• Wind actions on signboards according to Eurocode 1 part 4.

    In this design example we will try to present how to calculate the wind loads subjected to signboards according to Eurocode 1 (EN 1991-1-4). The dimensions of the signboard are h=7,00m and b=5,00m. It is separated from the ground by a height zg=1,50m. Finally, the value of the basic wind velocity is Vb=33m/s and the category of the terrain I (flat horizontal area with negligible vegetation and without obstacles).
    z0=0,01m and zmin=1,00m (EN 1991-1-4 Table 4.1)

    Reference Height - ze

    ze=zg+h/2=1,50+7,00/2=5,00m (EN 1991-1-4 Figure 7.21)

    Force Coefficients - cf

    zg=1,50m < h/4=7,00/4=1,75m

    b/h=5,00/7,00=0,714m < 1,00

    cf=1,80 (EN 1991-1-4 Clause 7.4.3 (2))

    Roughness factor - cr(z)

    z=ze=5,00m > zmin=1,00m

    cr(ze)=kr*ln(z/z0) (EN 1991-1-4 Expression 4.4)

    Terrain factor - kr

    kr=0,19*(z0/z0,II)^0,07=0,19*(0,01/0,05)^0,07=0,1698 (EN 1991-1-4 Expression 4.5)

    cr(ze)=kr*ln(z/z0)=0,1698*ln(5,00/0,01)=1,055 (EN 1991-1-4 Expression 4.4)

    Turbulence Intensity - Iv(z)

    z=ze=5,00m > zmin=1,00m

    Orography Factor: co(z)=1,00

    Iv(z)=kI/(co(z)*ln(z/z0))=1,00/(1,00*ln(5,00/0,01))=0,1609 (EN 1991-1-4 Expression 4.7)

    Basic Velocity Pressure - qb

    qb=0,50*ρ*Vb2=0,50*0,00125*332=0,68kN/m2 (EN 1991-1-4 Expression 4.10)

    Mean Wind Velocity - Vm

    Vm(z)=cr(z)*co(z)*Vb=1,055*1,00*33=34,82m/s (EN 1991-1-4 Expression 4.3)

    Peak Velocity Pressure - qp(z)

    qp(z)=(1+7*Iv(z))*0,50*ρ*Vm(z)2=(1+7*0,1609)*0,50*0,00125*34,822=1,61kN/m2 (EN 1991-1-4 Expression 4.8)

    Wind Force - Fw

    Fw=cf*qp(z)*Aref=1,80*1,61*(5*7)=101,43kN (EN 1991-1-4 Expression 5.3)

    Horizontal Eccentricity - e

    e=0,25*b=0,25*5=1,25m (EN 1991-1-4 Clause 7.4.3 (3))

    Please like us on facebook or follow us on twitter to stay informed of all the latest news and articles.
    -
Powered by vBulletin® Version 4.2.0
Copyright © 2014 vBulletin Solutions, Inc. All rights reserved.
DesignToEurocodes.com
All times are GMT +1. The time now is 09:23.
vBulletin 4.0 skin by CompleteVB