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Hurricane Simulator to Destroy Full Size Building
Anonymous Coward writes "This is a shameless plug, but I thought Slashdot readers might be interested in the hurricane simulator system the company I work for (Cambridge Consultants) helped develop for the University of Western Ontario. The BBC article is light on the kind of technical details Slashdot readers enjoy, so here are some titbits. The servomotors for the 100+ valves are controlled over an IPv4, gigabit Ethernet network connected to an Athlon dual-core AMD64 PC. The entire real-time control system runs on this machine, utilizing well above 90% of each processor core, and roughly 30% of the network capacity. The sampling frequency of the control system places a huge demand on the machine, with about 70,000 context switches taking place every second. Yes, it runs Linux. "
Does it run on Lin...
Dammit, you stole my line!
does it run Vista?
If you guys in Western Ontario want a hurricane so bad why don't you just come live here in Key West, Florida?
WARNING: Smartphones have side effects--most of them undocumented.
10% idle
89.95% kernel (switching threads)
0.05% user (generating 70,000 "blow" commands per second)
Hurricanes may blow, but abusing thread-level concurrancy definitely sucks.
...as if millions of nerds suddenly cried out, "yeah, but does it run...", and were suddenly silenced.
Yes, flying debris can punch holes in houses and such, but WIND is what will completely tear the house down (remember seing roofs blown off on your t.v. and whole houses collapsing?). The point is, they're NOT going to be able to do a goddamn thing about flying debris (well, they could build all houses out of 10" of tempered steel), what they are trying to do is make houses designed to be as hurricane resistant as possible.
FTA:"This is relevant because most of the damage to houses occurs in places where there are sudden changes in pressure, such as at the corners and edges of the building.
"You get swirling and rapid changes from positive to negative pressure," said Mr Wilkinson.
"If you were going to pull a panel off a roof you wouldn't just heave on it, you'd try to waggle it, and that's the most destructive thing for the wind to do.""
A computer once beat me at chess, but it was no match for me at kick boxing.
Yeah, I'm pretty sure the guys doing the experiments didn't think of that, good thing you happened to be here to set them straight.
Hurricane simulation in Canada, The Carolina Hurricanes in North Carolina winning the Stanley Cup, the world is coming to an end.
If you want to know what a hurricane does, study the effects of hurricanes. One of the best studies was done after Hurricane Andrew and the results were published in Fine Homebuilding Magazine.
What they found that the building code was pretty good. There were a couple of issues.
The rain of an actual hurricane was responsible for a lot of the destroyed homes. Rain would get up under the shingles and soak the fiberboard sheathing. The sheathing would swell and the roofing staples would then cut into the sheathing and the sheathing would blow off. Once that happened, the house was toast.
Another issue was that builders didn't always build to code. They found a lot of nails that missed the lumber they were aimed at.
This experiment misses a couple of things that caused most of the destruction during Hurricane Andrew.
If you state what winds you want a house to withstand, you can reliably build the house to withstand those winds. I am skeptical that this experiment will turn up anything we didn't already know.
They're forgetting the most destructive part of a hurricane. Granted strong winds can and will do a significant amount of damage (I still remember what my parents house looked like after Ivan), but the most damage is done along the coastline where they get hit by storm surge. That's not something that can be replicated by a wind tunnel on a full scale. I drove along the southern Mississippi coast about 3 weeks ago. There is wind damage for miles inland, which I would expect, but it's nothing major. However the coastline is devastated. The first floors of buildings are completely washed out, destroying most of the buildings completely. The ones that were multi-story are collapsing in on themselves because their support is gone. Testing building construction in a simulator is a good place to start, but I hope it doesn't give people a false sense of security.
I figured I'd chime in here as a Western Engineering Student, who had Prof. Kopp last year, let you know what he was up to in the Fall. Kopp only taught the second half of my course because the first half of the year (during Hurricane season) he went to New Orleans to study the devistation.
This project isn't meant to make a perfectly hurricane resistant house (though, you could try based on the results). As far as I know, the aim is to find what little things can be done to the average house to improve the chances of survival for the house, or at least the people in it. In the example of nailing trusses to the walls of the house, anyone who's actually been there to see or nailed a truss can attest to how weak that connection can be, and one possible change is to mandate exactly how the trusses need to be nailed, and perhaps develop a new nailing plate to ensure that the placement of the nail is exact each time (if there is a steel plate on each truss with only one hole, you know where the nail is going).
Also, for anyone wondering "why Western Ontario?", UWO is home to a very well respected wintunnel lab, which has tested many very well known buildings (Athens Olympic Stadium, CN Tower, numerous tall buildings in China to name a few). You can take a look here: http://www.blwtl.uwo.ca/Public/Home.aspx
You don't need to run simulations yet. There are still plenty of real world data to collect before you can adequately simulate any hurricane. There are tens of thousands of buildings of every type here on the Gulf coast that can be assessed right now. Damage runs the full gamut, from light to catastrophic.
I live in a FEMA trailer. The western eyewall of Hurricane Katrina passed over my house. Various official guesstimates of wind velocity at the time were high Category 3 to low Category 4 - roughly 130mph or 210 kph. In my neighborhood, houses suffered everything from light roof damage from wind and felled trees, to complete destruction; nothing left but a pile of 2x4's. A few houses were swept away entirely, along with cars, boats and anything else that was not tied down.
My house is an ordinary 25 year old, rectangular, brick clad, single storey building with a simple hip roof and traditional construction. There are no hurricane straps anywhere in the house. The house structure survived just fine. Not a single window was broken, though most had water infiltrate between the panes. Roof damage was minor, it never sprung a leak, but it has been re-shingled since the storm. What put me into a trailer was the storm surge of 15 feet, over four feet of water in the house for several hours. The interior is still entirely gutted.
Between damage to the wiring, flooring, drywall, insulation, kitchen and bathroom cabinets, appliances, HVAC unit, furniture and all the rest of the contents of the house and garage, I'd just as soon build a brand new house from scratch. There would be a lot fewer headaches, and not much more expense.
So what's my point? It's simple. If you'll spend a few month in this area, you'll learn more about hurricane hazards than decades of laboratory simulations. There are too many parameters to get right before simulation results will yield much knowledge.
IANAE, but from my observation of damage from New Orleans to the Mississippi Gulf Coast there are several points to be made.
1) Straight line winds are just one hazard. The level of damage varies with wind direction, velocity and duration, amount of rainfall, height and velocity of storm surge, duration of inundation, distance from open water, barriers both natural and man-made, proximity and height of neighboring structures, and tornadoes (there were lots of those embedded in the storm). And maybe other factors too, including luck.
2) No doubt, building codes play a role in preventing or mitigating wind damage.
3) Those fancy, intricate gabled roofs that are so popular on all the new McMansions? They suck. I don't care how many metal brackets hold them together. They're mincemeat in a real storm.
4) You can't do much against flood. High Base Food elevation is the only thing that will prevent flooding. Build high to remain dry.
5) Most of the stuff you own is located below a line four feet above the floor. The cost of a house's structure is relatively small compared to its contents, equipment, and interior finish.
6) If you're in the storm's bull's eye, like Pearlington, Waveland and Bay St. Louis MS were, there's not much to be gained by expensive reinforcement of an ordinary house structure. You just can't fully protect against the massive energy that a Katrina-sized storm carries onshore.
7) Don't trust the U.S. Army Corps of Engineers to protect you against anything.
8) Don't trust your insurance company.
9) When a hurricane's bearing down on you, don't worry about the house, get the hell out of town.