An aerial view of the barge in Lake Lanier as work began. (GDOT photo)
In northeast Georgia, crews are building the new State Route 284 Bridge over a portion of Lake Lanier.
The $8.7 million project involves building the structure over the Chattahoochee River portion of Lake Lanier at the Lake Lanier Olympic Center. The new bridge will have 12-ft. (3.6 m) wide lanes and an 8-ft. (2.4 m) wide bikeable shoulder in each direction. It includes a new pedestrian tunnel under SR 284.
“There are some interesting and unusual aspects to this project,” said Georgia Department of Transportation (GDOT) Communications Officer Teri Pope. “The project is on an Olympic venue. The canoe and kayak events were held there in 1996, and the course is still used for world-class competitions. A pedestrian tunnel under SR 284 is part of the project, so athletes and fans don’t have to cross the state route to access the viewing stands or the start line. Currently, athletes carry their long canoes and kayaks across the state route, stopping vehicular traffic.”
Named for famed poet Sidney Lanier, the lake was built and is operated by the U.S. Army Corps of Engineers. It is patrolled by the Georgia Department of Natural Resources.
According to GDOT Project Manager Brandon Kirby, crews have recently been busy pouring in place the concrete for the tunnel. It then will take at least 30 days for the concrete to cure to the strength needed to support the roadway and traffic.
“About half the time of the detour is for concrete to cure,” Kirby said. “Then, the grade of the roadway over the tunnel will be set, the roadway paved and sidewalks built.”
Bridge work has involved pouring caps in the lake. Two will be on land. Crews have begun driving steel H-shaped pile for the footings on land that will support the new bridge. Steel H pile is driven down to a maximum depth of 56 ft. (17 m), which is considered an extremely noisy operation. Driving pile will take about a week — 18 piles to be driven, nine on each end of the bridge. Workers expect to start setting the bridge beams in early July, weather permitting.
In addition to drilling and pouring and curing caissons and caps in Lake Lanier, the project has required clearing and grading. Some of the other tasks involve driving pile for the footings on land, pouring the bridge deck, grooving and striping, along with guardrail and signage installation. Once traffic is shifted to the new bridge structure, the original bridge will be demolished.
“There are 12 caissons on this project,” said Kirby. “Eight of them are five-and-a-half feet in diameter, and four are six-and-a-half feet in diameter. The largest four caissons have cooling tubes inserted into the concrete, running the full length of the caisson to cool the concrete.
“As concrete hardens, it puts off heat — heat of hydration — so, by cooling the concrete and slowing down the curing process, we get stronger concrete. The caissons are drilled down to bedrock, depth ranged between 95 and 107 feet deep. The last caisson was poured May 30, 2014.”
The grade of SR 284 must be raised by 3 ft. (.9 m) to accommodate the new concrete tunnel, which is 10 ft. (3 m) wide, 8 ft. (2.4 m) high and 63.12 ft. (19.2 m) long. Traffic cannot continue to flow in, as crews change the grade of the roadway and build the pedestrian tunnel.
As part of the project, workers had to remove the existing asphalt and excavate to the depth of the concrete culvert that will be the pedestrian tunnel. Once curing is complete, the road grade can be set, along with paving over the tunnel. After that, the road will be reopened to traffic. The contract states the road must be open by the final week of July, some 60 days after closure.
As for special concerns when dealing with water-related projects, athletic events held inside the project on the lake have special work-hour restrictions. People come from around the world to compete and watch.
According to Pope, “The GDOT did lots of outreach using traditional media, social media, the Hall County Parks and Recreation Department, along with the Canoe Kayak and Rowing Clubs. We also held a community information session to tell the community about the detour and share details. The detour was planned so that school buses would not be involved.”
The summer detour to close SR 284/Clarks Bridge Road began in late May. Signs announcing the detour are in place along the roadway. No through traffic will be allowed on State Route 284/Clarks Bridge Road at the Lake Lanier Olympic Venue in Gainesville through July 26, 2014.
“SR 284 southbound cannot access the parking or boat ramps for the canoe, kayak venue and swim area,” Pope said. “Traffic on SR 284 northbound can still access these areas, so motorists just have to approach their destination from the correct direction. The biggest impact has been to signal timings along the detour route. The increased traffic created longer than normal wait times trying to access SR 11/US 129. GDOT Engineers have adjusted the signal timings and traffic is flowing better along the detour route.”
Lane closures will continue through the rest of the project. As far as waterway work restrictions, the contractor will maintain two-way boat traffic on Lake Lanier through the project area at all times, with a minimum of 30 ft. (9.1 m) per lane required. The Corps of Engineers set up buoys delineating the boat pathway. The contractor cannot block the boat ramp area parking or launch area except, for areas being changed or rebuilt during construction.
The detour of SR 284 for construction of the pedestrian culvert/tunnel construction must occur during the summer holiday for the Hall County School System. Vehicles cannot cross SR 284 in front of the Lane Lanier Olympic Center building as the tunnel is being built. The signed detour route directs traffic north on U.S.129/Cleveland Highway to Ga. 284 in Clermont and then directed south toward the bridge.
The project was awarded to E. R. Snell Contractor Inc., of Snellville, Ga. According to E.R. Snell Vice President and Project Manager Randy Griffin, “The main equipment for bridge construction are two Link-Belt 218 110-ton cranes, one Link-Belt 248 200-ton crane, excavators, caisson drilling machine, dozers, motorgraders and barges. The main materials include concrete, rebar, pre-stressed concrete beams and drilled caissons.
“The biggest challenge was getting the caissons, or drilled shafts, out of the water,” Griffin said. “We had to use the new GDOT mass concrete spec, deep water drilling, and so forth.”
The original bridge has run its course. It opened to traffic in 1958, as the construction of Lake Lanier was finished. The bridge deck is rough with spalling and cracking due to a failed epoxy coating. The bridge also has attached water and telephone lines, as almost all bridges in Georgia carry utilities.
The existing bridge, which fails to meet current design standards, is 834 ft. (254 m) long by 23.8 ft. (7.2 m) wide, without shoulders, and nine piers in the water. The new bridge will be 40 ft. (12.2 m) wide. It will be the same elevation as the former bridge and is being built east of the original structure, with a caisson depth from 92 ft. (28 m) to 105 ft. (32 m).
Lake Lanier is the largest man-made lake east of the Mississippi River. Average daily traffic on the bridge in 2012 — the latest year calculated — was 8,130. The lake’s popularity is partly due to its proximity to metropolitan Atlanta. Lake Lanier consists of over 690 mi. of shoreline and more than 100 small islands. It’s famous for fishing and sailing. Water skiing and jet skiing also are popular activities.
Lake Lanier has been described as one of the nation’s favorite lakes and is reportedly the most visited Corp of Engineers project in the United States. The Corps manages the shoreline of Lake Lanier to preserve and protect the lake’s environment. It operates almost four dozen parks around the lake for boat launchings, hiking, swimming and other activities. There are a dozen campgrounds around the lake, as well as six major golf clubs. Most of the surrounding land, however, is either owned privately or by the Corps, resulting in few walking trails.
The project should be almost 50 percent complete by the end of July.
Although heat hasn’t been much of a factor, crews have had to deal with rain. To date, however, there have been no significant setbacks due to wet weather.
This is the first bridge over Lake Lanier to be replaced. The expected completion date is Dec. 31, 2015.