The largest project the Georgia Department of Transportation has ever awarded and the first public-private partnership road project in the state, the $834 million Northwest Corridor Express Lanes project aims to improve traffic flow by adding 29.7 miles of reversible toll lanes in Cobb and Cherokee counties, north of Atlanta.
“It’s hard to build out of congestion,” says John Hancock, Northwest Corridor Project Manager for GDOT in Atlanta. “One of the things we are trying to do is give people a choice to avoid the congestion by building the express lanes.”
Along the 9-mile portion of the project on Interstate 75 from I-285 to I-575, the two reversible lanes will be built to the west of the seven or eight general-purpose lanes on each side. One express lane will be added along 7 miles of I-75 north to Hickory Grove Road, in the median of the three or four general-purpose lanes and one express lane will be added along 11 miles of I-575 north to Sixes Road, in the median between to the two general-purpose lanes in each direction.
Development hugs the edge of the interstate, precluding further expansion of general lanes due to the cost of purchasing additional right of way, Hancock explains.
“We’re utilizing every inch of right of way, and it’s very tight,” says Kevin Oswandel, Senior Project Manager for the project’s design-build-finance team Northwest Express Roadbuilders, a joint venture among Archer Western Contractors of Atlanta and Hubbard Construction Co. of Winter Park, Florida. “It’s a big project.”
GDOT began development of the Northwest Corridor project in 2001. It received an unsolicited P3 proposal in 2006 for Northwest Corridor from a different contractor. Legislation in 2009 required the GDOT to start procurement again. That led to a successful proposal to design, build and finance the project from Northwest Express Roadbuilders.
“One of the things we hoped to accomplish through this type of procurement is to get the designer and contractor on board, so we could get innovation by having them work together,” Hancock says. “Being a P3, we were able to take 29.7 miles and put it in one big project instead of trying to take on a bunch of little projects over the next 10 to 20 years. You don’t get the efficiency of doing the system as a whole.”
The reversible lanes allow for maximal traffic during rush hour and will have variable rate tolling. There are three access points, interchanges, between I-285 to I-575 and slip lanes to get on and off the express lanes north of the I-75/I-575 interchange.
“The challenge is in the design for the reversible condition,” Oswandel says. “We will have warning gates at the tolling areas to warn people they are going the wrong way. If they go through the warning gates, a resistance gate prevents access. No one will be able to go the wrong way without hitting a warning and resistance gate.”
The Construction Team
GDOT selected Northwest Express Roadbuilders in July 2013, and it began design and preconstruction activities in August of that year. Engineers from Parsons Transportation Group of Atlanta co-located in the offices with the fully integrated Archer Western and Hubbard teams, who jointly share construction responsibilities. Between the two of them, 275 hourly employees and 60 salaried staff along with subcontractors are working on the job, for a total of about 500 people on site.
The design-build method allowed construction to initially get under way on five areas needing an environmental re-evaluation rather than a more extensive environmental study, enabling a phasing in of the design and construction.
Construction started on October 6, 2014, and continues 24 hours a day. Some work takes place at night to allow for lane closures and to facilitate deliveries and movement around the project, which is about 37 percent complete and well ahead of schedule.
“Overall, the project has gone very well,” Oswandel reports. “We’ve been able to generate a lot of work in the first year.”
Northwest Express Roadbuilders works on the entire length of the project concurrently. Forty different crews – earthwork, pipe, wall, bridge and electrical crews – work simultaneously along the nearly 30 miles. The company is building numerous retaining walls and sound barriers. The project includes construction of 39 bridges, one of which is nearly 6,000 feet long, spanning across an interchange and rail line.
“A lot of stuff is going on at one time,” Hancock says. “On this one lengthy bridge, you are able to walk along and see the substructure to the superstructure and see everything at one time.”
Oswandel describes the bridge work as everything from simple spans to complicated structures. Some of the steel girders are curved.
The team has about 16 cranes on the project, including two 300-ton Liebherr hydro cranes, two of only four in the United States, Oswandel reports. They are used mostly for setting the more than 770 concrete girders. They can be moved within four hours.
“They have become an integral tool on our project,” Oswandel says. “They have created a lot of flexibility in our work.”
There are 63 wall systems, cut walls and fill walls; 100,000 feet of pipe to install; and utility relocations with 25 different companies.
“The communication effort is incredible,” Oswandel says.
In addition to this being GDOTs first P3, it is also the first project the agency had done with the developer’s construction engineering and inspection (CEI) official doing the daily inspection, rather than a GDOT CEI. GDOT hired an owner’s verification firm to do a 10 percent check, or more if needed, to verify the work is completed as specified.
Oswandel indicates he is proud that the joint venture enjoys a good partnership with GDOT and the incredible amount of collaboration that has taken place to keep the project moving forward.
Once complete, in summer of 2018, GDOT anticipates drivers using the express lanes will save 43 minutes of travel time if they drive the entire route.
“That’s a huge amount of savings,” Hancock says. “We’re happy. The progress has been outstanding.”
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