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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.
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of cleavage and shear as the fracture progressed through the cross section of the rivet. No evidence of pre-existing cracks or flaws in the rivets was found. The conclusion of this report states in part "Strain-hardening of the rivets occurred as stress was applied. In the process of fracturing, the energy absorbed was evidently high and the fracture stress was higher than the ultimate* strength of the material. Accordingly, the fracture behavior could be characterized as being ductile. It appears that fracture of the rivets resulted from overloading of the steel in the plastic range. The appearance of the fracture profiles indicates a relatively high strain rate." h. A number of other minor examinations have been conducted by the National Bureau of Standards laboratories. Significant data resulting from these investigations are contained in the official records of the investigation, as follows: (1) Measurements of the deformations in the C13 heads of eyebars No. 33 and No. 330. (2) Miscellaneous metallurgical data on eyebar steel and A-7 steel examined. (3) Results of an attempt to identify pin C13N by "ballistic matching" of markings in eyebars and in pins available. 2. Studies at the Battelle Memorial Institute (Columbus, Ohio) The Battelle Memorial Institute was requested to conduct extensive studies to supplement those conducted at the National Bureau of Standards for the following purposes: (1) To determine whether small cracks on the inside surfaces of the eyebar pinholes existed in other eyebars in the Point Pleasant Bridge wreckage. (2) To assess the fracture toughness characteristics of the two steels used in the structure in order to determine whether pre-existent cracks found in various members by the National Bureau of Standards were of the critical size necessary to induce brittle fracture at stresses computed to have existed in the structure at the time of collapse. *The author of the report apparently intended this to mean the static tensile strength of the material.
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