Dead Loads Dead loads consist of the weight of allmaterials of construction incorporatedinto the structure (i.e. tower and windturbine).
Wind Loads Wind loads arerandomly applieddynamic loads. It depends on thewind speed, shapeand height of thestructure andtopographic of theregion. Most calculationsusing US customarysystems, which isapplicable to ASCE7-02 and ASCE 7-05.
Basic Wind Speed, Vand Wind Directionality Factor,Kd The basic wind speed, V, assumed as134.216 mph or 60 m/s. The wind directionality factor, Kd, forwind turbine tower is 0.95 for towerand 0.85 for the DS wind turbine.
Importance Factor, I An importancefactor, I, for thewind turbine tower(Building CategoryIII or IV) is 1.15.Building Type ICategory I -Buildings and otherstructures with lowhazard to human lifein the event offailure, such asagricultural facilities.0.77Category II – Otherbuildings.1.00Category III and IV -Buildings and otherstructures with asubstantial hazard tohuman life in theevent of failure, suchas hospitals,communicationtowers and powergenerating stations1.15
Surface Roughness andExposure It is assumed thatthe tower would beinstalled on aterrain with surfaceroughness andexposure categoryof C (town/ smallcity).ExposureCategory B,ex. 臺北ExposureCategory C,ex. 板橋ExposureCategory D,ex. 金門
Velocity Pressure ExponentCoefficient, Kz Velocity pressureexponent, Kz, depends on the siterelative height tothe ground, z. This means forrooftopstructure, z, wouldbe the total heightof the componentand the building itsinstalled.Nominal heightabove ground level,zK z forExposureCft m0-15 0-4.6 0.8520 6.1 0.9025 7.6 0.9430 9.1 0.9840 12.2 1.0450 15.2 1.0960 18 1.1370 21.3 1.1780 24.4 1.2190 27.4 1.24100 30.5 1.26
Topographic Factor, Kzt andForce Coefficient, Cf The value of Kztwas taken as 1 withassumption flatregionenvironment. The values of Cfwere taken fromFigures 6-19 and6-21 of the code. The values are 1.2for the tower and1.1 for the windturbine.
Velocity Pressure, qz The velocity pressure, qz, evaluated atheight z shall be calculated by:
Gust Effect Factor, G Gust effect factor, G, could becalculated by Eq. 6-4 of the code. This factor increased with structureheight.
Design Wind Loads, F Design wind force foreach component shallbe determined by: Moment because ofwind force calculatedas:FWTFTOWERabbFaFM WTTOWER