HIGHWAY ACCIDENT REPORT
Adopted: December 16, 1970
COLLAPSE OF U. S. 35 HIGHWAY BRIDGE
POINT PLEASANT, WEST VIRGINIA
DECEMBER 15, 1967
NTSB Number: HAR-71/01
NTIS Number: PB-190202
SYNOPSIS
The U. S. 35 Highway Bridge connecting Point Pleasant, West Virginia,
with Kanauga, Ohio, collapsed at approximately 5 p.m. (EST) December 15,
1967. Forty-six persons died in the accident, nine were injured, and 31
of the 37 vehicles on the bridge fell with the bridge. Twenty-four vehicles
fell into the Ohio River and seven fell on the Ohio shore. There were no
pedestrians on the bridge at the time of collapse.
The initial failure in the bridge structure was a cleavage fracture
in the lower limb of the eye of eyebar 330 (north bar, north chain, Ohio
side span) at joint C13N, the first eyebar chain joint west of the Ohio
tower of the bridge. The cleavage fracture was followed by a ductile fracture
in the upper limb of the eye of eyebar 330 at joint C13N, separating eyebar
330 from the chain. Immediately following the separation of eyebar 330
from joint C13N, the sister eyebar 33 slipped from the C13N joint pin,
resulting in the separation of the north chain at that location. The collapse
of the bridge began in the Ohio side span, moving eastward toward the West
Virginia shore, with the result that within a period of about 1 minute,
the 700-foot center span, the two 380-foot side spans, and the towers had
collapsed.
The Safety Board finds that the cause of the bridge collapse was the
cleavage fracture in the lower limb of the eye of eyebar 330 at joint C13N
of the north eyebar suspension chain in the Ohio side span. The fracture
was caused by the development of a critical size flaw over the 40-year
life of the structure as the result of the joint action of stress corrosion
and corrosion fatigue.
Contributing causes are:
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1. In 1927, when the bridge was designed, the phenomena of stress corrosion
and corrosion fatigue were not known to occur in the classes of bridge
material used under conditions of exposure normally encountered in rural
areas.
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The location of the flaw was inaccessible to visual inspection.
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The flaw could not have been detected by any inspection method known in
the state of the art today without disassembly of the eyebar joint.
RECOMMENDATIONS
The Safety Board recommends that:
1. The Secretary of Transportation expand
existing research programs or institute new research programs to:
a. Identify bridge building materials
susceptible to slow flaw growth by any of the suspected mechanisms;
b. Determine critical flaw size under
various stress levels in bridge building materials;
c. Develop inspection equipment capable
of detecting critical or near critical flaws in standing bridge structures;
d. Devise analytical procedures to identify
critical locations in bridge structures which require detailed inspection;
e. Develop standards which incorporate
appropriate safeguards in the design and fabrication of future bridges
to ensure protection against failures of material such as occurred in the
Point Pleasant Bridge;
f. Develop standards for the qualification
of materials for future bridge structures, using the information disclosed
in this investigation;
g. Devise techniques for repair, protection,
or salvage of bridges damaged by internal flaws; and
h. Expand the knowledge of loading history
and life expectancy of bridges.
2. The Secretary of Transportation explore
the alternatives for action to assure mandatory application of the bridge
safety requirements of the 1968 Federal-Aid-Highway Act to all highway
bridges in the United States, since the majority of older bridges in the
country are not in the Federal-Aid-Highway System and these bridges are
most susceptible to extensive repair or replacement; including such alternative
courses of action as urging the adoption by the States of mandatory standards,
or the enactment of Federal legislation applicable to all highway bridges.
3. The Secretary of Transportation consider
the advisability of proposing a program of Federal aid to ensure the adequate
repair of all bridges not in the Federal-Aid-System.