Documents / Document
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.
Read from the scan by GLM-OCR; expect the odd misread word.
There existed the possibility that wind excitation of the structure might have produced a failure of the Point Pleasant Bridge of the same type as that which occurred in the Tacoma Narrows Bridge in 1940. At the time of collapse of the Point Pleasant Bridge, however, the wind was blowing in a direction parallel to the axis of the bridge and at a velocity of about six mph. Mr. George Vincent, a well recognized authority on the aeroelastic oscillation of suspension bridges as a result of his participation in the investigation of the Tacoma Narrows Bridge failure and his many years of subsequent research on this class of problem, testified at the public hearing in May 1968 that these circumstances made it highly improbable that aerodynamic excitation was the direct cause of the catastrophe on December 15, 1967. Nevertheless, it was conceivable that at certain periods during the lifetime of the structure there may have been wind at right angles to the axis of the structure sufficiently strong to induce aeroelastic vibrations and that these vibrations, if of sufficient magnitude, could have contributed to reducing the life of the structure by fatigue crack growth. The further investigations conducted to examine this possibility are discussed within this report. Among the causes related to external events, the possibility of sabotage had been checked during the initial phases of the investigation. The results of inspections of all of the salvaged vehicles by a team of experts from the U. S. Army Ordinance Group showed no evidence of explosions in any of the vehicles. Subsequent inspections of the structural members at the reassembly site have not produced any indication of explosions in critical members, and no other evidence of deliberate sabotage by cutting or burning has been found. The design of the structure was such that it would be virtually impossible for a vehicle to collide with the tower structure. Examination of the tower legs at the reassembly site showed no evidence of such vehicle collisions. A collision on some part of the stiffening truss was possible. This might have produced large distortions and local deck failures but would not constitute a failure in the critical load supporting structures in the towers and chains. However, the shocks involved in such a collision and the subsequent loads on the eyebar chain could have produced critical failures. The positions of the vehicles known to be on the bridge at the time of collapse makes this possibility remote, in that the deck adjacent to the north truss was occupied by standing traffic from the Ohio shore to the middle of the main span. Had a collision occurred, it is unlikely that it would have escaped the notice of all of the witnesses who survived the collapse of the structure. The eastbound traffic consisted of the two heavily loaded dump trucks and five passenger vehicles moving as a group across the structure. Since eyewitness testimony indicates that this group of vehicles moved continuously from the Ohio shore
Document, cited by the archive. The PDF is mirrored here; the original link is above. The text was read from the page images by GLM-OCR; expect the odd misread word. 202 pages are in the text index: search them above, or from the library's search.