WORLD TRADE CENTERTHE ENGINEERING RECORD
NORTHEAST VIEWORIGINAL 7 WTC
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Columns · beams · lower bracing

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Floor 1 slab reference · foundations below

LOWER BUILDING · SOURCE CONTEXT

DRAWINGS → STEEL MEMBERS

Cross-referenced framing

The model follows WTC 7’s own perimeter framing. Columns and beams use the same plate-section geometry method as the tower model, with WTC 7’s source layout and member families.

Plan
All 82 upper column centers are controlled by original drawing dimensions: 54 directly transcribed and 28 derived from dimension chains. Tier-specific offsets are retained where transcribed; carrying the control plan through other tiers remains a display assumption.
Columns
Original schedules supply size changes through the perimeter and interior columns above floor 7. Thirty-six shop-verified reinforcing plate pairs are shown; other recorded plates remain unrendered where their physical end positions or cuts are unresolved. The 24 upper interior-column starts use source schedules and verified shop interfaces. Lower support paths remain incomplete.
Floor frame
Perimeter spandrels, primary interior girders and the transcribed office beams use source section designations and erection steel datums. Built-up girders retain their plate dimensions and openings; the core girder bays change at floor 25. Special floors and local framing are still being completed.
Base & roof
All four lower braced walls, the transcribed lower core frame, three transfer trusses, upper belt braces, inset south roof frame, twelve sloping W14 supports from Floor 46 to the shop roof reference datum, twelve W8 ties, the west bulkhead, twenty-one shop-verified local roof beams and two Floor 47 shaft beams are represented. The source links distinguish design members, erection substitutions and unresolved support details.
Lobby levels
The cyan grid marks the Floor 1 slab at EL 309′3″, not a surveyed street surface. Architectural A6 places the street-lobby finish 4 inches above it. A7 identifies Floor 2 as a mezzanine open to the lobby; A8 places the Floor 3 main-lobby finish at EL 335′0″, 6 inches above its slab. Floor 4 has a large south atrium opening. Streets slope and step around the building. Foundation steel extends below the Floor 1 reference, along with first-floor beams and parts of the existing substation. A separate dashed outline now locates the occupied substation area, traced proportionally from NIST Figure 2–4 and checked against A6. Its displayed top uses the S25 roof datum; local steps and lower vaults remain unresolved. The original walls, fill and enclosure panels are not reconstructed. Numbered markers identify the existing substation and the real Floor 4 lobby opening. Floor 4 side-wing beams and opening edges now follow E4 and individual shop pieces; remaining local dimension conflicts are recorded with the members.
Still incomplete
This is a drawing-based reconstruction in progress, not a complete fabrication model. Remaining work includes floor 1–6 interior beams, existing substation columns and framing outside the floor 5–7 core. The eight north MG27 girders, MG53 assembly, lower78A column pieces and additional first/second-floor beams are included. MG23’s primary plates have provisional vertical placement: its shop note differs from the adjoining support drawings by two inches. Secondary framing on computer floors 21–23, local floor changes, eleven outer roof tube spans, roof end cuts and connections still need work. Fourteen billed sloped-post pieces are not yet assigned to the twelve registered P10 stations. Unresolved dimensions are identified in member records. Floor and roof guide lines trace the approximate architectural envelope; the source-sized south roof steel uses separate drawing worklines.
NIST Fig. 2-3 · Column and floor-framing plan ↗NIST §2.4.6 · Perimeter moment frame & column trees ↗S8 / E12–13 / S15 · Released structural drawings ↗41 released structural drawings · FOIA 11-209 ↗A6–A8 · Original lobby and mezzanine plans (architectural release) ↗Dimensioned column positions and registration ↓Wind-girder sizes and section sources ↓Lower braced-wall members and source datums ↓Perimeter beam records and source cross-reference ↓Original floor and steel elevations ↓Upper column sizes and splice datums ↓Column sizes from floor 7 to 23 ↓Primary interior girder records ↓Floor 22–24 belt bracing ↓Upper perimeter and inset roof frame ↓South roof-front steel and pending tube spans ↓Verified Floor 46–roof local beams ↓Verified Floor 47 shaft beams ↓Interior column sizes and splice records ↓Shop-verified column reinforcing plates ↓Core bracing and transfer trusses ↓Lower core columns and baseplate datums ↓MG23 · Primary plates and unresolved elevation discrepancy ↓Lower 78A · Original column pieces and cap ↓North supports, MG27 girders and floor 4 beams ↓Dimensioned office-floor beams ↓Built-up girder plates and openings ↓West roof bulkhead frame ↓Cooling-tower support beams and posts ↓Floor-by-floor drawing comparison ↗Upper perimeter drawing audit ↗