Wind loading
Wind loading
(OP)
I am looking at a building 45m above the ground in Kampala,Uganda. Since Ugandan Standards are not yet developed, British standards are used for structural design here but applying BS 6399-2 and using Indian Ocean as the sea level with basic wind speed of 32m/s yields lateral pressures in the region of (9-10)kN/m2, which appear unreasonable!
However, when I use Lake Victoria (major water body nearest to Kampala)as my sea level, the lateral pressure values fall to (2-3)kN/m2 which I believe are reasonable. Does everyone out there think this is a valid assumption?
However, when I use Lake Victoria (major water body nearest to Kampala)as my sea level, the lateral pressure values fall to (2-3)kN/m2 which I believe are reasonable. Does everyone out there think this is a valid assumption?






RE: Wind loading
Also are you satisfied that using 6399-2 is appropriate for your location?
RE: Wind loading
RE: Wind loading
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Wind loading
If I assume mean sea level to be lake victoria which is at an altitude of 1133m, the altitude factor falls to 1.03 thus site wind speed of 33m/s.
The major issue here is altitude factor. Please see the attached map of East Africa showing location of Kampala relative to the Indian ocean and Lake Victoria and advice if L.Victoria can be a reasonable "mean sea level".
The challenge in this part of the world is that local standards have not been developed so we have to use either British Standards or Eurocode.
RE: Wind loading
RE: Wind loading
RE: Wind loading
I would also use the Australian Standards for structural design, for the same reason. I think you are best advised to use standards familiar to you, with adjustments to suit the locale based on engineering judgment.
RE: Wind loading
Find a country with similar topography and weather conditions and make an informed amendment based on your knowledge of the area.
With Britain being a small island; the higher you go above sea level, the more isolated you become. Using our standards for that altitude would be the equivalent here of building a house on top of Ben Nevis.
RE: Wind loading
Extract from the Foreword at the start of the code below
This Part of BS 6399 is only applicable to sites in the UK. The climate dependent
factors (for altitude, direction, season and probability) have been calibrated
specifically for the UK. While the general methodology and pressure coefficients
given in this standard may be used in other wind climates, it is essential to ensure
that the reference wind data are consistent with the assumptions in this
standard. The value of the site wind speed Vs should be obtained from the
relevant meteorological authority.
RE: Wind loading
32m/s which sounds like a working wind speed or 50yr wind speed should result in about 2kPa or (2kN/m^2) at the top of a 45m building and 1kPa (1kN/m^2) at the base of the building.
RE: Wind loading
All about Eurocodes:
www.DesignToEurocodes.com
RE: Wind loading
For example the design wind speed for our friend here is 32 m/s while he is 1160 meters above sea level, while where I live it is 35 m/s although most of our land is few meters above sea level.
Regards
RE: Wind loading