A= the plan projection of the surface area of roof supported by the member under analysis, in squaremetres.A= 50 x 35 = 1750So UDL = 0.25kPa Columns are spaced at 5m apart so the live load acting on the structure will be;0.25kN/m2x 5m =1.25kN/mA concentrated live load of 1.4kN must also be designed for2.Dead LoadSelf weight of roof or wall cladding, insulation, purlins/girts, frame and in-ceiling services can be taken as 0.25kPa. Dead Load = 0.25kN/m2x 5m= 1.25 kN/m3.Wind LoadWind pressure: P=0.5(ρair)[Vdesθ]2CfigCdyn
Design wind speedThe design wind speed was calculated in accordance with AS 1170.2Vdesθ=Vsitβ=VrMd(Mz ,catMsMt)V1000=60 m/sV20=38 m/sMd(overturning) = 0.95Md(other) = 1Mz,cat=0.83 (for terrain category 3)Ms=1Mt= 1Vdesθ= 60*0.95*(1*0.83*1*1) = 47.31 m/sAerodynamic Shape FactorValue of Cfigshall be used in determining the pressures applied to each surface. The wind actioneffects used for design shall be the sum of values determined for different pressure effects such asthe combination of internal and external pressure on enclosed buildings. (section 5.1)For an enclosed building:-external pressures: Cfig,e=Cp,eKaKcKlKp -internal pressures: Cfig,i=Cp,iKc -Cfig = Cfig,e- Cfig,iThe area reduction factor Ka was taken to be 0.8Cdynwas taken to be 1Because of the dominant opening in the roof, the internal pressure co-efficient can be taken aseither 0.0 or -0.3, whichever is the more severe for combined forces.
You've reached the end of your free preview.
Want to read all 7 pages?
- Two '17
- Dead and live loads