Research — Illustrative (draft, unvalidated)
Pole groundline moment
A single wood pole resists wind on the pole, wind on the wires, and the unbalanced vertical load, all as moments at the groundline. Drag the span and watch the bars grow toward the dashed capacity line; the span where they meet is the maximum horizontal span the bulletin's quadratic returns.
Factored groundline moments vs factored capacity · TS-1 55 ft pole example data
Candidate horizontal span
Wind pressure
Pole moment capacity · your assumption
The bulletin's TS-1 example uses 204,200 ft-lbs (Appendix F, 55 ft Class 1 SYP at 7.5 ft embedment).
Fixed to the TS-1 worked example: strength factor 0.65, wind load factor 2.5, vertical load factor 1.5, pole top and groundline diameters 8.59 and 14.61 in, 47.5 ft above groundline.
Groundline moment balance
Factored demand at this span
Factored capacity
Maximum span
How the check read it
Client-side port:the logic and table in this page are a TypeScript port of the harness function, checked against values exported from the Python tests. Not a live API call. Domain maturity, quoted from the research page: “Schema draft, unvalidated. No structural or transmission-line PE has reviewed it. Insulator swing, pole capacity, crossarm span and guying are checked against the bulletin’s worked examples; ROW width and galloping are formula-consistency only.” The pole and loading data are the bulletin's TS-1 55 ft Southern Yellow Pine worked example (NESC Heavy loading district, 4 psf, 204,200 ft-lbs); the Python reproduces its worked answers within the tolerances its tests use (Mwp 3,985 ft-lbs ±2, maximum span 423 ft ±3). The harness returns computed moments and a span, never a verdict, and this page draws no pass/fail either.Real function this maps to:
max_horizontal_span_ground_line_method.Not modeled: the Point-of-Maximum-Stress method for poles of 60 ft or more, guyed poles, the iterative deflection-magnifier re-check (Eq. 13-8: the assumed 1.15 is used as given), any pole or conductor other than the TS-1 example data, and whether a given design span is acceptable. Wind pressure and pole moment capacity are the only inputs varied here; the capacity slider is your assumption, not a table lookup, and the bulletin's 204,200 ft-lbs comes from its Appendix F for that one pole class. The bars are the factored terms drawn to scale, not a structural analysis.See also:Pole groundline moment, auto sweep · Insulator swing, interactive