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In a tight spot: Alleghany County I-64 project calls for specialized excavators

Spring 2012

Rugged, winding terrain and a constricted operating area presented special challenges for the contractor in charge of installing safety and drainage improvements along a five-mile section of I-64 in Alleghany County, Virginia.

Branch Highways Inc., a full-service heavy highway and civil construction company located in Roanoke, Va., was awarded a $10.6 million contract for the project in March 2010, by the Virginia Department of Transportation (VDOT). A privately held company, Branch Highways operates under an Employee Stock Ownership Plan (ESOP) and performs a variety of work throughout the mid-Atlantic area, including commercial, residential and industrial developments, highways, airports, landfills, dams and reservoirs.

Alleghany County interstate project

The Alleghany County project extended from 2.8 miles west to 2.3 miles east of the Low Moor interchange at exit 21 on I-64. The project called for the reconstruction of the inside shoulders of the interstate as well as the installation of high-tension cable guardrail in the median. Improvements to the drainage system that lies beneath both lanes of I-64 and the adjacent frontage road were also part of the project.

Average daily traffic volume on this portion of I-64, which connects I-81 near Lexington, Va., on the east with I-77 near Beckley, W.Va., on the west, is more than 20,000 vehicles per day. The project area lies within the rugged and beautiful George Washington National Forest.

New safety measures

The mountainous terrain confined the interstate in the project area, limiting the median width to just 10 feet. According to VDOT, the project was designed to improve safety conditions along this portion of I-64 and Winterberry Avenue by protecting motorists from cross-over collisions between eastbound and westbound traffic on these routes. To this end, Branch Highways installed a total of 60,800 linear feet of high-tension cable barrier on this stretch of road.

"The project also required us to remove and replace existing storm drain pipes," says Greg Montgomery, project superintendent for Branch Highways. "Throughout the project, these pipes run perpendicular to and across the interstate and frontage roads. This required us to work in half of each roadway at a time while maintaining traffic in the other lane.

"On the frontage roads," Montgomery says, "the lane widths are very narrow, requiring the use of an excavator with a reduced tail swing to safely allow traffic to pass in the open lane."

The excavator Branch Highways picked for this task was a Doosan DX140LCR, which was rented from H&E Equipment Services, the Doosan dealer in Roanoke. The swing radius on the 14-ton DX140LCR is just 4 feet 10 inches, which allowed it to work on congested jobsites like the Alleghany County project.

At the same time, the DX140LCR offers a long 12-foot, 4-inch track length for exceptional digging and lifting capacity as well as a class-leading bucket breakout force of 23,149 pounds.

"The DX140LCR was very agile in moving around in limited-space work areas, especially during narrow roadway work under traffic," Montgomery says. "The power and smoothness of operation was very good. And the rear-view camera was useful and definitely helped the operator view the machine's surroundings."

Montgomery said drainage improvement work required 50 open-cut installations crossing all lanes of I-64. A total of 52,600 linear feet of under drain and 6,000 linear feet of storm drain pipe were installed. Most of this work was completed before the project closed down for the season.

The next spring, Branch Highways was in need of an excavator that could handle a wide variety of tasks and was capable of easily traversing the entire five miles of the project under congested traffic conditions. Their choice this time was a Doosan DX190W wheel excavator, again rented from H&E Equipment Services.

"Tasks assigned to the DX190W included grading out for asphalt patching following road-crossing pipe installations, grading the hot asphalt to minimize hand work, excavating drainage ditches, dressing hard-to-reach areas in preparation for seeding, off-loading construction materials, you name it," Montgomery says. "We also used this machine anywhere a typical excavator would be used. The DX190W performed exactly as needed — moving around easily in traffic — and was very reliable."

The DX190W features a fully hydrostatic drive with a 3-speed power shift transmission and a top travel speed of 22.4 mph. The front axle oscillates and steers but can be locked rigid for increased digging performance; the rear axle is rigid.

Work on the project culminated with a 2-inch overlay of the roadway using 32,900 tons of bituminous asphalt. Construction was completed in December 2011.

"Both of the Doosan excavators performed very well and were an exact fit for the conditions we were exposed to," Montgomery says. "I would recommend to other contractors that they try the Doosan machines, and I will certainly rent them again."