Xponexus Engineering

Wind action tools crafted for modern design teams.

Basic wind velocity v_b,0

Reference height z m

Directional factor c_dir –

Season factor c_season –

Orography factor c₀(z) –

Air density ρ kg/m³

Terrain category (Table 4.1)

0Sea / coastal

IOpen, flat

IILow vegetation

IIISuburban / forest

IVDense urban

Uses EN 1991-1-4 style expressions: v_b = c_dir · c_season · v_b,0, v_m(z) = c_r(z) · c₀(z) · v_b, q_p(z) = [1 + 7 I_v(z)] · ½ ρ v_m². Terrain parameters (z₀, z_min, k_r) follow the usual Eurocode terrain categories 0–IV.

Results

Design wind intensity based on input parameters.

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Peak velocity pressure

                  –
                  kN/m²
                
                  At reference height z
                
                  – m
                
              qp(z) is calculated with turbulence intensity Iv(z) and
              terrain-dependent roughness factor cr(z).
              Terrain II

Basic wind velocity

–m/s

Mean wind speed v_m(z)

–m/s

Roughness factor c_r(z)

––

Turbulence I_v(z)

––

The values above are for global wind action (peak velocity pressure). To obtain facade or roof pressures, multiply q_p(z) by suitable external and internal pressure coefficients (c_pe, c_pi) according to EN 1991-1-4 and the relevant National Annex.

Parameter	Symbol	Value	Unit
Basic wind velocity (site)	v_b	–	m/s
Fundamental basic velocity	v_b,0	–	m/s
Directional factor	c_dir	–	–
Season factor	c_season	–	–
Terrain category roughness length	z₀	–	m
Minimum height for category	z_min	–	m
Terrain factor	k_r	–	–
Reference height used	z	–	m
Peak velocity pressure	q_p(z)	–	Pa

Xponexus Engineering

Wind Design Intensity

Results