For the composite parts method, first break the wind load
into two parts: a uniform load of 40 lb/ft and a triangular load
of 0 lb/ft at the base and 80 lb/ft at the top of the building.
The force resultant of the uniform load and its location is
F1 = 40 (500) = 20,000 lb
y1 = 250 ft
The force resultant of the triangular load is
F2 = 0.5 (80) (500) = 20,000
lb
Its location is two-thirds of the distance from the vertex to the peak
value
y2 = 2/3 (500) = 333.3 ft
Nest, combine these two forces into a single force FR located
at the position y'.
FR = ΣF
= F1 + F2 = 40,000 lb
Its location is given by
Substituting F1, y1, F2, and y2
and simplifying the equation gives
y' = 1.166 x 107 / 40,000
= 291.7 ft
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