It Collapsed Weeks Before Anyone Saw It Fall

Five years after Champlain Towers South collapsed, NIST's National Construction Safety Team released its technical findings — and the mechanism they describe began three weeks before anyone knew to be afraid. This file walks through the federal investigation, start to finish: the two garage-column connections that failed first in early June 2021, the full-scale laboratory tests that reproduced the exact fracture, and the four converging causes — design, construction, added load, and corrosion — that NIST says explain why the margins against failure were too narrow from the start. This is Video #004 in THE FAILURE FILE's ongoing investigation — a direct continuation of Video #002, "The 2018 Report That Documented The Damage." Watch that one first if you haven't, or come back to it after this. No dramatization beyond what the record supports. No blame assigned beyond what the report states. Just the file, read in full. 00:00 Cold open — three weeks before 02:25 The mechanism: punching shear 06:35 The decision trail — design, construction, and the code that allowed it 10:05 What NIST's final report will still determine 11:55 File status: open Sources / further reading: — NIST NCST Technical Findings, Champlain Towers South Partial Collapse (June 2026) — NIST NCST Investigation Overview (2021–2026) — University of Washington full-scale connection testing summary #EngineeringFailure #ForensicEngineering #StructuralEngineering #DisasterInvestigation #EngineeringDocumentary #NIST #ChamplainTowers #StructuralCollapse #EvidenceBasedDocumentary #TheFailureFile