Figure 1 - Tip Load Components

The total tip load force on pole is the vector sum of the following components:

e.g. In a no wind condition, only longitudinal conductor forces will contribute to the tip load of pole.

Transverse Wind Force on Conductor

The transverse wind force on conductor is calculated as follows:

Where:

Fc = load on structure from wind on projected wind area of conductor

qz = design wind pressure on conductor (kPa)

Cd = drag coefficient of conductor. This is defaulted to 1 in the absence of more accurate information.

L = conductor span length (m)

d = conductor diameter (m)

SRF = span reduction factor see article on SRF

α = angle between wind direction and the normal to the conductor (°)

In Directionless Tip Load Calculation method, the wind angle is taken as the worse case for each conductor , i.e.α = 0°

In Direction Sampling Calculation method, the wind angle is sampled at a discrete number of times around the pole, as defined by user, i.e.α = 5°, 10°, 15°, 20° etc

The longitudinal conductor force H, can be derived from the following principal:

Where:

T = tangential or axial conductor tension (N)

H = horizontal component of conductor tension (N)

V = vertical component of tension (N)

H can be derived with the MacLaurin's series approximation of the catenary equation:

The wind force on a cylindrical pole is calculated as follows:

Where:

Fpole = Wind load on pole (kN)

P = design wind pressure on pole (kPa)

OD = average outer diameter of pole (m)

h = height of pole above ground (m)

Reference:

AS/NZS 7000:2016 Overhead Line Design
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See also:

Sag Tension Calculation

Pole Plant Calculation