is not finding someone to live with
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RE: Llano River Bridge Collapse in Texas
Not necessarily. I was attempting to shed some light, in general terms, on the decision-making process used to set the design criteria for civil infrastructure. I haven't seem anything thus far indicating how the level of flooding in this instance would be classified. Nor have I seen what level of flooding event the bridge was designed for. Without those two pieces of information, it's impossible to say whether this was a design failure, the result of inadequate design criteria, or an extremely unlikely event which was not reasonable to anticipate, nor spend hundreds of thousands or millions of dollars to mitigate a tiny risk.
In hindsight, it's easy to say they should have spent the money, since it will now cost millions more to replace it. However, spending an extra million or so, of a finite budget, to potentially save this bridge from an event it isn't likely to ever see within its useful life, would have meant other bridges didn't get safety upgrades that could save lives. Maintaining infrastructure on a limited budget requires tradeoffs and making hard decisions about how to allocate resources. It must be done prudently, weighing risk against cost, and placing a high premium on the safety of those using that infrastructure.
RE: Llano River Bridge Collapse in Texas
This type of storm, and the hurricanes, continue to get more frequent and more severe.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Llano River Bridge Collapse in Texas
Yeah, I heard the same fear-mongering from the IPCC, too. The problem is that the evidence doesn't actually support that assumption.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Llano River Bridge Collapse in Texas
Sorry to be a contrarian, and I do hope you get some rain, but an El Nino means less rain for Australia, and we need it. We like the La Nina condition better.
RE: Llano River Bridge Collapse in Texas
https://www.noaa.gov/media-release/noaa-updates-te...
RE: Llano River Bridge Collapse in Texas
https://water.weather.gov/ahps2/hydrograph.php?wfo...
RE: Llano River Bridge Collapse in Texas
That seems pretty straightforward. What is it we are missing?
RE: Llano River Bridge Collapse in Texas
That the bridge was underdesigned? No, not necessarily. The design would have been based on the information available at the time, and we haven't been presented with what the design criteria was.
That the changes are due to global warming? Assuming that global warming is a real, long term trend, and not a normal cyclic fluctuation (and assuming it's not a completely fabricated phenomenon), it's only wild speculation, with no scientific foundation, that rainfall in Texas would be affected.
Actually, the heavy rainfall that caused this flooding on the Llano River was the result of a Pacific hurricane named Sergio.
RE: Llano River Bridge Collapse in Texas
Brad Waybright
It's all okay as long as it's okay.
RE: Llano River Bridge Collapse in Texas
The fact that, as IRstuff pointed out, we only have 200 years worth of data to work with, and only about the last 100 years for which we have actual measurements. To set the criteria for what constitutes a 100-year (or even 25-year) event with any accuracy, you need far more 100 or even 200 years worth of data. Also, statistically speaking, 2 or even 3 "100-year events" can happen within a few years of each other; that doesn't suddenly make them 5-year events.
Anyway, my comment was primarily aimed at the assertion of hurricanes becoming more frequent and more severe, which is not supported by the facts.
RE: Llano River Bridge Collapse in Texas
It means that you were wrong when you claimed that the statement "This type of storm, and the hurricanes, continue to get more frequent and more severe" was fear-mongering and unsupported by evidence. There's the evidence for you. There is evidence that it's not just Texas. Do you want to read more studies?
Hurricane Sergio, by the way, was the record setting eighth Category 4 hurricane to form in the East Pacific this year. The old record of seven Category 4 having only been set in 2015. All just a strange coincidence I guess.
RE: Llano River Bridge Collapse in Texas
Have you ever cracked open a copy of Atlas 14? The statistical analysis is all there (with confidence intervals) in hundreds of pages of details. It's not like they are licking their finger and sticking it in the wind.
http://www.nws.noaa.gov/oh/hdsc/PF_documents/Atlas...
RE: Llano River Bridge Collapse in Texas
Regional rainfall patterns change. Regional rainfall patterns have changed throughout recorded history. There is historical evidence of changing regional rainfall patterns as far back as you care to go. It's not evidence of anything other than the Earth is constantly changing, as it has since it was created.
"All just a strange coincidence I guess."
Technically, it's a statistical anomoly, but you can buy into the junk science if you choose.
"Sez who?"
My college statistics teacher...and the book he taught from.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
What have I presented that's the junk science you claim I have bought into?
Though I'm not even really sure what your position is at this point, I'm curious; aside from anonymous professors and their unnamed textbooks, do you have anything to contribute from reputable sources (say something not founded by a political hack with no education in the field of climate science)? Substantial amounts of actual science is what I'm specifically looking for here. Climate Depot is a cesspool. Granted, there might be a grain of knowledge there... somewhere... maybe. But I've never been one to dive into a septic tank just because someone might have dropped a gold ring in it.
RE: Llano River Bridge Collapse in Texas
Brad Waybright
It's all okay as long as it's okay.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
That is not true. How the climate changes, how it is manifested in different areas and in different seasons, the weight of dozens of complex variables... is not well understood in the same way we understand heat transfer or harmonic resonance.
While our knowledge is constantly improving regarding climate, to say that the debate is settled is a political statement, not a scientific one.
Engineers tend to make similar statistical mistakes as non-engineers, in that they:
1) tend to assign higher confidence levels (and smaller error) based on a relatively small amount of currently available data, and
2) more weight is placed on more recent events and anecdotal evidence.
[By the way, weather in my area has been real nice in the last 15 years. That must count for something, right? No earthquakes either.]
Seems like humility is lacking when it comes to complex subjects like climate. In every other area of science and engineering it is good to question and re-examine our assumptions. This is true of climate science as well - from the left and the right. If you are screaming at your computer screen right now, you might not be able to think clearly.
Anyway, back to the original post. Thanks to JAE for making us all think about failure and overconfidence during design.
RE: Llano River Bridge Collapse in Texas
A "100-year event" is an event that has a 0.01 (or 1%) probability of occurring in a given year. It does not mean once in 100 years. The "year" value is simply the reciprocal of the probability (e.g., a 5-year event has a 0.20 or 20% probability of occurring in a given year).
The "year" nomenclature is ostensibly a simplification to better communicate the meaning to people who don't understand probability, but it has lead to a complete misunderstanding of the frequency of events.
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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill
RE: Llano River Bridge Collapse in Texas
https://en.wikipedia.org/wiki/Scientific_opinion_o...
I am aware of no real scientific debate regarding the following statements:
- "Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia".
- "Atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years".
- Human influence on the climate system is clear. It is extremely likely (95-100% probability)that human influence was the dominant cause of global warming between 1951-2010.
- "Increasing magnitudes of [global] warming increase the likelihood of severe, pervasive, and irreversible impacts"
- "A first step towards adaptation to future climate change is reducing vulnerability and exposure to present climate variability"
- "The overall risks of climate change impacts can be reduced by limiting the rate and magnitude of climate change"
- Without new policies to mitigate climate change, projections suggest an increase in global mean temperature in 2100 of 3.7 to 4.8 °C, relative to pre-industrial levels (median values; the range is 2.5 to 7.8 °C including climate uncertainty).
- The current trajectory of global greenhouse gas emissions is not consistent with limiting global warming to below 1.5 or 2 °C, relative to pre-industrial levels.[19] Pledges made as part of the Cancún Agreements are broadly consistent with cost-effective scenarios that give a "likely" chance (66-100% probability) of limiting global warming (in 2100) to below 3 °C, relative to pre-industrial levels.
No scientific body of national or international standing maintains a formal opinion dissenting from any of these main points. The last national or international scientific body to drop dissent was the American Association of Petroleum Geologists, which in 2007 updated its statement to its current non-committal position; and stated in 2010 that: "Climate change is peripheral at best to our science […] AAPG does not have credibility in that field […] and as a group we have no particular knowledge of global atmospheric geophysics." Some other organizations, primarily those focusing on geology, also hold non-committal positions.As scientific debate goes, it seems as if those points are "settled." Is there more research to be done? Sure! Will some of the estimates be subject to change? Certainly! But to suggest that there is still viable scientific debate happening regarding the points above is just not grounded in reality.
Considering there hasn't been any evidence to the contrary presented here, I'd be glad to getting back to discussing how these changes will affect our infrastructure and the need to properly assess the associated risks as well.
RE: Llano River Bridge Collapse in Texas
No matter how it's interpreted, it doesn't change the substance of my point. Two 1% probability events in close proximity do not indicate the statistical probability has changed.
Brad Waybright
It's all okay as long as it's okay.
RE: Llano River Bridge Collapse in Texas
B.E.
You are judged not by what you know, but by what you can do.
RE: Llano River Bridge Collapse in Texas
Any attempt to tie this flooding event to global warming is ridiculous political rhetoric, not worthy of level of discourse that should be expected in a professional forum. If you can't sort out the obvious distinctions between trends in the global climate and regional variations in weather patterns, I find little reason to debate the subject further.
fel3, berkshire, and theBard3, thank you for the explanations of probabilities as it relates to 100-year events, etc. As I was on the road today, I was thinking of a response along the same lines. If you flip a coin 8 times (representing the prediction a 25-year event with 200 years worth of data) and it comes up heads 6 times, that does not mean that the chance of getting heads is 75%. It's a statistical anomaly, primarily attributable to an insufficient sample size.
RE: Llano River Bridge Collapse in Texas
I wonder how much of our infrastructure will be washed away before people accept the truth. That is the real "failure and disaster".
RE: Llano River Bridge Collapse in Texas
We have recently built-up many areas more that in the past. So there are more structures and people for these storms to impact. This just makes the impact and devastation of the humans and infrastructure worse then what has occurred historically. But, that impact is often confused with it being a worse storm event.
East Pacific - I believe there have been 2 category 5 hurricanes this year. Apparently 1994 had 3 stronger ones. Just saying...
RE: Llano River Bridge Collapse in Texas
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Llano River Bridge Collapse in Texas
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
As for the articles cited, they're comparing apples to oranges, almost literally, since the hurricanes they're talking about are more apropos for latitudes where apples are common fruit, as opposed to tropical hurricanes, where oranges are more common.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Llano River Bridge Collapse in Texas
What I meant to say is the following.
Engineers tend to make similar statistical mistakes as non-engineers, in that they:
1) tend to assign higher confidence levels (and smaller error) based on a relatively small amount of currently available data, and
2) more weight is placed on more recent events and anecdotal evidence.
3) mix correlation with causation, or get causal arrows flipped.
For my friends who believe themselves to be experts in data analysis, here's a basic question that we should all get about the same answer:
How many data points do you need to predict a future event with 98% certainty that you are within 2% error, assuming no accurate priors?
Then ask yourself how might you aggregate and sort the data from various cities across the last, say 300 years? Clearly we can draw a few hundred different curves.
And lastly, ask yourself, why is it that the vast majority of individuals that assign extreme weather-related events as a direct result of climate change also have similar political views?
No doubt the climate is changing; can't quantity all the reasons, nor are predictions that I've seen very accurate. But we're just human, and even smart people have biases.
Engineer takeaway: reason is your companion, but the Code is your friend. Let the Code guys and gals define the extreme events.
RE: Llano River Bridge Collapse in Texas
And how are they different from the engineers that tend to make similar statistical mistakes as non-engineers?
The news had quite a bit about how South Florida's building codes got washed down from what they should have been.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: Llano River Bridge Collapse in Texas
I wonder if that's a statement born of a North American experience of the debate?
An observation worth bearing in mind while doing the "asking yourself" recommended in the first quote.
(Rats. I'd promised myself I wouldn't get embroiled in this spat).
A.
RE: Llano River Bridge Collapse in Texas
I quit after my original first post!
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RE: Llano River Bridge Collapse in Texas
It is what allows people to dismiss the actual honest to god science as "old, tired, debunked rhetoric" that's not provable. That's the same argument that one of my PE "mentors" made about evolution. "Prove it!" Haha, right? For some people, maybe not haha. Creationism is something which was revealed to them and they choose to believe rather than to accept the science. This mentor was a special kind of creationist who believed that the planet was only 6,000 years old. When faced with the reality that it was billions of years old, the response was the same. "Prove it!" Carbon dating? Flawed. The geologic record? Misinterpreted. The statistics that supported it all? Contrived. I kid you not... when mentioning plate tectonics in a discussion about an earthquake this person responded, "plate tectonics is just a theory." I guess the main thing he taught me was that you don't have to be smart to be an engineer.
What's the point of all of that? Acceptance vs. Belief. Discovery vs. Revelation. When I see that no scientific body of national or international standing maintains a formal opinion dissenting from of the main points regarding climate change that I posted above, I accept that science. Likewise evolution. Likewise the age of the planet. Likewise plate tectonics even. The science is what the science is. As such, I'm going to stay in my lane. Alternatively, in the case of climate change, I can accept what is revealed to me by Exxon Mobil and the petrochemical geologists and political hacks and everyone else who has a vested interest in the status quo that got us here.
It's remarkable that this discussion regarding precipitation intensity took the same tack as the climate change debate writ large. The first approach to dismissing the science was outright denial that the climate was changing ("The problem is that the evidence doesn't actually support that assumption."). When it became clear that it was indeed changing, then it transitioned to obfuscation; i.e. "So, perhaps the rainfall patterns in Texas are changing. It's always been changing. This is all completely normal." And it's interesting to me how the statement that set all of this off "This type of storm, and the hurricanes, continue to get more frequent and more severe." made no mention whatsoever to the climate change debate. It was injected by someone who wanted to argue against it and take the opportunity to make wholly unsupported claims that it was (to paraphrase) "debunked fear-mongering rhetoric."
RE: Llano River Bridge Collapse in Texas
I wasn't talking about the strength scale; I was referring to the lack of tools available to accurately measure the strength of the hurricanes that did occur during those earlier years.
"...since the hurricanes they're talking about are more apropos for latitudes where apples are common fruit, as opposed to tropical hurricanes, where oranges are more common."
When did I assert that my statement only applied to tropical hurricanes? For that matter, when did you?
RE: Llano River Bridge Collapse in Texas
Perhaps you should have looked more closely at the statement I was responding to, before making incorrect assumptions about it. My response was to the statement "This type of storm, and the hurricanes, continue to get more frequent and more severe." Over hundreds and thousands of years, regional and global climates experience change. There is much evidence that this does indeed occur, and I would not attempt to dispute that. However, the evidence does not support the contention that there is really a regional or global change in the number or severity of hurricanes or other storms.
BTW, using double quotes, which denotes a direct quote of someone, and then inserting your own (incorrect) interpretation of what the person said, is bad form, and a sure sign of desperation.
RE: Llano River Bridge Collapse in Texas
There is evidence of a regional change in the intensity of storms. I posted it. You acknowledged it (twice; "So, perhaps the rainfall patterns in Texas are changing." "Regional rainfall patterns change."). You seem like you might be disoriented by some cognitive dissonance you experiencing.
Even in your post above, you say there is evidence of change... then the very next sentence you say the evidence doesn't support that there is a change.
So out of one side of your mouth you're saying there is always change (dismissing/diminishing it), and the other you say there is no evidence of change (denying it). Which is it?
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
Someday Spartan5, perhaps you'll grasp the difference between accepting the obvious that change does happen, and accepting the unsupported assertion that a particular change is taking place in a particular region at a particular time. I'm rapidly losing hope, though.
Again, nice graphs, but completely irrelevant.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
I accept the science though. The science that has been supported by detailed and comprehensive statistical analysis conducted by experts in their field, and published for all to validate and comment on.
Are you really trying to tell all of us that what I posted is an unsupported assertion: In Austin, for example, 100-year rainfall amounts for 24 hours increased as much as three inches up to 13 inches. 100-year estimates around Houston increased from 13 inches to 18 inches and values previously classified as 100-year events are now much more frequent 25-year events. Do you really profess to know more about statistics than those who completed that work?
RE: Llano River Bridge Collapse in Texas
I didn't see a claim in that statement that the climate in Austin, Texas has changed, only that the statistical probabilities related to rainfall amounts have been revised based recent data. If 50 years from now, they haven't seen rainfall events as significant as those occurring recently, the probabilities will likely be revised back down. As I tried to explain to you several times, regardless of what the rainfall amounts average out to be, or how those averages get revised in the future, it is not necessarily evidence of a change in the climate. It could very well be due to the historical record being inadequate to accurately establish the probabilities. The sample size is just to small to really know.
RE: Llano River Bridge Collapse in Texas
I surrender.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
I pointed out that the same basic instrument for the measurement of air speed was invented in 15th century, and the Beaufort system used anemometers for windspeed measurements in 1850, so it's been nearly 170 years of reasonably accurate windspeed measurement.
"...since the hurricanes they're talking about are more apropos for latitudes where apples are common fruit, as opposed to tropical hurricanes, where oranges are more common."
When did I assert that my statement only applied to tropical hurricanes? For that matter, when did you?"
You referenced a slew of articles, which, I pointed out, are talking about mid-latitude storms, and not tropical storms.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
Are you really going try to argue that a few anemometers can measure the intensity and size of a hurricane as accurately as a satellite? BTW, does your graph include only the intensity of the hurricanes as they made landfall? I'll bet most or all of the few anemometers that were around in the 1800's were land based.
"You referenced a slew of articles, which, I pointed out, are talking about mid-latitude storms, and not tropical storms."
Ok, fine. Since when is the count of tropical hurricanes more valid in determining the overall trend than mid-latitude hurricanes?
RE: Llano River Bridge Collapse in Texas
Also known as 'cognitive dissonance'. Nobody wins the argument, they just become more sure of their view.
Brad Waybright
It's all okay as long as it's okay.
RE: Llano River Bridge Collapse in Texas
Now, it's practically become a cult religion. The members point to all the papers printed agreeing with them, because nobody dares to disagree anymore. They get shouted down and driven away, from what I've seen. Anyone who dares to even ask what happened to the disastrous climate events predicted in the past, that we're supposed to be suffering from now, gets the same treatment.
Personally, I feel we do need to clean up our act - but not because of whether or not the climate might change. Just because of general pollution levels, less crap in the air, water, and land, and less waste. It seems like the responsible and efficient thing to do in any case.
Perhaps instead of threatening people with hell, we should be working on improving society and education so that they will willingly work towards a better future?
RE: Llano River Bridge Collapse in Texas
Now let's see what the first point of the WMO statement says about that: "1. Though there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date, no firm conclusion can be made on this point."
RE: Llano River Bridge Collapse in Texas
It'd sure be a shame if we spent all this time and effort to try to reduce pollution and human waste for nothing. Maybe after another 100 years of data the "debate" will finally be settled. Based off the ongoing arguments against evolution it doesn't seem likely.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
1994 had three Cat 5 hurricanes in the E. Pacific. Maybe you've missed the last two Cat 5s in 2018 because they've both happened in the last couple of weeks. But we've now tied the 1994 and 2002 record for Cat 5s with three, and surpassed the 2015 Record of seven Cat 4 or greater by three (now at ten on the season). That makes 2018 to be the most intense (Accumulated Cyclone Energy) in nearly 50 years of reliable measurements (since 1971). Just saying...
1994:
2018:
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
The formula is for the % probability of at least 1 occurrence in a particular number of years is: 100(1-(1-1/x)^n)
where x is the annual return period of the event (e.g. "100"-year storm) and n is the number of years for which you are assessing it could occur.
RE: Llano River Bridge Collapse in Texas
Success rate = p = 0.01 (forgive the term; success just means that event happens)
n = number of trials = 30 (one per year)
Number of successes = 1 or more
Likelihood = 26% for 1 or more (agrees with USGS, which is nice)
Likelihood = 22% for exactly 1 event
Likelihood = 74% for exactly 0 events
100-year event as a standard isn't so high after all, considering the damage levels.
Statistically, you could have (10) "100-year event" storms in 10 years or zero in 100 years. When many events occur back to back in the same year or consequential years, consider that your physical model might be wrong. Or you're just unlikely, like when New Zealand had a long string of destructive earthquakes 2010 thru 2011. Even if you consider that as a single event, that's extremely rare in the modern era.
Back to the original post.
Extremely rare events sometimes occur. Sometimes multiple extremely rare events occur back to back. If spending 5% extra gets you 30% more robustness to the unknown, I don't need any more math to convince me that's a good bargain. Just need someone to scratch up that extra 5%.
If using the term climate changes gets me that extra 5%, then sign me up.
RE: Llano River Bridge Collapse in Texas
Spartan5 - Your second sentence twisted what I wrote into something different. It's pathetic that you feel the need to repeatedly do that kind of thing to prove you're right. It's a real big surprise that were waiting with crossed fingers that another cat5 hurricane would develop so you could jump all over my post.
RE: Llano River Bridge Collapse in Texas
Remote Hawaiian Island Wiped Off The Map
“This event is confronting us with what the future could look like,” one federal scientist said about the loss of East Island, caused by Hurricane Walaka.
https://www.huffingtonpost.com/entry/hawaii-east-i...
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
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It's finding someone you can't live without
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
Oooo, scary stuff...until you realize it happens all the time and it has been happening forever. That little "spit of white sand" is no different than the numerous others that have come and gone over the years. You should know better than to take anything the Huffington Post says at face value.
RE: Llano River Bridge Collapse in Texas
Brad Waybright
It's all okay as long as it's okay.
RE: Llano River Bridge Collapse in Texas
I'm currently working on a design for a large municipal utility facility in coastal Florida, for which an extensive study was performed by one of the largest engineering firms in the world to determine the expected sea level rise by the year 2075. Based on that study (48" expected sea level rise, much greater than the sea level rise that was hypothesized only a few years earlier for that nuclear plant I mentioned, which is located only 20 miles away!), the elevation of the mat foundation will be raised up at a significant cost to taxpayers.
Good thing climate change isn't real, cuz I was starting to really get concerned there for a minute! I'll call up the mayor of Miami and tell him not to worry, we can lower the building back down...
Real science, real phenomena, real engineering.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
Did they use term "expected"? I've seen "anticipated" used in those type of studies, which is much different. When designing infrastructure where failure would mean the loss of life may be catastrophic, it's normal to design for a range of possibilities that includes even unlikely scenarios. Just because a nuke plant design is adequate for 4 feet of sea level rise, only means it is a real possibility, not that it is certain, or even likely.
RE: Llano River Bridge Collapse in Texas
I think places like Austin and Houston will have to adapt not only to climate change effects, but like stookeyfpe was saying, they will also need to update their flood projections to realistically take into account the effects of urbanization. Hopefully we at least learn from these disasters/failures and don't just rebuild or continue to build the exact same way.
RE: Llano River Bridge Collapse in Texas
I believe making blanket statements about what should have been done in the design of this bridge, without any knowledge of the costs involved, is frankly rather arrogant. The people who have to make these decisions face the impossible task of keeping the system safe and functional without enough money to do either. If they could predict the future as well as all of us can predict the past, perhaps they would have chosen differently. Then again, no lives were lost when this bridge washed away, so even in hindsight perhaps it was better to spend the limited resources on protecting people's lives.
RE: Llano River Bridge Collapse in Texas
Of course I'm not criticizing the designers of this bridge in TX for designing it with the best available knowledge at the time. But if the design flood has perhaps changed since then due to the information about climate change that we have now, isn't it just prudent engineering to factor that in to the new design?
I realize this discussion is beyond the scope of the original post, but I do believe it's an important discussion for engineers to be having right now. I just wanted to offer my some of my personal experience and views.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
Let's be clear, the evidence supports that a significant rise in sea level is possible, and therefore it is prudent to design for that possibility. The fact that the City of Miami is preparing for a particular rise in sea level does not reflect a likelihood of that eventuality.
RE: Llano River Bridge Collapse in Texas
Brad Waybright
It's all okay as long as it's okay.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
Brad Waybright
It's all okay as long as it's okay.
RE: Llano River Bridge Collapse in Texas
RE: Llano River Bridge Collapse in Texas
At the core of most of these disasters is the cost element that was traded against what level of risk could be reasonably defended in the case of an actual disaster. This is why industries are often not allowed to regulate themselves; their financial incentives are invariably overly skewed in the opposite direction of safety and conservatism.
TTFN (ta ta for now)
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RE: Llano River Bridge Collapse in Texas
Maybe a small point as regards to the flooding of the Missouri river, but maybe the Army Corp should have looked a little farther ahead as to what happens to the nuclear station downstream if the reservoirs are too full and need to dump water like crazy to avoid overtopping.
RE: Llano River Bridge Collapse in Texas