- The bridge is 2,500 feet long and about 85-feet above SR 400
- Its construction had challenges such as the seismic design criteria that the engineers followed
- “We have been able to count on all of them to keep the job running, and that is another example of the commitment that we as a team have with this project” says Alba Corrales, Sr. Project Manager for North Perimeter Contractors, LLC
Since the Summer of 2019, structures crews have been busily working on the critical path for the Transform 285/400 Project. The biggest component of the critical path is Bridge 21. The bridge is approximately 2,500 feet long and about 85-feet above SR 400. It will allow motorists to travel from SR 400 southbound south of Hammond Drive to I-285 eastbound ending just east of Peachtree Dunwoody Road. Bridge 21 will replace the outdated clover-leaf system to meet the traffic demands in Atlanta.
Crews worked day, night, and sacrificed a long holiday weekend to set the last set of beams for Bridge 21.
When Bridge 21 opens to traffic, the former ramp from SR 400 southbound to I-285 eastbound will close and more construction work will open. Crews can begin work on the collector-distributor lanes for I-285 eastbound to Ashford Dunwoody Road. Crews will be able to complete the construction of the I-285 eastbound ramp to SR 400 northbound and the I-285 westbound ramp to SR 400 southbound. These works will prepare for the next big traffic shift on the new alignment from SR 400 southbound to I-285 westbound.
The bridge construction has met its set of challenges and accomplishments. One challenge was the seismic design criteria that the engineers had to follow. The footings, columns and caps had rebar cages that weighed almost twice as much as previous projects that crews had worked on which meant that crews had to upsize everything including from the cranes to lift these cages. The increased amount of rebar meant that every element was much more congested inside the forms, causing the rebar to be cut and bent almost perfectly by the fabricator.
One of the greatest accomplishments has been constructing Bridge 21 in an interchange that has an average of half-million cars a day with minimum impact to the traveling public. Bent 8 of Bridge 21 is also quite unique. This bent has a posttensioned column of over 80 feet and a posttensioned cantilever cap that is holding steel beams that are over 200 feet long and over 400,000 pounds.
With the onset of COVID-19 pandemic the construction crews banded together to overcome them.
“Our team has a relentless drive to achieve more and I am grateful to be a part of this group of men and women.”
“We have been able to count on all of them to keep the job running, and that is another example of the commitment that we as a team have with this project. They are all excellent professionals and without them I have no doubt that all this that you see it wouldn’t have been possible.”
Now that the final beams are placed, the Transform 285/400 project is closer to reaching a major milestone of opening the bridge to traffic this summer.
https://vimeo.com/user117606767/download/432259497/f47c15ac8f
