For decades, the Courtland Street Bridge stood as downtown Atlanta rose round it.
It’s been shored up many times, but the bridge is showing its age.
“When I got here in 2009, there was concrete falling off the bridge,” recalled Russ Seagren, facilities planning director for nearby Georgia State University. “The city had to come in and put netting in there to make sure the pedestrians and vehicles were protected.”
Now the bridge will be demolished and rebuilt in a matter of months, thanks to accelerated construction techniques that first gained attention in Atlanta when the I-85 bridge collapsed last year.
The Georgia Department of Transportation closed Courtland Street between Gilmer Street and Martin Luther King Jr. Drive on May 7. The department expects the $25 million reconstruction of the bridge through the Georgia State University campus to be finished by October.
The road closure will disrupt traffic for thousands of commuters and some 32,000 GSU students for up to six months. MARTA and other transit services have rerouted bus routes because of the construction.
But it could have been worse. If not for the accelerated construction, rebuilding the bridge could have taken up to two years.
“Six months is great news, compared to what we were originally told it might be,” said Seagren.
Built in the 1907, the 1,100-foot Courtland Street Bridge was originally known as the Washington Street Viaduct.
Seven campus buildings now surround the bridge – some within three-quarters of an inch. It crosses the MARTA and CSX rail lines and Decatur Street.
The bridge’s proximity to buildings and rail lines makes demolition and reconstruction tricky.
“It’s a very precise demolition,” said GDOT project manager Richard O’Hara. “We’re not just knocking it down.”
Demolition is expected to last until mid-June. Work began in January, before the bridge was closed.
Contractor C.W. Matthews has pounded support pilings more than 100 feet into the ground. And it’s already built some of the 26 columns that will support the new bridge – even as demolition continues.
That kind of scheduling is a key element of “accelerated bridge construction” – a catch-all term for a variety of processes. Normally, the bridge would have been completely demolished before construction began on the new structure.
Another factor in the accelerated schedule: quick-curing concrete, which can be 35 to 40 percent more expensive but sets in days instead of weeks.
C.W. Matthews gained experience in such techniques when it rebuilt the I-85 bridge last year. That project took just six weeks and required round-the-clock work.
The contractor isn’t working 24 hours a day for the Courtland Street project. But the experience gained on I-85 comes in handy, according to company project manager Mark Dolan.
“We knew we could do it,” Dolan said. “But once you do that (I-85), it gives you the confidence going forward.”
Accelerated bridge construction was once again in the news earlier this year, when a pedestrian bridge constructed with similar techniques collapsed at Florida International University, killing six people. The National Transportation Safety Board is still investigating the accident.
GDOT has assured the public the techniques it uses are safe. An inspection of the new stretch of I-85 last fall found no problems.
O’Hara said the construction methods used on the Courtland Street Bridge are safe.
“It’s just that we’re compressing the schedule to minimize the impact on the public,” he said.
“Accelerated construction” is a catch-all term for a variety of techniques. Here are some of the ways the Georgia Department of Transportation is speeding up construction on the Courtland Street Bridge:
- Micropile foundations: Special technology allowed workers to begin driving support pilings for the new bridge in January, long before the existing bridge was closed for demolition.
- Simultaneous construction and demolition: Contractor C.W. Matthews has already built some of the columns that will support the new bridge, though demolition will continue for another month.
- Quick-curing concrete: The special concrete costs more but sets in one to three days, instead of weeks.