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This is the final highway accident report (NTSB-HAR-71-1) from the National Transportation Safety Board, adopted in December 1970. It covers the collapse of the U.S. 35 bridge between Point Pleasant, West Virginia, and Kanauga, Ohio, on December 15, 1967, which killed 46 people. The Board found that the cause was a cleavage fracture in eyebar 330 at joint C13N. That fracture grew from a flaw produced over 40 years by stress corrosion and corrosion fatigue, in a spot that could not be seen or found by inspection.
“Cooper”1 page
by a combination of this general northward movement and its own northward movement due to the counterclockwise rotation of the deck, struck the crotch of a tree just west of panel point 9, and about 10 feet north of its final resting place. In the main span the loss of support from the south chain and the displacement of this chain to the north prevented the development of effective cantilever action from the West Virginia tower. When the south leg of the Ohio tower had rotated approximately 50 degrees to the north, the south chain contacted the north tower leg or bracing and a series of multiple fractures occurred in the south chain just east of panel point 17. This was apparently followed by additional multiple fractures in the eyebars of the south chain just west and east of the West Virginia tower. This resulted in a complete loss of support for the south side of the main span which might otherwise have cantilevered from the West Virginia tower. The consequent overloading of the north truss east of panel point 30 produced multiple cleavage fractures in the north chain just west of the West Virginia tower. The entire east half of the main span was now free to fall with but little rotation. Apparently additional multiple cleavage fractures occurred in the lower chord of both trusses as the west end of this portion fell to the water, with the result that only the three panels closest to the West Virginia tower remained intact. ## Step 7 Time = 6 to 10 seconds With the loss of the south chain just east of the West Virginia tower, the south side of the West Virginia side span was free to fall. The north side of this span was in a lifted position at this instant. With the sudden loss of the north chain just west of the West Virginia tower, the tower began rotating toward West Virginia, ramming the West Virginia side span violently against the West Virginia approach span girders. This resulted in the shearing of the pins in the toggle links at the West Virginia tower, and the rupture of both West Virginia chain bent posts at the level of their connection to the lower chord. The north chain in the West Virginia side span was now also ineffective. The westerly portion of this chain apparently remained attached to the north leg of the tower long enough to impart a considerable clockwise rotation to the deck before it parted. This portion of the deck, and the north stiffening truss, came to rest in the water with the north face of the truss upward. It appears that the West Virginia tower was the last part to fall into the water. It fell toward West Virginia and slightly downstream of its normal position, portions of the portal bracing landing on top of what had been the north edge of the deck system. Meanwhile at the Ohio end, the northward rotation of the south tower leg had reached its maximum extent so that the saddle was perhaps
Document, cited by the archive. The PDF is mirrored here; the original link is under it. The text was read from the page images by an OCR model; expect the odd misread word. 202 pages are in the text index: search them above, or from the library's search.