13 Dead. The Gusset Plates Were Half as Thick.
Chapters
About this video
The I-35W Mississippi River bridge collapse on 1 August 2007 came down to undersized gusset plates at the U10 nodes, roughly half the required thickness. This investigation walks through the NTSB probable cause, the added dead load from deck modifications, and the concentrated construction loads that afternoon, explaining how a non-load-path-redundant deck truss unzipped in seconds, killing 13 people and injuring 145 across 111 vehicles. Chapters: 00:00 6:05 P.M. 00:14 Three questions 00:32 I-35W 00:48 The plate 01:02 Node U10 01:18 Half as thick 01:34 0.5 versus 1.0 01:48 Sverdrup and Parcel 02:03 Forty years 02:16 Two more inches 02:32 Structurally deficient 02:48 Four lanes closed 03:05 The last load 03:23 The second it went 03:42 The unzip 03:56 111 vehicles 04:11 Probable cause 04:31 No spare path 04:46 What they looked at 05:02 Along the rivets 05:19 Half the plate, half the capacity 05:37 Demand and capacity 05:55 Fracture-critical 06:11 The recommendation 06:27 Fourteen months 06:43 Half an inch
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