The planning and construction of the 13-mile, $262 million U.S. 29 Lynchburg/Madison Heights Bypass was a long time coming for the citizens in the south-central Virginia college town. The project was first seriously mentioned in the late 1960s; it wasn’t until 1998 that the first shovel was turned.
The project was intended to move traffic quickly and safely from Amherst County to the city of Lynchburg and to eliminate the heavily traveled, oft-congested Madison Heights area.
Literally, the planning of construction began with a ground-up approach and it started with a concept called “parallel plans.” Parallel plans can best be described as all stakeholders working together as a project team, beginning with design and carrying through construction.
At regular intervals, designers, engineers, project managers and, on occasion, area property owners and citizens would get together to take another critical look at progress, successes, concerns and lessons learned and determine the best course for moving ahead. This provided the entire team a more global perspective of the entire bypass.
“We also knew that we had to be careful building each of our structural layers, including embankment, subgrade, stabilization, asphalt and concrete,” said Don French, P.E., Virginia Department of Transportation (VDOT) Lynchburg District materials engineer. “We wanted to make sure everyone understood that one step of road preparation led to and had a serious effect upon the next. We made it clear to our contractors that citizens would see the Madison Heights Bypass as a whole, not nine separate projects or contracts, and that individual contractor efforts would go a long way to ensuring that the final product was a good one.”
This concept, while certainly not new, was presented to VDOT employees and all contractors by Dale H. Grigg Jr., P.E., Lynchburg assistant district administrator for construction.
“I became familiar with this concept of parallel plans while attending a conference. Simply put, the success of each layer of roadwork depends upon all involved. At no point should the plans intersect . . . they should simply run one on top of another,” said Grigg.
“We partnered with our contractors on every job,” Grigg continued. “Partnering allows you to share a common goal before the first shovel of dirt is turned. Then, each step along the way, everyone should know where everyone else stands on getting the job done and done correctly. If someone has a problem, the expertise of all involved is available to provide suggestions or lend a hand.”
The key benefit of this partnering was that all parties involved with the construction of the roadway and the respective pavement were on the same page, a parallel page.
Basically, development and construction of the Madison Heights Bypass came down to a simple formula: Parallel Plans + Parallel Page = Unparalleled Performance.
“I describe this as what can be achieved when everyone involved understands the goal and works cooperatively toward achieving it,” said Grigg.
In achieving that goal, VDOT has achieved its goal to provide relief to the traffic-stressed area.
Making the grade
In 1987, the U.S. 29 corridor from the city of Lynchburg to the town of Amherst had an annual average daily traffic volume of 37,000 vehicles per day with 6% tractor-trailer traffic. By 2010, the volume was expected to increase to 60,000 vehicles per day and the area had already seen an increase in the number of through tractor-trailers.
The mainline bypass was constructed of continuously reinforced concrete pavement, a technique infrequently used on road projects in this portion of the commonwealth of Virginia. The connectors and interchanges were built with a hot-mix asphalt design.
“Again, we were particularly concerned about the subgrade,” said French.
This was due in part to the micaceous nature of the soil. Because of the mica content, soil cement (12% by volume) was used to help provide stability at subgrade elevation.
“This was our first opportunity to start right and stay right on this project,” said Grigg. “A good riding concrete surface starts with the subgrade.”
The soil cement was maintained within a 1?2 in. from the plan elevation. It was then primed and sealed with an asphalt emulsion to protect and cure the layer. Following the installation of the edge drains, a 3-in. lift of Superpave BM-25 was placed on the surface.
Laying asphalt to grade proved to be challenging. The two prime contractors used systems so that the grade could be placed from a string line, but there was a learning curve that resulted in substantial areas not appropriate for construction.
“It was back to basics,” said French. “Our employees maintained a constant vigilance on the projects. We relearned or learned the string-line technique and made sure that the grade was as dead-on as possible.”
To build the continuously reinforced concrete pavement, each contractor set up a concrete production plant. The sites were very different in nature, and those differences were evident in the contractor’s ability to provide the product desired.
Perhaps the most difficult job on the project was the steel tying. For the steel design, No. 7 English or No. 22 metric longitudinal bars spaced at 6 3/4 in. (plus or minus 3/8 in.) were used. The transverse bar was No. 5 English or No. 16 metric spaced at 48 in. (plus or minus 2 in.). Crews worked from sun up to sun down at a steady rhythmic pace.
The southern end of the project used the Hardy Chair-Lok system to set the steel at mid-depth while the northern end used SMI’s combination transverse bar-and-chair assembly. Each system had its own benefits but both worked effectively.
As with many other components of construction, the prime contractors used two different systems for construction, but there was one thing each did that really made a difference.
“We had each contractor construct a test pad exactly as the pavement would be built. This helped all parties work out the bugs before the operation began,” said French.
Thinking ahead, each pad was built on a planned truck weigh station. The southern project had problems with mix temperature and paving; however, through this effort the problems never hit the mainline.
The southern project utilized a four-track paver with a side-belt feed on the placer/screed. This was very effective because crews had made a substantial effort to ensure the paver’s track area was extremely level. The paver was followed by some light hand work to strike off the surface. This was intended to knock off any mortar and to smooth any imperfections the paver may have left.
Once the surface was ready, the tining and curing compound operation followed with transverse random tining being utilized. Approximately 12 hours later, the longitudinal joint was sawn. The finished product resulted in an average Internal Roughness Index of 50 to 60.
From top to bottom, the U.S. 29 Madison Heights Bypass is a success. Already, traffic delays on U.S. 29 Business (old U.S. 29) have decreased substantially, and it appears that trade has increased in many of the businesses located along the roadway.
“Customers have rediscovered the area businesses,” said Grigg. “They no longer drive 20 miles into Lynchburg just to avoid long lines of traffic or difficulty entering and exiting businesses.”
And that was the plan.