a lot more
assured bridges delivered via ABC practices would
meet durability and seismic requirements. Now ABC
is becoming a standard practice for bridge projects
across the United States, which needs to invest
US$20.5 billion annually to eliminate the nation’s
deficient bridge backlog by 2028, according to the
U.S. Federal Highway Administration.
Most ABC projects cut construction schedules
from months to weeks, says Mr. Carrara. When his
company recently completed an ABC project in
Waitsfield, Vermont, USA, the bridge was erected in
just four weeks, with a few additional weeks needed to
finish and pave connecting roads. Without ABC, the
project could have extended much longer, he says.
But all the time savings don’t come out of
nowhere, says Fernando Quiroga, president, Quiroga
Pfeiffer Engineering Corp., Albuquerque, New Mexico, USA: “ABC projects are a lot more efficient, but
they require very careful project planning.”
New Ways of Working
During the design phase, precasters and engineers
need to work closely with project owners. The team
must ensure the design is achievable and that the
A Shorter Span
Bridge construction projects are a commuting
nightmare. There’s no easy detour around the
interminable lane closures and traffic jams they
trigger. But as U.S. state transportation departments embrace accelerated bridge construction
(ABC) practices, this type of disruption could
become less common.
ABC can dramatically compress construction
phases. Bridges are closed entirely, and prefabricated elements built off-site are assembled on-site
to speed assembly. This method reduces traffic
headaches and environmental impacts; less grid-lock means fewer auto emissions. And by enabling
projects to be completed within traditional construction seasons, ABC practices reduce the risk of
potential weather-related delays.
“You get the structure up much faster, which
makes the public and project owners a lot happier,”
says Joe Carrara, president of J.P. Carrara and Sons,
a concrete production company located in Middlebury, Vermont, USA.
As of 2016, ABC projects have been completed or
are underway in 44 of 50 U.S. states. Governments
have been slow to adopt the approach; they had to be
U.S. bridge projects have been putting the “accelerated” into ABC.
Location: Interstate 95, near Christiana,
Budget: US$4.7 million
Achievement: Working 24 hours a day,
project teams turned what would’ve been
a six-month project into one that lasted
Location: Interstate 10 Tex Wash Bridge,
Budget: US$5 million
Achievement: When parts of the bridge
collapsed during a storm, the state turned
to ABC methods to replace the structure
in two months. Otherwise it could have
taken almost 10 times as long.
Location: Bessemer Avenue Bridge, East
Budget: US$2.3 million
Achievement: A 20-person crew replaced
an 86-year-old bridge in just 57 hours—
avoiding a big headache for those in the
22,000 vehicles that traverse it every day.