Wind Loading on Buildings 2

[Strucguy33]

Have a question, well a couple actually. Can someone please explain to me the minimum wind load for a building that's required for design of MWFRS. ASCE 7 states 10 psf applied on an area of a vertical projected plane. By using the analytical method for bldg's of all heights say I come up with 3 psf for windward wall 4 psf leeward wall 2 psf winward roof horizontal vector and 2 psf leeward roof horizontal vector (11 psf) all loads directed in same direction, do i multiply all of the loads with the areas they cover and if its more than 10 psf on projected area then i use those loads. Otherwise use 10 psf on projected area, and if I use 10 psf on projected area what minimum psf do i use for uplift load if I'm too design MWFRS for 10 psf on a projected vertical plane. Hope someone can explain this to me!

 

[ZeroExperience]

I don't have an answer. I just have a college memory regarding your problem.

Within the first 3 months of my college career, I remember my Professor giving us a "Find the reactions to this sky scrapper subjected to the following load" problem on an exam. I was incredibly confused when I attempted the problem, and I remain amazed that professor would give us such a problem even when the majority of us had no idea on where to start.

Stay motivated.

 

[DaveAtkins]

You are correct--you check the loads you calculate on ALL surfaces against 10 psf on a vertical projected plane.

I have always interpreted this to mean there is no uplift involved with this additional check. Uplift is generally more of a concern when you are checking components and cladding.

DaveAtkins

 

[Strucguy33]

Thanks alot DaveAtkins!
Your response was very helpful.

 

[a2mfk]

What the heck is your wind speed, 50mph??

 

[abusementpark]

Can someone please explain to me the minimum wind load for a building that's required for design of MWFRS. ASCE 7 states 10 psf applied on an area of a vertical projected plane.

Where in ASCE 7 is this given as a general requirement? I believe it is only a requirement if you are using method 1.

 

[SteveGregory]

Methods 1, 2 and 3 are described in section 6.4, 6.5 and 6.6. Section 6.1 General applies to all methods. See 6.1.4.1 for the 10 psf minimum.

 

[msquared48]

The 10 psf minimum only applies to zones A, B, C, and D of Figure 6-2, with all other zones being zero.

If there is uplift on the roof structure, you still have to consider it, but the uplift need not be combined with the 10 psf minimum load. Instead, the uplift should be combined with the tabularized loads that summed to less than the 10 psf minimum, if that makes sense.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com