# Above-Floor7 perimeter review against original drawings

This review found one resolvable schedule ambiguity and a substantive roof-front steel gap. A subsequent source-controlled pass added the twelve sloping support worklines and twelve ties in `wtc7_roof_front_frame.json`; all eleven outer tube bays now have E47 shop-mark assignments but remain pending because their transverse workline and physical end points are unregistered. It found no completely omitted perimeter floor band between Floors 8 and 47/roof in the current datasets. A continuous member count is a coverage check, not evidence of complete fabrication accuracy.

## Source coverage and results

| Original source | What was checked | Result and limits |
|---|---|---|
| S8, E12/13 | WG1–58 registration on four sides | 15 west,13 south,14 east and16 north bays. Directed model IDs retain the original adjacent columns. Interior topology is outside this perimeter registration. |
| S15, all retained native table crops | All16 weight bands across WG1–58; blank WG59–64 | The 927 directly legible cells agree with the transcription. WG55 at38–39 remains ambiguous in S15 itself. MOM rows and connections have not been transcribed. |
| E38/39 native plan | WG55 between C55 and C54 | Explicit W36×194, mark A2355. Resolves the two previously unassigned members. The S15 source ambiguity remains preserved in metadata. |
| S9/S12; special-framing dataset | Floors21,22,23,46 | Each special level has58 registered perimeter bays. Their topology is separately emitted rather than a missing typical-floor band. This check does not certify all interior beams or local offsets. |
| E122, all four native exterior elevations | Belt22–24, brace bays and moment-frame chords | Source shows alternating diagonals across all58 bays in each of two storeys, including the four moment-frame regions. Current116 diagonal records and12 chord overrides agree with this topology. Connections and gussets remain incomplete. |
| S17/S18, retained schedule transcription; E117/E118 | Perimeter columns finished7 through upper tiers | All58 column paths are continuous in the data;522 lower/mid segments meet742 upper segments without a nominal vertical gap. A separate final-band S18 check matches all58 roof-tier cells:46 W-sized segments and12 blank C16–27 cells above the south setback. See `roof-perimeter-column-audit.md`. Every original erection piece and shop cut has not been independently reconciled. |
| S18 south upper group; E118 | Original C16–27 roof stops | These original columns terminate at46; blank roof-tier cells are intentional. Separate inset P-posts carry the higher roof-front framing. Extending the old column line to roof would be incorrect. |
| S12 post schedule; S13/S14; E46/E47/E48; shops4238–4240 | Roof front and end returns | The134-member roof frame covers two58-bay WG courses,4 end returns and14 vertical posts. A separate detail frame now adds12 P10 sloping W14 worklines from Floor46 to the shop roof reference and12 W8 ties. Exact fabricated cuts and shop-to-station assignments remain open. |
| E47 native perimeter strips; S13 plan; S15 schedule | All 58 Floor 47 wind-girder bays and four corner transitions | E47 and S15 confirm west WG1–15 as W30×99, south WG16–28 as W24×76, east WG29–42 as W33×118, and north WG43–58 as W36×150. WG15/16, WG28/29, WG42/43 and WG58/1 meet at their corresponding corners. No plan section or bay-topology mismatch was found; fabricated ends remain open. See `roof-frame-audit.md`. |
| E48 native roof perimeter strips; S14 WG marks | All 58 roof wind-girder bays and four corner transitions | E48 confirms west WG1–15 as W30×99, south WG16–28 as W24×76, east WG29–42 as W30×99, and north WG43–58 as W36×135. WG15/16, WG28/29, WG42/43 and WG58/1 meet at the corresponding corners. No plan section or bay-topology mismatch was found; fabricated end cuts remain open. See `roof-frame-audit.md`. |
| Shop4196/4197 and4149 | Example terminal columns/roof-post interfaces | Native details show milled/capped ends and local heights. These checks confirm that general floor/roof display planes are insufficient to certify every terminal cut. No uncertain fraction was promoted to a new exact boundary. |
| Shop4259; E47 section A–A and south plan | Roof-front cross ties and outer tube line | 12 W8×24 ties are rendered in the separate roof-front frame. All 11 TS12×6×½ outer horizontal bays have plan shop marks and shop lengths, retained as pending source records until their transverse centerline and physical ends are registered. They are structural steel. |
| E48 east plan; shops4480/4250/4243/4479 | Roof east-side perimeter-connected steel | A/B/C4480 W21×68, D/G4480 W24×62, H4480 W24×55 and A4250 W24×117 reach P37–P32 or WG32–31 from the C79–81 workline. A4243/W36×150 runs diagonally from P44 to C79 and supports D4479/W21×68, which reaches P38. The diagonal fixes D4479's previously unresolved west endpoint. All nine new east-side worklines close shop overall dimensions within 0.04 inch and are rendered in the upper-local frame. |
| E48/S14 west plan; shops4471/4483/4485 | Roof west-side perimeter-connected framing | A4485/W18×40, B4485/W16×31 and C4485X/W16×26 run from posts P2–P4 to H4483/W27×84. D4485/W36×135 runs from P5 to the A4471/C58 support line. H4483 spans P56 to D4485 at the P5 row; its three shop attachment stations close the P5–P2 row spacing within 0.005 inch each. B4471/W30×99 runs from WG56 at 9′8″ east of P56 to D4485 at the P5 row. Its 39′6.267″ support-axis workline exceeds shop 4471/B's 39′4 1/16″ overall and 39′3½″ material cut by 2.205 and 2.767 inches, respectively. H4483's overall is 0.642 inch shorter than its workline. All six plan worklines are rendered; their physical end allowances remain open. |
| E46 north-strip witness; shop4474/A | Floor46 P55-to-core framing | E46 places A4474/W36×170 9′7″ east of P55. Its north wind-girder-to-core-row plan workline is 52′9″, matching the shop overall. It is rendered once in the upper-local package; end cuts and connections remain unregistered. |
| E47 north-strip witness; shop4452/A | Floor47 P55-to-core framing | E47 places A4452/W24×76 10′2½″ east of the P55 axis, giving x = −88.937500 ft; the north wind-girder-to-core-row workline is 52′9″, matching shop 4452. The beam is rendered once in the upper-local package. Adjacent E47 `FUTURE` framing remains excluded. |
| E48/S14 southeast plan; shops4275/4478/4495 | Roof southeast return and secondaries | S-14 and B4275 identify the P27A–P27B return as W18×35; the roof model section was corrected from W16×26. B/C/D4478 match existing WG26/27/28 and were not duplicated. D4495/W16×26 reaches P29 and G4495/W16×26 reaches the WG29–28 midpoint from the P27 return, closing shop spans within 0.021 inch. B/C4495 lack independent absolute west z stations; their shop-implied separation differs from E48's 8′6″ by 0.477 inch, so they remain unrendered. |
| S17, E117 and reviewed perimeter shop sheets | Upper perimeter column reinforcing plates | E117 identifies shop marks for all 20 reinforced perimeter schedule records. A1502's hand-revised 12×1×24′10″ PAB bill and upper mill datum establish one C55 F9–11 pair. Nineteen perimeter records remain unresolved. C5/C8 flange shops have multiple short cuts per tier; the other C45/C55 shop PA/PAA bills still conflict with the schedule width or lack both physical ends. |

The upper-local package contains 26 modeled beams: four on Floor 46, one on Floor 47, and twenty-one at the roof. Its coverage remains limited to source-registered worklines.

## Implemented correction

`tools/build_wtc7_wind_schedule.py` and `site/data/wtc7_wind_schedule.json` now assign2030 typical-floor wind girders. The S15 table still contains927 direct readings and one visually ambiguous cell; that last cell has an explicit E38/39 resolution record and crop. This distinction preserves source provenance.

## Physical omissions and unresolved geometry

1. **Roof-front outer tube and connection workpoints.** S12 identifies P10 as W14×109, sloping from Floor 46 to roof. E47 section A–A shows 20° inclination, W8×24 ties and the outer TS12×6×½ line at EL907′0. Shops 4238–4240 confirm the full sloping construction but bill 14 W14 pieces against 12 registered P10 stations; their piece-to-station assignment is unresolved. Shop 4259 gives 12 ties (4 A4259, 6 U4259, B4259X, T4259X) and 11 tube spans. E47 resolves their west-to-east bay sequence as D, G, G, H, K, G, G, G, M, N, P. The twelve dimension-controlled sloping worklines and twelve ties are emitted; the tube line and connection geometry still need registered transverse and end workpoints. See `roof-front-frame-audit.md`.
2. **Perimeter column reinforcement.** Fourteen mid-tier and six Floor 7 splice cells include reinforcing-plate cross sections. E117 assigns their shop pieces. C55 F9–11 now has a verified pair from the revised A1502 bill; the other 19 cells still lack registered longitudinal bounds, reconciled widths or physical cut positions. The C5/C8 shops split flange plates into short cuts. See `upper-column-reinforcement-audit.md`.
3. **Splice and terminal boundaries.** The58 finished7-to-first-splice bridges use the current finished7 interface and the drawing's default3′6″ splice convention. Individual sloping elbows and exceptions remain unverified. General floor/roof planes are also used for terminal display boundaries; shop-specific caps, mill cuts and local top levels require further work.
4. **Connections.** Wind-girder moments, bolts, stiffeners, welded connection plates, column splice hardware and facade attachment steel have not been exhaustively reconstructed. Their absence does not authorize filling the model with a facade surface.

The evidence does not support describing the complete model as1:1 to all blueprints. Above7 it has continuous principal perimeter coverage, while the roof-front tube line and fabrication details remain incomplete. Lower front/substation coverage is a separate audit and is not included in this conclusion.

## Reproduction and evidence

Run `python3 tools/build_wtc7_wind_schedule.py` and `python3 tools/build_wtc7_roof_front_frame.py`. The wind builder validates58 bay registrations,928 schedule positions,2030 unique assigned members and section-catalog matches; the roof-front builder validates the separate12/12/11 source inventory and the 20° workline closure. Relevant native crops are under `above7-review-crops`; full table, belt and roof crops remain under `wind-source-crops`, `belt-source-crops` and `roof-source-crops`. Raw TIFFs remain in the verified original FOIA releases outside the site repository.