Page 129 - Bridge and Highway Structure Rehabilitation and Repair

104 SECTION 1 ADMINISTRATIVE ISSUES

The sudden reduction in the load carrying capacity of a member may occur due to post
buckling and subsequent inelastic cyclic member behavior.
If a truss with redundant members is subjected toa slight quasi-static overload such that the
failure is initiated by buckling of a member, post buckling and subsequent cycles of inelastic
force-deformation behavior of truss members may create adverse member force redistribution
that leads tocomplete collapse of the structure.

3.12.2 Suggested Preventive Action against Failure from Bomb Blast
1. Load combinations in AASHTO code should be clearly defined, and a suitable method of

analysis should be adopted.
2. Attention should be paid to multi-hazard design procedures to maintain neededsafety
levels.
3. Life cycle costs should be included for making appropriate retrofi t decisions.
4. Improving security at bridges by surveillance cameras, preventing parking in the vicinity of
bridges, installing fire controlling devices near bridge parapets, and more vigilant policing

are required.
3.13 FIRE DAMAGE TO SUPERSTRUCTURES AND PREVENTIVE ACTION
3.13.1 Vehicular Accidents
Overturning of trucks due to slippery decks may cause spraying of the deck with gasoline
and fire. Also, vehicular accidents can be the cause of fi re.

Table 3.10 shows historic details of bridge failures due to fi re.
3.13.2 Repairing the Fire Damaged Notre Dame Bridge

OnApril 12, 2003 a fireignited underneath an important bridge in the City of Manchester,

New Hampshire. Although the fire was intentionally set and causedmajor interruptions to traf-

fic, telephone lines and some city firedepartment communications, there is no evidence that this
was anact of terrorism. Althoughthere are emergency plans in place and precautions to prevent
additional threats, disasters (natural and man-made) arestill going to occur.
Table 3.10 Bridge failures due to fi re (accidental spill of oil or vandalism).
U.S. Bridges Location Year Details of Failure

Two U-section bridges South of Le Mars, Iowa 1941 Fire due to collision of two vehicles
(Floyd River)

Notre Dame Bridge Manchester, 2003 Arson
New Hampshire
I-95 bridge Northeast of Philadelphia, 2004 Fire started due to accidental burning of used tires
Pennsylvania dumped under the bridge piers
Wooden bridge spanning Rio Pico Rivera, California 2005 Fire began in combustibles beneath the bridge and spread
Hondo fl ood control channel to wooden infrastructure—Arson
British Bridges

Tubular Britannia Bridge Menai Straits, Whales 1970 Timber roof impregnated with tar paints helped fi re, steel
box girder superstructure defl ections of up to 0.75 m
Flyover over A406, Staples Corner London, England 1992 IRA bomb exploded underneath, causing serious damage
to roads and nearby buildings—vandalism