EN 1991-1-4 · SP RK EN

Wind friction force on building surfaces

Checks whether friction must be considered (5.3(4)); area A_fr beyond min(2b; 4h) from the upwind edge, c_fr from Table 7.10 and F_fr = c_fr·q_p(z_e)·A_fr.

Results

Detailed report

Project Subject Designer Date

About this calculation

Checks whether friction must be considered (5.3(4)); area A_fr beyond min(2b; 4h) from the upwind edge, c_fr from Table 7.10 and F_fr = c_fr·q_p(z_e)·A_fr.

Design basis

EN 1991-1-4, 5.3(3), 5.3(4), 7.5, Table 7.10

Input data

Wind at the site: Site; Kazakhstan wind zone; Fundamental basic wind velocity vb,0; Directional factor cdir; Season factor cseason; Terrain category (Table 4.1); Orography factor c0; Air density ρ
Building: L — building length (along the ridge, x axis); W — building width (y axis); h — building height (to the top); Roof (in the scheme); Roof pitch α; Wind direction θ
Surfaces (Table 7.10): Walls; Roof

Output

External pressure coefficients c_pe and pressures by zone
Peak velocity pressure q_p(z) with intermediate values
Zone layout and a detailed PDF, Word, Excel report

FAQ

Where do I get the basic wind velocity for Kazakhstan?

Start typing a settlement name — the wind zone and v_b,0 are filled from the SP RK EN 1991-1-4 map. The zone map is also available as a separate page.

Is internal pressure included?

Yes, c_pi per 7.2.9; internal pressure is given as a separate load and is not added to the external pressure.

Can the report be used in a design?

The report shows formulas, substitutions and clause references. Check national parameters against the current National Annex; the designer is responsible for the result.