Wind Calc BS Frame [PDF]

Zitiervorschau

Wind load calculation Site wind speed The site wind speed Vs for any particular direction should be calculated from where Vs = Vb × Sa × Sd × Ss × Sp

(Ref: 2.2.2 / BS 6399-2)

To determines a site wind speed, still corresponding to the hourly mean wind speeds at a height of 10 m above ground in the standard exposure, from the basic wind speed by applying corrections for the

site altitude, wind direction and season. Wind speed for the building location

=

36.00 m/sec

Sb is the terrain and building factor

=

1.780

obtained from 2.2.3.3.

(Considered effective height 10m site in Country, < 2km closest distance to sea) Vb is the basic wind speed

= 36.000 /

Sa is an altitude factor (see 2.2.2.2);

= 1 + 0.001∆s

∆s is an site altitude

=

5

Sa =

1.005

Sd is a direction factor (see 2.2.2.3);

=

1.000

Ss is a seasonal factor (see 2.2.2.4);

=

1.000

Sp is a probability factor (see 2.2.2.5).

=

1.000

1.780 =

20.22

m

Vs = 1.0 x 1.0 x 1.0 Site wind speed 25.0 Vs =x 1.005x 20.33 m/sec

Effective wind speed & Dynamic pressure

The effective wind speed Ve be calculated from Ve = Vs × Sb (by assuming closest distance to sea is 2km, Site in town) The value of the dynamic pressure qs of the standard method is given by qs = 0.613Ve2

(Ref: 2.1.2 / BS 6399-2)

Building Height (m)

Basic wind speed Vs

Terrain and Effective wind Dynamic pressure Building factor speed (m/sec) (kN/m2) Sb Ve = Vs × Sb qs = 0.613 × Ve2