Stay out of Rowlett

[Mike]

you sure have a leisurely amount time to get into a bunker while the tornado sirens are going off.

I've never gone in a shelter simply because sirens were going off.

We usually know there is a chance for a tornado a couple of days before the "event", so obviously we take some necessary precautions leading up to it. There was around 40 minutes of lead time for Moore in 2013.

[Ruffdaddy]

you sure have a leisurely amount time to get into a bunker while the tornado sirens are going off.



*cough*

Most houses are built as a rigid structure with the loading coming from the top down (snow load), and not the side loading caused by tornado/hurricane force high winds. So as research has proven, just a minimal amount of lift on the roof will cause the whole structure fail with that side loading. Which is why some of the latest building standards include more specific anchoring methods, and more importantly strapping requirements to keep the roof secured to the walls, an the walls secured to the foundation

Learn to read.

Im not saying the roof doesnt produce lift. Im saying opening the garage will not increase that lift as a result of a Bernoulli effect. Claiming that it does means you dont understand basic aerodynamics.

[Tremor14]

but but, he used big words!

[John -- '02 HAWK]

Why would you leave the garage door open?

you sure have a leisurely amount time to get into a bunker while the tornado sirens are going off.

The roof will exhibit the same if not greater lift when all of the doors and windows are closed. As a matter of fact, opening everything may even produce negative lift similar to ground effect.

*cough*

Most houses are built as a rigid structure with the loading coming from the top down (snow load), and not the side loading caused by tornado/hurricane force high winds. So as research has proven, just a minimal amount of lift on the roof will cause the whole structure fail with that side loading. Which is why some of the latest building standards include more specific anchoring methods, and more importantly strapping requirements to keep the roof secured to the walls, an the walls secured to the foundation

[Tremor14]

/thread

[Ruffdaddy]

cannot confirm the validity of this statement until Jewwrick and Ruffdiddy get here.

Done. Now get to learning.

[Ruffdaddy]

Another way to think of it is this like an air dam on a race car. They produce downforce by allowing air to pass under them at a higher velocity. However, if its too close to the ground it stalls and just creates more drag while downforce figures drop off.

This goes for venturi tunnels on a ground effect car as well.

[Ruffdaddy]

The concern of mine is two fold

Concern one, is having to move a car to get into the shelter when seconds count.

Concern two, is when the garage door (or window/door) is opened it changes the dynamics of the wind's pressure am loading from going up and over the house to going through the house and over the house. This creates a Bernoulli effect (think wind over an airplane wing) and helps to lift and dislodge the house, as well changing the pressure loads on the house.

Lol...i think the bernoulli effect is the absolute last thing id be concerned with in this instance. The roof will exhibit the same if not greater lift when all of the doors and windows are closed. As a matter of fact, opening everything may even produce negative lift similar to ground effect.

But a simple bernoulli equation with unidirectional inviscid flow doesn't come close to explaining the turbulent 3 dimensional flow of a tornado.

While it would be fun to model this and run some CFD, thatll take forever to get results that are meaningless.

[BMCSean]

Why would you leave the garage door open?

Why not?

[Jewrrick]

cannot confirm the validity of this statement until Jewwrick and Ruffdiddy get here.

psh I know jack shit about aerodynamics

[Tremor14]

The concern of mine is two fold

Concern one, is having to move a car to get into the shelter when seconds count.

Concern two, is when the garage door (or window/door) is opened it changes the dynamics of the wind's pressure am loading from going up and over the house to going through the house and over the house. This creates a Bernoulli effect (think wind over an airplane wing) and helps to lift and dislodge the house, as well changing the pressure loads on the house.

cannot confirm the validity of this statement until Jewwrick and Ruffdiddy get here.

[Mike]

The concern of mine is two fold

Concern one, is having to move a car to get into the shelter when seconds count.

Concern two, is when the garage door (or window/door) is opened it changes the dynamics of the wind's pressure am loading from going up and over the house to going through the house and over the house. This creates a Bernoulli effect (think wind over an airplane wing) and helps to lift and dislodge the house, as well changing the pressure loads on the house.

Why would you leave the garage door open?

[John -- '02 HAWK]

Yeah, I don't think putting them under the garage is smart either. If house gets hit, you could be trapped there for days.

The concern of mine is two fold

Concern one, is having to move a car to get into the shelter when seconds count.

Concern two, is when the garage door (or window/door) is opened it changes the dynamics of the wind's pressure am loading from going up and over the house to going through the house and over the house. This creates a Bernoulli effect (think wind over an airplane wing) and helps to lift and dislodge the house, as well changing the pressure loads on the house.

[mstng86]

this is what i've been looking at for the next house. Above ground, concrete, vault sealed, and the room wired for TV/internet, etc. Make it my office/workroom

In that type of application, if its an add on to a house, is there any consideration to how heavy the added room is? The reason I ask is my stepdad added a room like that to their house and I believe it really jacked up the foundation due to the weight. the roof started having issues and that whole side of the house seem to be pulling away towards the new room he built on.

[Silverback]

this is what i've been looking at for the next house. Above ground, concrete, vault sealed, and the room wired for TV/internet, etc. Make it my office/workroom