We = Wv2 + Wh2 + K
where:
We = Resultant loading in pounds per foot of conductor length.
W v = Vertical load in pounds per foot of conductor length, covered with 1/2 inch radial thickness of ice.
Wh = Transverse loading in pounds per foot of conductor length due to a transverse, horizontal wind pressure of four pounds per square foot upon the projected area of the conductor, covered with 1/2 inch radial thickness of ice.
K = 0.29 for bare conductor of copper, steel, copper alloy, copper-covered steel, aluminum-covered steel, and combinations thereof
K = 0.31 for bare conductors of aluminum (with or without steel reinforcement).
In applying loadings to bare stranded conductors, the coating office shall be considered as a hollow cylinder touching the outer strands.
Ice is assumed to weigh 57 pounds per cubic foot. The weight of ice in pounds per lineal foot can be calculated by the formula:
Weight of Ice = 1.243 t (D+t) where:
D = Diameter of conductor in inches
t = Radial thickness of ice in inches
The wind load delivered to the support by the conductor shall be calculated using the wind span S h , which is the average of the two spans adjacent to the support concerned, i.e., Wh x Sh .
For latticed bodies of structures, the actual exposed area of one face shall be increased by 50% to allow for the pressure on the opposite face. This total, however, need not exceed the pressure which would occur on a solid structure of the same outside dimensions. The results obtained by more exact calculations may be substituted for the values obtained in 220 CMR 125.24.
220 CMR 125.24