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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
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## IV. ANALYSIS This section will interpret the field and laboratory investigations with respect to the following questions: (1) Did the structural steels of which the Point Pleasant Bridge was constructed meet the specification requirements, and was the particular steel in members found to contain critical fractures in any way unusual? (2) What were the actual stress levels in critical locations as opposed to the conventional primary stress analysis based on the assumption that the structure is a pin connected, linear elastic system? (3) Was the brittle fracture in eyebar No. 330 the event which initiated the collapse, and have all other possibilities been eliminated? (4) Is the sequence of collapse based upon the assumption that eyebar No. 330 was the initial fracture consistent with the observed types of damage, the positions in which the wreckage fell, and the testimony of witnesses? (5) What was the mechanism by which the crack in eyebar No. 330 grew to critical size? (6) Were the assumptions made in the design of the bridge consistent with the best practice in 1926, and what are the implications of these assumptions in light of today's knowledge? (7) What questions and observations does this investigation raise with respect to the safety of other bridges? ## A. The Properties of the Steels in the Point Pleasant Bridge Two types of steel were used in the main superstructure elements of the Point Pleasant Bridge. The trusses, hangers, towers, and floor system members were fabricated from the common carbon structural steel of that era, manufactured under A.S.T.M. specification A7-24. The eyebars of the chain were made from a special steel of the U. S. Steel Corporation which had been developed a few years earlier and had been used in the eyebars of one other bridge at Florianopolis, Brazil. This steel was basically a heat treated "1060" carbon steel. The eyebars were tested for compliance with the manufacturer's specification as approved by the designers.
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