Wind Load

In poetry, songs, and story we like to use wind as a metaphor. For instance, the hit movie, gone with the with. In engineering if you thought you can take wind as metaphor you will be in big trouble because wind is no small matter as a matter of fact.

The first important parameter about wind is the time interval over which wind speed is averaged. For averaging intervals less than 1 minute, wind speeds are classified as gusts. On the other hand, for averaging intervals of one minute or longer are called sustained wind speeds. So if you are doing designing for any structure on sea you can refer to API-RP2A

Vh/VH = (h/H)^1/n

Vh = wind velocity at height h
VH = wind velocity at reference height, typically 10m
1/n = 1/13- 1/7 depending on 2 factors: (i) distance from land
(ii) averaging time interval

Just for info: you will get 1/13 for gust or you get 1/8 for sustained winds in the open sea.
So you can load the figure in the wind profile and get the design wind speed, V. So with that basic information we can calculate the static wind force Fw. So if you have curious mind you might be wondering how come the wind is not constant but we take it as static, does not represent the reality. Well, if you have thought that way you are right on the bull's eye. You see only if your structure least horizontal dimension/height is > 5 we worry about the wind sensitive. So if that case happen, we need to take into consideration the dynamic effect of the wind and the cyclic wind loads due to vortex shedding .

So complicated huh? Luckily most of structure you will stumble in your life is not wind sensitive. So continue about the static force by the wind.

Fw = (1/2)rV^2CsA

r = wind density
V = wind velocity that you get from the wind profile
Cs = Shape coefficient Cs = 1.5 for beams
Cs = 0.5 for cyclindrical section
Cs = 1 total projected area of platform
A = Area (just intution telling me that)

So the guidance from the API is that we've got to consider 2 case of wind load:
one) mean 1 hr wind speed to combined with extreme waves and current
two) used extreme wind speed without waves.

If you managed to read all, congratulations. But make sure do you own reflections on it as our memory will trick us, huh, huh, already times. That they said time heal because you forget, haha.