Bridge work in Williamson County, Tenn., is part of section four of the project.
Usually, the motoring public, tired of delays and detours, is anxious for disruptive road construction projects to be completed. But on the SR 840 project around Nashville, Tenn., it’s hard to imagine any motorist as eager to see the end as the Tennessee Department of Transportation (TDOT) and the contractors working on the project.
It’s been a long time coming. Planning for the project began back in 1986, as part of the state’s Better Roads Program to provide economic growth by improving access to communities in central Tennessee. However, work came to a halt in 2003 due to environmental issues and didn’t resume for several years.
When completed, this brand new four-lane roadway will loop around Nashville to the south, linking I-40 between Dickson and Lebanon, with connections to Interstates 65 and 24. The 78-mi. city bypass is intended to alleviate congestion due to growth in the area and should spur economic development. As Kelly Garrett, TDOT project manager, explained, “This is much further out than the 440 loop just outside the city.”
Of the 78 mi. encompassed by this new route, 60 mi. are currently open to traffic, with approximately 18 mi. remaining under construction in Williamson County. Work on the portion of SR 840 from SR 100 to SR 46 (Pinewood Road) began in July 2007, while the other project, which stretches from Leipers Creek Road to State Route 6 (US 31/Columbia Pike), began in early 2009. The contract for the final portion was awarded in February 2010.
Completely state-funded, the project uses no federal funds.
“That’s why it’s taking so long,” Garrett said.
But other issues also have slowed work on the project.
One, Two, Three, Four
The goal is for the entire route to be completed and open to traffic by December 2012. However, as Tim Crunk, construction manager with Nashville-based Gresham Smith and Partners, explained, this project was divided into four sections, awarded in three contracts, each with separate time lines and bonuses for early completion.
The contract for sections one and two from Leipers Creek Road to Columbia Pike (SR 6) was let to bid in December 2008. Bell & Associates LP is the prime, with a winning bid of $87,360,841.47.
Steve Stewart, construction manager with Gresham Smith and Partners, said work on this 8-mi. (12.8 km) portion is 39 percent complete and includes grading, drainage and construction of bridges and retaining walls. Running the numbers, he counted 24 bridges, 22 box culverts and box bridges, 15,850 ft. (4,831 m) of storm drain, 6,000 lineal ft. (1,828 m) of new stream location (5,000 ft. [1,524 m] of which is complete), 1500 ft. (457 m) of water line (90 percent of which is complete), 34,000 trees and shrubs to be planted and 6 million cu. yds. (4,587, 329 cu m) of dirt – including 600,000 of borrow and the rest relocated from onsite. Additional work includes replacing gas lines and relocating TVA transmission lines. The estimated completion date is Dec. 31, 2011.
“To speed the process,” Crunk added, “the state included a $3 million ’no-excuse’ bonus for early completion.”
The paving contract is expected to be let in late 2011.
The contract for Section 4 from Highway 100 to Pinewood Road (SR 46) was let to bid in July 2007. Highways Inc. is the prime, with a bid of $44,215,290.68. The work entails grading for 6.1 mi. (9.8 km) of new construction, drainage and construction of 10 bridges and retaining walls. It will require 2.7 million cu. yds. (2 million cu m) of road and drainage excavation. Current schedules indicate this section could be open to traffic by the end of 2010. Excluding the paving, work is 93 percent complete with 79 percent of the time lapsed. As Stewart confirmed, work is on schedule, with an expected completion date of Dec. 31, 2010, and a $2 million no-excuse bonus for early completion. The paving contract for this section was let in February 2010 and won by Eubank Asphalt Paving & Sealing of Charlotte, Tenn., for $55.1 million.
The contract for Section 3 from Pinewood Road (SR 46) to Leipers Creek Road was let to bid in February 2010. Work recently started and includes grading, drainage, construction of 10 bridges and retaining walls and the paving. This 3.4-mi. (5.4 km) stretch will require 2.6 million cu. yds. (1.9 cu m) of road and drainage. Stewart estimated that the project is two percent complete and that three percent of the time has lapsed, with an expected completion date of Oct. 31, 2012, and $2.5 million on the line for early completion. The paving contract is expected to be let in late 2011. There are additional milestone paving bonuses for sections 3 and 4.
When Section 4 was originally let to bid in 2000, Garrett said they didn’t expend “a lot of effort to protect the environment.” The situation became so grave, it led to a lawsuit that halted the job under another contractor. Over the next two to three years, TDOT was forced to execute a redesign on all the sections. They changed culverts to bridges and incorporated other measures to incorporate erosion control. The design of the road changed so much, TDOT had to cancel the contract and re-let it.
The new route has a large footprint that includes a 70-ft. (21.3 m) median, so TDOT had to acquire considerable land in Williamson County. Fortunately, much of the new roadway cuts through farmland and undeveloped land, so little relocation of residents or businesses was necessary. Garret said that traffic counts didn’t warrant acquiring enough right of way for future expansion of the four-lane loop.
Budget also might have played a part in that decision. Plans to construct a northern loop of SR 840 north of Nashville were put on hold when the Tennessee General Assembly ordered TDOT to discontinue further studies and planning because of state budget problems and the high cost of major highway construction in that area. An entire circular loop would be about 178 mi. (286 km) long and require extensive and costly amounts of excavation, soil relocation and bridge construction due to the hilly terrain north of the city. In October 2003, the Department of Transportation placed the northern loop project into an indefinite hold situation, citing a lack of documented transportation needs.
The transportation and economic needs south of Nashville warrant the expense. In fact, Tennessee Gov. Phil Bredesen considered the completion of the southern portion of SR 840 a milestone and expects it to increase economic growth in the area as well as provide a convenient alternate route around the city and improve access to communities.
Pleasing the local communities was an important aspect of the project. A Citizens Resource Team comprised of concerned citizens and property owners was formed to study and make recommendations for the design concept for the three final sections of SR 840. The team assisted in the selection of the alignment of the road, bridge design and aesthetic features. Their recommendations were accepted by Commissioner Gerald Nicely for consideration, who said that the new roadway “serves an important transportation purpose while being responsive to community concerns.”
TDOT also worked with the Tennessee Department of Environment and Conservation, utilizing the Context Sensitive Solutions approach. The remaining projects are being constructed under stringent guidelines designed to protect the environment. The SR 840 projects have been the driving force behind monumental changes in the way TDOT handles large construction projects across the state.
“We now take extreme measures to protect the environment,” Garrett stated.
One of the main issues TDOT faces in environmental protection is erosion control. The area features hills, valleys and Tier 2 streams.
“There’s a lot of water,” Garrett acknowledged.
Because they must keep the water clean, work is monitored by the USGS for turbidity and temperature and each contractor has Erosion Prevention Sediment Control supervisors and a dedicated crew.
While much of the area consists of a mixture of dirt and clay, many parts of sections one and two are made up of Chattanooga shale. Chattanooga shale, deposited at the end of the Devonian Period, is found across much of central and eastern United States. It is the source rock for the naturally occurring oil and gas fields in Tennessee, and in some areas, oil is drilled from it. Due to its uranium content, Chattanooga Shale is regarded as a “low-grade vast reserves” source for nuclear fuel; because of its carbon content, the shale has sometimes been burned for a heat source.
However, it also can produce adverse effects on the environment. Chattanooga Shale contains a significant amount of pyrite; as it erodes, it releases sulfur into streams, increasing acidity. Therefore, stated Garrett, when it’s encountered in a cut, crews have to encapsulate the area because, if disturbed and exposed to water, it produces acid.
“We load it in dump trucks and haul it to a designated area,” Stewart elaborated. “There, in a method similar to that used at a landfill, it is placed under five feet of limestone to neutralize the acids, a geo membrane, two feet of pea gravel, two feet of clay and another geo membrane. It’s then sealed with clay. Water shouldn’t penetrate it.”
So far, Stewart estimated they’ve moved about 100,000 cu. yds. (76,455 cu m) of the shale.
“We’ve encapsulated more than we thought we would, based on the surveys and test-drills performed by the geotechnical people.”
Watching the Clock
Additional amounts of Chattanooga shale to be moved add to the already hectic schedule. Crews are working six days a week — seven days a week on grading. Stewart explained, “It was wet last year, so they’re trying to catch up.”
The ability to catch up is hampered by environmental restrictions and grading limitations, which dictate that only a certain amount of the area can be disturbed at a time.
“We got a consent order from court,” he continued, “that allows only 25 acres of disturbed area at a time over the length of the project.”
To increase that amount, crews can stabilize it and they are allowed to go above that amount if there are multiple sections under construction.
But even with those allowances, there’s a grading plan to follow, which designates certain areas where they can work at any given time, and seasonal limitations that prohibit grading from December to March because the ground is too wet and frozen.
“They relaxed the restriction on [sections] one and two,” Garrett interjected, noting that crews were permitted to work in December last year and that this year they worked in March in five areas.
Because this is new road construction, for the most part, crews are not working near traffic. Road closures, detours and lane shifting are not a factor affecting the schedule. However, as Stewart pointed out, there are a lot of side streets that interface with the route and he mentioned traffic detours on Section 4. Nevertheless, they cause minimal impact to the schedule.
Another, more common, time constraint is weather. Garrett noted that 2009 was a wet year.
“It’s been difficult to catch up. We hope for a normal — or dry — year so we can move more dirt and get back on track.”
They’re “gearing up on sections one and two,” Stewart said, with about 180 to 185 employees and 112 pieces of equipment currently on site. At peak last summer, there were 278 employees and 212 pieces of equipment on site. Some of the equipment used includes cranes for bridge work, Bobcats for moving sod, dump trucks, Gradalls and 30 individual haulers to move dirt.
“We’re cutting and hauling it to other areas onsite.”
It’s a stressful situation, Garrett said.
“A lot of eyes are watching us: residents, government offices, the media…”
There are weekly progress meetings and many inspections scheduled at various intervals to evaluate progress and performance.
Stewart pointed out that all the contractors who bid on the project were aware of the restrictions and the pressures involved. Garrett said everyone on the project is working as a team and that they “take a lot of pride in proving we can build this under the restraints.”
It’s been a learning experience in many ways. The SR 840 project has been the driving force behind monumental changes in the way TDOT handles large construction projects across the state.
“A big issue when the new administration took over in 2002 was to make TDOT more user-friendly,” Garrett said. “They wanted to get the public more involved.”
First with the citizen resource teams during the planning stages and now with the onsite SR 840 Community Outreach Center and Project Office open to the public, TDOT is embracing the administration’s mission.
“We hope these measures are changing how people view TDOT,” Garrett said, adding that she has noticed marked improvement. TDOT Commissioner Gerald Nicely echoed her sentiments when he said, “We are pleased to be moving forward with the final section of State Route 840, a project which vividly demonstrates the improvements TDOT has made in the way the department does business.”
As they battle the clock, the weather and the Chattanooga shale, everyone on the project looks forward to the day they can look back at this ground-breaking project and proudly claim responsibility for its success. They’re also looking forward to cashing in on those bonus checks. If things continue as they’re going now, it’s just a matter of time.
“Work is going real well,” Stewart summed up.