ASCE 7-05 Wind Design Intent 1

[Atomic25]

What exactly is the intent of the code when it comes to wind design? If your building is designed in a 90mph 3-sec gust zone, should it have absolutely no wind damage if an 89mph wind comes along during a severe storm? Obviously, neglect any impacts from flying debris. Also, can anyone pinpoint exactly what the wind is at the site if damage occurs?

 

[Lion06]

It is my understanding that the intent is that the building remain completely elastic during a design wind event.

 

[Structures33]

A design that resists the calculated wind forces for a given wind-zone is meant to do just that -- resist the wind forces. The members and connections are supposed to take the bending and transfer the lateral loads into the lateral resisting system. The design and attachment of c&c should withstand the forces at corners and edge conditions. There are miscellaneous things like shingles that may not necessarily be attached to resist the wind (although a good architect would specify adequate attachment) but all of the structural components should be damage-free under the design wind condition.
If it was suspected that any part of the structure had failed under a wind condition less than the design case, the drawings may be analyzed to determine if the design should have been able to resist the forces. Then the building would be analyzed to see if it was constructed according to the drawings -- i.e. analysis would be done to see where fault lies - the original design or the construction.

 

[Atomic25]

Well, a portion of roofing membrane ripped off during a storm with 80mph straight line winds and confirmed tornadoes in the area, yet the owner claims that since the winds weren't documented above 90mph, the contractor should be held liable. The building is 2 years old.

 

[JStructsteel]

Atomic25,
Did the building collapse during the storm? Thats the argument. If there is a manufacturers guidline for installing roof membrane, and then it failed, maybe they could be held liable.
Thats my thoughts

 

[swearingen]

The winds weren't documented over 80mph? Did he have an anemometer right next to the eave? Or even 50' from the building? If he didn't, how did he know the wind wasn't 100mph? Just because it registered 80mph on an anemometer "in the area" does not mean local velocities can't be significantly higher. There is very little chance he can prove his case. He will lose that one in a U.S. court...





If you "heard" it on the internet, it's guilty until proven innocent. - DCS

 

[UcfSE]

The 3-second gust wind speed we use in design is not the same as the wind speed typically reported by meteorologists and weather stations. An 80 mph sustained wind might have gusts over 90 mph. You would have to do more investigating and probably some calculations so that you are comparing apples to apples.

 

[DonPhillips]

Perhaps the owner can file an insurance claim and let the insurance company subrogate it if the contractor truely is responsible.

Don Phillips

http://worthingtonengineering.com