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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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samples removed from the lower end of this specimen indicated that its composition and properties were typical of the other A7-24 material in the structure (See Appendix B). The examination of the cleavage fracture surface showed that it had propagated from a pre-existent crack in the southwest corner of the cross section, that the propagation of the crack had occurred at high velocity and apparently under the influence of a high loading rate. Two photographs of the fracture surface are given in Figures 12a and 12b. The pre-existent crack surface was metallurgically examined and found to be decarburized and to be characterized by rather large grain size. This crack area also showed evidence of tightly adhered particles of both aluminum and orange colored lead paint. An analysis of these paint particles was conducted by the FBI laboratory. The report of the laboratory is included as an appendix to Reference 21 and indicates that: (1) The fracture surface in this area includes small areas of both aluminum and orange colored lead paint which the evidence indicates to have been deposited when wet. (2) The composition of aluminum paint on the fracture surface corresponds to those on the outer layers of a total of three layers found on the area of the non-fractured outer surface of the specimen. The orange paint in the fracture surface corresponds with the lowest of five layers on another portion of the outer non-fractured face. These findings were the subject of lengthy discussions within the working group, since the presence of paint in this region of the fracture surface would appear to indicate that the pre-existing defect extended to the outer surface and might have been a crack large enough to be observed during inspection or painting operations. The possibility that this fracture acted as a "trigger" producing shocks on the eyebar chain was considered. The distortion of the cross section of the specimen, however, indicates that the fracture occurred at a time when there was considerable torsion as well as tension on the member. The narrow faces of the bar are distorted at an angle of about 3-1/2 degrees with respect to the normal to the wide faces. At the time of preparation of this report, communications from the National Bureau of Standards indicated that the cleavage fracture
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