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[akuc007]

Hi all,
As i am in calculation of Wind load for 20m tall building based on BS 6399-2 (due to project requirement). However the project (location Qatar) spec provided the basic wind speed @ 3 sec gust wind speed.

Since the code is using Mean hourly wind speed as basic wind speed, i have to change the V(3sec-gust = 50 m/s)) to V(hourly mean =32.55 m/s) with (dividing) terrain and building factor Sb (table-4 [sb = 1.536] [conversion method given in forward]).

However to calculate the effective wind speed (to arrive dynamic pressure) again i have to multiply with Sb factor make V effective Ve = 50.75m/s (decimal changes due to Sd,Sp,Sa, Ss factor).

Where am i missing the influence of height of building.

regards
Arunkumar.

[vikram.jeet]

Not seen BS 6399-2

Wind loads Code IS 875part 3 take terrain height factor for working out wind speed at its table 2 ,, (coeff k2).

For Tall buildings , Gust factor Method as given at cl 10.2 &10.3 are there in IS.
Our Codes are revised based on research here as well as Internationally.

I Think if u follow IS code steps / procedure , some revelation of ht may be revealed to you while following BS parallely.


I am really sorry not to help in this aspect.

[akuc007]

Thanks for your reply Mr. Vikram.

however i have to use the BS code as project requirement. lets wait for some light on this by somebody.

The structures in the project are <15m so no much effect will be in reality. however i wonder where i loss of height effect during conversion.