When holddowns & braced wall panels are not enough....

Started by MikeT, April 30, 2008, 03:21:14 PM

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MikeT

Images of the damage wrought by the recent tornadoes in Virginia.  Note the path of destruction and that even upscale homes (with presumably better construction behind them) disintegrate under these force...  I realize one cannot say for sure that these had better/best construction practices behind them, but I wonder if it it even matters.




Redoverfarm

Mike Besides concrete walls and ceilings I don't believe they make a residential structure that would withstand a direct hit.  With that kind of devistation something will have to give. I guess it goes back to the old saying " You can't fight mother nature".


ScottA

If those houses are anything like the ones built around here they aren't built any better than small starter houses. I've seen million dollar homes built exactly the same as cheap tract homes. They are just bigger, the construction is the same. Regardless I doubt any wood house could take a direct hit from a twister.

MikeT

A replay of my email conversation with my structural engineer (Jerry) after sharing these pics with him:

Jerry: It's unreal how some houses are reduced to nothing and others nearby are O.K. Unfortunately, or probably fortunately your house would do better in an 9.0 earthquake than a tornado.

Mike: After a 9.0 earthquake, I will more than likely not be able to get to my  beach house, even if it is still standing.

Jerry: It will still be standing, but just down the hill a little and leaning.

Pick your poison.

mt

PEG688



It may be standing , sort of but it would be inhabitable , sure all this engineering may save the odd life or two , due to places not totally collapsing , but they won't be fixable IF we get a big quake.

At least thats my opinion. 

Wind is hard to build against , so many little things can go wrong / get broken , like a door or window breaking , once that happens the domino effect takes over, another window , another door , the attic access blows open air / wind rushes to the ridge vent / soffit venting , a sheet of roof sheathing blows off and well you see . Folly really to" build for/ against " 8.0 or greater quakes or tornadoes.   
When in doubt , build it stout with something you know about .


John Raabe

I don't think it is practical to build a house to withstand forces that are very very unlikely to occur during its lifetime. That's what insurance is for.

If you are in a hurricane or tornado area you should be building using the best practice techniques we have talked about here before - basically well nailed off plywood sheathing at the corners with metal straps and brackets to tie the foundation, floors, walls and roof together. That will take care of the normal big storms, earthquakes and the 50 and perhaps 100 year events.

For those direct hits and 500 year events, do what our grandparents did - build a bomb/storm shelter dug into the ground. You may never need to use it but it provides peace of mind and a good place to store a few survival rations for any big emergencies.
None of us are as smart as all of us.

glenn kangiser

"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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John Raabe

Yes, make it nice enough (like Glenn did) and you may want to live there. :D

I'll bet Glenn's underground palace is very well protected against high wind forces. It would take an awful lot of suction to lift the roof off on that place.

However, I wonder if the place would do as well in a big 500 year California earthquake. :-\

I expect most of us would do best to get out of the house if we can and into the middle of the yard or garden. Doing so would probably be about as easy as riding a bucking bronco!
None of us are as smart as all of us.

MountainDon

#8
I wonder what protection I'd need to volcano proof my cabin. The last time it blew it left a big hole a five miles north of us.   ;D ;D ;D   My mountain ridge is mostly pumice. No tornadoes, hurricanes or floods though.  :D



It is considered dormant, not extinct.

Just because something has been done and has not failed, doesn't mean it is good design.


glenn kangiser

According to Oehler, these do well in an earthquake and roll with the earth, just a Frank Lloyd Wright's successful pier system on the motel in Japan that remained standing after the giant quake while many other things were destroyed.

I have considered adding steel continuity straps based on bracing I have done on steel buildings.

...and hope you're not building on top one of those, Don.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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MountainDon

Quote from: glenn kangiser on May 02, 2008, 07:58:00 PM
...and hope you're not building on top one of those, Don.

Front row center I think...  ???   We have a great view of what could be the stage.

Boy, talk about needing a heavy duty, reliable trail/game camera.

Just because something has been done and has not failed, doesn't mean it is good design.

glenn kangiser

...and Kevlar underwear.

Mike Oehler did mention that he thought the worst damage in the underground complex type building would be possibly a popped board and a bit of spilled dirt.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.