Wind Speed to Wind Load

The wind load is the pressure exerted by the static streamline, which is 0.5 x the density of the air x the [velocity squared], multiplied by the area of the surface being loaded, multiplied by the drag coefficient, which is a function of building size, shape, and the angle of impingement of the incoming air. It is the drag coefficient that requires attention.

I case of a roof the front side is loaded with a + pressure and the back side is loaded with a - pressure. Many times the roof is destroyed by the suction on the back side.

It is similar to a "wing" effect.

hii all.. im having some difficulties in solving my h.w so can you guyz help me

it is said to determine the external wind pressure on the roof of the rigid gabled frame of a school building with L=12m and h=12m and v=45m/s the wind direction is normal to the ridge.

i acctually donno the formal for finding the wind pressure

As long as I remember, all those values should be referred in the appropriate standard for buildings. I am not a specialist, but have heard a lot about it. Maybe a civil engineer here can help indicating which one is the correct.

As bhrescobar said, the design forces are covered by mandatory codes, here in the USA it is ASCE 7

In addition to the above formulas, you should still get a copy of the ASCE 7-XX (I have access to ASCE 7-02), and do a little research since you will need to use the components and cladding design pressures instead of the main force resisting system design pressures. The pressures are very different and since you are designing the cladding and glazing for the building using the components and cladding design pressures are more appropriate. With all due respect, I believe the formula given above is used to find the design wind loads for open buildings and other structures. I have not looked at the referenced thread, and so I apologize if I am repeating what is found there. The components and cladding design wind pressure formulas based on enclosed buildings for a building < 60ft is p = q_h*[(GC_p) – (GC_pi)]

p = design wind pressure in psf or N/m²

q_h = velocity pressure evaluated at mean roof height h using exposure categories

(GC_p) = external pressure coefficients given in Figures 6-11 through 6-16

(GC_pi) = internal pressure coefficient given in Figure 6.5

For a building > 60 ft the formula is different and more detailed so you should refer to the code book to make sure you use the correct formula.

Finding the Figures without the code book is almost impossible, but can be done. These formulas are according to method 2 as defined in the code book. Method 1 is a bit easier because you simply use the code book charts in Figure 6.3 which use the area of exposure, the zone of exposure on the building, whether the zone of exposure is on the wall or roof, and the basic wind speed. Either way you should be able to correctly design your cladding and glazing for the building. I hope this helps.

Cheers

According to Russian SNIP 2.01.07-85*

w0=0.61*v^2, N/m^2

where

w0 - wind load

0.61 is half of density of air

v - velocity of wind, metr per second (is measured at hight equal 10m)

Abdel beat me to it again!!!!! *LOL*......I swear he must have the fastest typing fingers in the world!!!! Another GA for him!!!!

The section which Abdel refers to is Section 6 of ASCE 7 / ANSI A58.1. BTW, There are other quite similar Codes in use too throughout the world, but ASCE 7 is probably the best known and most used....

One huge factor regarding wind loading (and a basic building block for Design Wind Loading) is based on exactly where you (or your project) is located, because that determines what the anticipated design wind speeds will be based on probability/statistics and locale.....you will need to use the "Basic Wind Speed" maps found in ASCE 7.

Just adding my 2 Cents in for good measure...

Did we ever figure out where in the world the OP is located? They never tell us.

Once this is known, then those familiar with local codes for the area can chime in.

There is no point to citing ASCE codes for a project located outside the US.

Many of these posters assume we are all in India. This is not always the case.

Some of the basic design principals discussed are universal however.

Quick question for the OP'er. I think many of us missed this in our responses, but I feel it must be asked anyhow....

Have you already obtained the wind force and building shape/size/mass etc based on the results of actual scaled Wind Tunnel Testing of the proposed structure and surrounds?

If so, than the determination of design wind forces for the design and analysis of building claddings is in another whole different league upon itself and I'm afraid ASCE 7/ANSI A58.1 may not be any significant help for you.

Though I ought to ask the $64,000 Question in case no one else thought to do so.....

Please have a great sunny day!!!