I-35W Bridge, 2007: What the Official Report Found

At six oh five PM on August first, 2007, an eight-lane interstate bridge full of rush-hour traffic dropped one hundred eight feet into the Mississippi River. The National Transportation Safety Board concluded the gusset plates at the U10 and L11 truss nodes — specified at half an inch thick by Sverdrup and Parcel in 1965 when they should have been twice that — could no longer carry the weight of decades of bridge modifications combined with seven hundred thousand pounds of construction materials staged on the closed southbound lanes that day. Source: NTSB Highway Accident Report NTSB/HAR-08/03 — Collapse of I-35W Highway Bridge, Minneapolis, Minnesota, August 1, 2007 (178 pages). Search ntsb.gov for "HAR0803". Chapters: 00:00 6:05 PM, 108 feet into the river 01:05 Section 1 — The moment of collapse 02:31 Section 2 — Contributing construction loads 04:38 Section 3 — The gusset plate failure 06:55 Section 4 — The 1965 design error 08:21 Section 5 — Forty years of inspection gaps — This video uses AI-generated audio and visuals (NotebookLM). Every fact, number, and quote is drawn from the primary NTSB investigation report cited above. The Official Record — every incident leaves a record. We read it.