SS-H-2
NATIONAL TRANSPORTATION SAFETY BOARD
WASHINGTON, D. C. 20591
HIGHWAY ACCIDENT REPORT
Adopted: December 15, 1970
COLLAPSE OF U. S. 35 HIGHWAY BRIDGE
POINT PLEASANT, WEST VIRGINIA
DECEMBER 15, 1967
I. FOREWORD
This final report by the National Transportation Safety Board supplements the interim report issued October 4, 1968, entitled "Collapse of U. S. 35 Highway Bridge, Point Pleasant, West Virginia, December 15, 1967," File SS-H-2. The interim report included descriptions of the design, construction, operation, and maintenance of the bridge from its completion in 1928 until its collapse in 1967. Detailed descriptions of the collapse of the bridge were given in the interim report, based upon documentary evidence and witness testimony as presented at the Safety Board's public hearing held in Charleston, West Virginia, May 10 through May 13, inclusive, 1968.
As stated in the interim report, it was determined that the fracture in suspension chain eyebar 330 (north bar, north chain, Ohio side span) was essential to the catastrophic stage of the collapse, but the cause of the fracture had not been determined. Eyebars 330 and its sister eyebar 33 were located in the north suspension chain of the bridge between joints C11 and C13. C13 was the first joint west of the Ohio tower. The north leg of the Ohio tower was joint C15N.
The fracture occurred in the lower half of the head of eyebar 330 in joint C13N. The line of this cleavage fracture was at right angles to the axis of eyebar 330. Then a ductile fracture on the opposite side of the eye from the cleavage fracture resulted in the complete separation of eyebar 330 from joint C13N. It was established that eyebar 33 had slipped from the eyebar pin at joint C13N at some time during the separation of the north eyebar chain at joint C13N. It was not known at the time of issuance of the interim report whether the fractures in eyebar 330 preceded the separation of eyebar 33 from the pin.
When the north eyebar chain was separated at joint C13N, total collapse of the bridge was a certainty due to its design with the towers resting on rocker seats.
Prior to issue of the interim report, the Safety Board's Structural Analysis and Tests Group of the investigative team began supervision of an extensive series of field and laboratory examinations to determine the mechanism of failure and the cause of the fracture at joint C13N. Those examinations were completed in the fall of 1970.
The Safety Board issued a press release on December 31, 1968, describing the discovery during laboratory examinations of evidence of a series of minute cracks penetrating to the interior of the fractured head of eyebar 330. It was stated that stress corrosion was suspected