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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.
“The Advance”2 pages
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here with part of the bridge turning upside down and over next to Pier 4 here which could be on the West Virginia side. The bridge seemed to break in two and fall straight down ..." and then "this part here, which is the channel span of the bridge, seemed to turn completely upside down, partially, over to about where the center of the span would be (panel 30) and then on farther back (panel 38 or 40 in the record), it seemed to break in two and fall straight down at this point. I would say within fifty or seventy five feet of the towers here on the West Virginia side it broke in two and fell straight down" ..."It dropped straight down with this portion of the roadbed here still clinging to the pier here." (It is to be noted that under subsequent questioning as to which way the Ohio tower rotated, Mr. Britton confirmed that he did indeed mean clockwise as viewed from above.) The break in the main span just west of the West Virginia tower observed by Mr. Britton could have occurred after failure of the "cantilever" effect, since if a length of some 300 feet started to fall with its east end supported at the tower, the inertia forces do produce a maximum moment at about the one third point. Other eyewitnesses were either at the intersection west of the Ohio end of the bridge or at the traffic signal at 6th and Main Streets in Point Pleasant at the east end. Neither of these positions affords a view of the entire length of the structure. The testimony of these witnesses is,however, in general agreement on the sequence of collapse. One witness who was at 6th and Main Streets in Point Pleasant said (written statement by Miss Lyda Smith) in part, "I saw the 'girders' from the Silver Bridge start to fall upstream slowly. Then the cement floor of the bridge (West Virginia side span) started to hove up in the middle and then there was a flash of light overhead on the electric wires." ..."the bridge flooring beyond the approach broke up into large cakes and buckled up." This is confirmed by one other witness (Stephen K. Darst, transcript pp. 149 et. seq.), who also noticed that the north eyebar chain in the West Virginia side span swayed north and south several times, followed by the south eyebar chain in a similar motion just before the collapse of this part of the structure. A summary of the experience of the survivors from vehicles which were on the bridge at this time of collapse is presented in Figure 36. With respect to vibration experienced before the collapse, there are inconsistencies. Those near the Ohio end reported both vertical and horizontal motions of the eyebar chain between the chain bent post
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