How do you calculate wind load?

Armed with pressure and drag data, you can find the wind load using the following formula: force = area x pressure x Cd. Using the example of a flat section of a structure, the area – or length x width – can be set to 1 square foot, resulting in a wind load of 1 x 25.6 x 2 = 51.2 psf for a 100-mph wind.

Is 875 wind load calculation?

Calculate Basic Wind Speed, V b, based on mapped values (Figure 1 in Section 5) or the table supplied in Appendix A of IS 875. Calculate Probability Factor (risk coefficient), k 1, from Table 1 in Section 5 of IS 875. Calculate the k 2 Factor (Table 2 in IS 875) based on structure height and terrain category.

How do you calculate wind uplift on a roof?

The uplift force on each outer post is (1/2 the span projection + the outer overhang) * (1/2 the span width + the side overhang) = (25% of the roof area) * the net uplift (all the uplift minus the self-weight or ‘dead load’).

How are tower wind loads calculated?

The generic formula for calculating wind load is F = A x P x Cd, where F is the wind load, A is the surface area of the antenna (usually given in square feet), P is the wind pressure (calculated from another formula) and Cd is the drag coefficient.

How is wind rating calculated?

To identify a Wind Classification for a proposed domestic site there are four variables you must first identify. They are Region (Figure 1.0), Terrain Category, Shielding Factor and Topographic Classification. The Wind Classification can then be determined using Table 2.0.

How do you calculate wind speed and wind pressure?

Wind pressure is given by the equation P = 0.00256 x V2, where V is the speed of the wind in miles per hour (mph). The unit for wind pressure is pounds per square foot (psf). For example, if the wind speed is 70 mph, the wind pressure is 0.00256 x 702 = 12.5 psf.

How do you calculate effective wind area?

Height * Height / 3 spaced closely together the effective wind area can be ’rounded out’ and may be taken as height X height / 3 (H*H/3) (height or length of the component multiply by one third of the height or length of the component).

How do you convert wind speed to pressure?

Can you have a negative wind speed?

Wind speed is the vector difference between the airspeed and the ground speed. On a perfectly still day the wind speed is zero and the airspeed is equal to the ground speed. This gives a negative wind speed. At lift off, the airspeed is still 100 mph, the wind speed is -20 mph and the ground speed will now be 120 mph.

How are wind speed and wind measured?

Wind speed is normally measured by a cup anemometer consisting of three or four cups, conical or hemispherical in shape, mounted symmetrically about a vertical spindle. The wind blowing into the cups causes the spindle to rotate. Calibration corrections are applied to the measured wind speed.

How do you determine wind classification?

Wind classification is determined by the wind speed at a structure, which in turn is influenced by the terrain the wind flows over as it approaches the structure.

Calculating Wind Load Using the Generic Formula Define the generic formula. The generic formula for wind load is F = A x P x Cd where F is the force or wind load, A is the projected area of the object, P is the wind pressure, and Cd is the drag coefficient.

What is the equation for force of wind?

Force, Wind and Pressure. Force, generally defined as a push or pull, can be calculated using the formula force equals mass times acceleration (F = ma). Wind also pushes and pulls, generally with greater force when moving faster.

How do you calculate wind speed pressure?

Calculate wind pressure. Wind pressure is given by the equation P = 0.00256 x V 2, where V is the speed of the wind in miles per hour (mph). The unit for wind pressure is pounds per square foot (psf). For example, if the wind speed is 70 mph, the wind pressure is 0.00256 x 70 2 = 12.5 psf.