Neara allows for a custom pole strength to be used. This can either be entered directly as a maximum tip load or can be calculated based on the pole dimensions.
To use this feature select a pole and select the check box Custom Pole Strength. To directly enter a maximum tip load select the text box at (1) and enter the value. To calculate this value select (2).
If you click on (2) Calculate from wall thickness then it will bring up a number of parameters which are defaulted to the values of the current pole assuming the pole is not hollow. When you have updated the parameters and then click Apply it will then take the calculated value and put it in the Custom Pole Strength box.
The formulas used to calculate the custom pole strength is as follows:
The first step is to calculate the maximum bending moment.
The second step is to calculate the max pole tip load.
Note that this formula uses the default embedment depth as defined in the pole library (this is the Library free length in the screenshot above). Hence any changes to the pole embedment depth will not change the calculated maximum pole tip load. However the maximum bending is calculated using the max tip load and the default embedment depth, hence any changes in the embedment depth will be caught by the bending moment check of a pole.
For example consider the this scenario where there is a single conductor at 6kN @ 5oC. Note that in reality these poles would deflect however given this is using static the poles won't deflect. The custom pole strength is calculated at 40kN when the embedment depth is 2.35m (2.35m is the default in the library for this pole type). The maximum bending moment in this case is 646 kN.m.
In this scenario the strength reduction factor applied to the pole is 0.15 (defined in the environments), hence the pole has a maximum tip load limit of 40 x 0.15 = 6kN and maximum bending moment limit of 16.15 x 40 x 0.15 = 96.9 kN.m. So if the embedment depth was now reduced to 1m then the structure will still pass the tip load check however will fail on the bending moment check given the bending moment on the pole has increased to 105 kN.m. Note this is a no wind environment at 5oC.
