FHWA Workshops Heat Up Bridge Repair Process |
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Federal Highway Administration
November 1, 1999
FOR IMMEDIATE RELEASE
Monday, November 1, 1999
Contact: Karen Whitney
FHWA 71-99
Tel.: 202-366-0660
OWATONNA, Minn.—Deputy Federal Highway Administrator Gloria Jeff today joined the Minnesota Department of Transportation in hosting a workshop to promote heat straightening, a unique approach to steel bridge repair.
The workshop is one of a series of sessions developed by the Federal Highway Administration (FHWA) to promote the state of the art in heat straightening, a highly effective, economical process that cuts repair time down to as little as several days or weeks instead of several months.
"Safety is our number one priority, followed closely by mobility – and this process accomplishes both," Jeff said. "Equipping engineers to perform this time and cost-saving technique benefits everyone, from the state and local agencies that maintain our bridges to the travelers and commuters who will face shorter lane closures and less traffic delay with this improved process."
There are nearly 200,000 steel highway and railroad bridges in the U.S. Each year many of these, due to their location or low vertical clearance, regularly experience damage from vehicles striking them from below, heavy loading on the bridge deck, vehicle fires or a variety of other factors.
Heat straightening of a damaged steel beam or girder can be done quickly on site by heating and reworking the beam in place to restore it to its load carrying capacity. This eliminates the need to remove, reconstruct or replace the damaged segments and allows repairs to be completed in a fraction of the time required for existing techniques. It also requires a minimum of materials and supplies, which keeps overall costs down.
Normally, when damage occurs, entire bridge segments are removed and repaired or an entirely new beam may need to be constructed, resulting in lane closures and construction activity that can tie up traffic for months.
The heat straightening technique has been in use for almost half a century, but the skill remained in the hands of a few craftsmen, making the technique expensive and greatly limiting its availability. Prior to FHWA’s training sessions, engineers supervising such repairs had little guidance on proper procedures for specific damage configurations or how to avoid problems such as overheating and improper application of force.
Although the technique is highly effective, if performed incorrectly, fractures and permanent weakening of the repaired structure can result, one of the main reasons many State DOT’s have not used the technique. Recent research, however, provides information on the effect of various variables which can influence the effectiveness of the heat straightening operation. Criteria now exist which will allow heat straightening to be safely and economically applied to a wide variety of damaged steel configurations.
FHWA developed the workshops and lab demonstrations to help engineers at state and local highway agencies learn to properly conduct, inspect and supervise heat straightening repairs. The Owatonna session was held at the request of Minnesota Department of Transportation engineers.
The sessions, which feature two interactive CD ROMs, instructional videotapes, case studies, and the first comprehensive manual on the technique, have garnered the support of the steel and steel bridge industries, including the National Steel Bridge Alliance. The training has also attracted the attention of engineers in the international community, including the United Kingdom which sent a representative to the training earlier this year.