The Arizona Department of Transportation (ADOT) recently announced it has used carbon fiber strips that are “coated and strengthened with a reinforcing polymer” to fix girders on state highway bridges in Phoenix. According to ADOT, one of those bridges is no longer listed as structurally deficient as a result.
As ADOT explains, the term “structurally deficient” doesn’t mean a bridge is unsafe to use. It means certain repair needs, including component replacement, have been identified through an inspection. Less than 2 percent of ADOT bridges are listed as structurally deficient.
“Our ADOT Bridge Group focuses on using new and innovative bridge-repair technologies that enhance safety while saving time and taxpayer dollars,” said ADOT Senior Bridge Engineer William Downes. “The reinforced fiber strips add strength to the girders and are designed to limit the amount of debris that could fall should a girder be struck again.”
Instead of traditional repair methods such as injecting epoxy to rebuild sections of the steel-reinforced concrete girders, crews used an FRP process from QuakeWrap – a member of the American Composites Manufacturers Association (ACMA) and a specialist in using composites to repair infrastructure. The repairs mark the first time ADOT has used CFRP composites to fix girders on state highway bridges.
“We think the carbon-fiber repairs are effective, can extend the lifespan of structures and can be done in much less time than other repair methods,” said ADOT State Bridge Engineer David Eberhart. “We’re likely to use it again if and when repairs are needed.”
ADOT says it invests more than $40 million each year in bridge preservation as part of a program to safeguard the state’s $20 billion investment in its transportation infrastructure. Earlier this year, ACMA and many of its member representatives, including QuakeWrap’s Dr. Mo Ehsani, lobbied for more investments in crumbling infrastructure similar to what the state of Arizona has done.