How do you compute the wind load in the area?Is it by zoning or every area has same or uniform wind velocity?

It depends on the type of structure and the dsesign code you follow. It is not still clear which area are you talking about. Is it on a high rise structure or steel framed structure such as industrial shed.

I usually calculate it on industrial shed as uniform speed as given by the code(I use IS code) and the calculation based on it is really simple and gives the accuracy and safety needed for this. You may also incorporate the dynamic effects if you like! This may give you an idea.

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it  depends at many factors according every  code and there are many  common factors as (degree of exposure for surface and building zone and type of surface exposured have oppening or not)

Considered factors in Wind load calculation:

1. Location of Structure

2. Type of Structure (Open, Enclosed, Partially Enclosed)

3. Height of Structure

4. Geometry of Structure

5. Purpose of the Structure

As mentioned by some of the friends it depends on the type of structure. Normally for high rise building Wind Tunnel tests are done. For any elelement of Building like Canopy we can compute from the Codes.

For free standing Structure like signborad code specifies the method to for Calculating Wind Load.

every area has a uniform wind velocity from it you can apply zicas equation to compute the wind load over the structure you wont also this equation depend on the hight of your structure.

there will be to type of calculation for wind, one according to UBC standard, and the other according to ASCE manual. and i think according to IBC we have to follow ASCE.