Research — Auto Demo · Precomputed (draft, unvalidated)

H-frame: raise the crossbrace — auto

No controls here: six short stories play on their own. The bulletin example shows the lower brace joint governing and the crossbrace next. Raising the crossbrace keeps that point governing; lowering it hands the limit to the crossbrace itself. A stronger pole class changes only a point that never governed. A double crossbrace lifts the crossbrace span and another point takes over. Use Pause, or the story and step buttons, to stop on any frame. Nothing is marked pass or fail: the point that governs is outlined.

Story

Draft, unvalidated harnessIllustrative geometry: the harness has no pole-geometry modelPoint D is not validated

Elevation · heights and pole spacing to scale, pole widths drawn about 1.7 times wider

What limits the span · maximum horizontal span at each point

Span against crossbrace height · one dot per exported stop

governs: the smallest span of the five (an accent outline and the word, never a pass or fail color)next: the second smallestthe gap between them (exported)Bar and dot colors only say which point it is.

Every point at this step · the governing row is outlined

Rule column: the equation the data file cites for each span. Rank, ‘governs’ and ‘next’ are the exporter's comparison. Uplift sits below the dashed line because it is a foundation check and takes no part in the ranking.

How the checks read it

Reference check · does the harness reproduce the bulletin?

The harness's own exporter ran these before writing the data file. ‘= ok’ means the computed value is within the stated tolerance of the expected one; ‘≠ not ok’ is a known gap and is shown as one. Only the first group is a bulletin worked example; the formula-consistency group is hand-computed regression values and is not a bulletin number.

Every point · the first reading, the change, the last step

Columns are step labels. The spans are harness outputs read from the data file; ‘governs’, ‘next’ and the gap are the exporter's comparison of those five spans. ‘First to last step’ compares the first and last columns only (same, longer or shorter).

Precomputed results:every verdict, required value and margin on this page was computed by the real Python harness at export time and is played back from a data file. The page runs no harness logic and holds no standards tables, and it never interpolates between exported values. Not a live API call. Precomputed by the real utm-agent-harness h_frame functions (commit e61dd9d) at export time and played back from a data file. The harness is a DRAFT with no human subject-matter-expert sign-off; nothing here is a design or a compliance determination. The functions COMPUTE spans and never judge, so there is no pass or fail anywhere on this page: ‘governs’ (the smallest of the five spans), ‘next’, the gap and ‘uplift below’ are the exporter's own comparison (demo logic), and no color is chosen by a verdict. ONLY Structure 4 (RUS 1724E-200 Sec 13.f, Douglas Fir 80-2, 161 kV, NESC Heavy 4 psf) has a bulletin worked example; Structures 2 and 3 are formula-consistency tier and are computed on the Structure 4 geometry. Point D is NOT validated: the bulletin quotes 811 ft and the harness does not reproduce it (reference check HSD, shown as not ok). The geometry is illustrative: the harness has no pole-geometry model, so moving the crossbrace uses a straight taper from 7.96 in at the top to 15.64 in at the groundline and the bulletin's internal offsets held fixed while the bracing assembly slides (back-solved from the bulletin's quoted numbers; not validated), and the wire attachment heights are illustrative. Pole class changes only the groundline capacity. Wind: the bulletin's wire loads at 4 psf are scaled linearly with pressure (demo logic). Uplift uses the bulletin's W1 and pole weight as inputs and is shown beside the ranking; the bearing check is not included. Domain maturity: schema draft, unvalidated; no structural or transmission-line PE has reviewed it.Real functions this maps to:horizontal_span_at_a_ft, horizontal_span_at_d_ft, horizontal_span_at_e_ft, horizontal_span_at_b_ft, horizontal_span_at_e_structure_2_ft, horizontal_span_at_b_structure_2_ft, horizontal_span_at_e_structure_3_ft, horizontal_span_limited_by_crossbrace_ft, uplift_relationship, groundline_moment_capacity_ft_k.Not modeled: a real pole-geometry model (diameters, taper and the placement of the bracing are derived, not measured), the bearing check (Eq. 13-19g), conductor sag and ice, the iterative deflection re-check, any structure type other than the Structure 2, 3 and 4 H-frames, and whether a given span is acceptable. Heights and pole spacing are to scale; pole widths are drawn about 1.7 times wider; the string, wire and person are pictures, not results.See also:H-frame: raise the crossbrace, interactive with free play · Structure loading walk, hands-off