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Thu July 16, 2009 - Southeast Edition
Making a dangerous stretch of South Carolina highway safe for motorists, while giving residents and vacationers a faster way of escaping an approaching hurricane, is the goal of a $100 million road project near the state’s southernmost tip.
Eight miles (12.8 km) of the U.S. 17/ACE Basin Parkway, a stretch of the federal highway just north of Beaufort, is currently undergoing an expansion from a treacherous two-lane road to a median-divided four-lane highway (a smaller segment of the highway will even include a fifth lane).
Work began on the roadway in March 2007 and is anticipated to be completed in September 2010, according to Chris Hernandez, the South Carolina DOT’s resident engineer on the project.
This particular portion of U.S. 17 lies along a major east-west thoroughfare for trucks traveling between the ports of Charleston and Interstate 95, a distance of approximately 60 mi. (96.5 km). It is also a notoriously narrow and dangerous stretch of road that has been the scene of many deadly accidents over the years.
“This really is a safety project,” Hernandez said. “U.S. 17 is a heavily traveled road with lots of out of town traffic on it and, unfortunately, I think at one time it was declared one of the deadliest highways in the country.”
Indeed, a September 2005 study by the SCDOT found that between 1997 and 2005, a total of 983 vehicle crashes occurred on U.S. 17 between Gardens Corner and Jacksonboro, a distance of 22 mi. (35 km), with a total of 33 people killed and nearly a third of all accidents resulting in some injury.
That same study found that the fatality rate along that stretch of U.S. 17 was 77 percent higher than on the country’s interstate highway system.
In addition, Hernandez said that the road serves as a key hurricane evacuation route for many people in the coastal region. Expanding U.S. 17 from two to four lanes will effectively double the outbound traffic during storm season.
Prior to construction, that portion of the U.S. 17/ACE Basin Parkway was a two-lane ditch section with either very narrow shoulders or no shoulders at all. The road also travels through the heart of South Carolina’s Low Country, a largely marshy terrain known for its environmentally sensitive wetlands (ACE is an acronym for Ashepoo, Combahee and Edisto, the three major rivers that the road crosses).
Clearly, improvements to the road were desperately needed.
The part of U.S. 17 currently being expanded runs east from its intersection with U.S. Highway 21 at Gardens Corner to the Combahee River. Known as Segment 1, this stretch of the roadwork will cost about $80 million when it is completed next spring.
Segment 2A runs east from the Combahee to the existing four-lane roadway at Lightsey Plantation. Work is expected to be finished on it in September 2010.
When the work is completed, each lane of traffic will be 12 ft. (3.6 m) wide with 12-ft. shoulders on each side. In addition, some portions of the road also will have recoverable slopes to allow motorists who run off the road to safely correct and a 100-ft. (30.5 m) median separating each direction of traffic. The road between Gardens Corner and Big Estate Road also will have a new, 10-ft.-wide multi-purpose pathway.
Phillips & Jordan Inc., headquartered in Robbinsville, N.C., is the lead contractor on the U.S. 17 project. The firm is partnering on the design-build project with Davis & Floyd Inc., the Greenwood, S.C.-based design and engineering company.
Crews are currently laboring at several points along the road but, according to Hernandez, the work has done little to impede the traffic along U.S. 17.
“We are having really very little impact on traffic,” he reported. “We built the two new lanes first and switched traffic over to them when we began rehabilitating the old existing lanes.”
Most of the activity is going on at the interchange of U.S. 17 and U.S. 21 at Gardens Corner on the project’s far western end where an overpass is being built, Hernandez said.
Detours around the work zone are up at four different points, but as the area is so marshy, Hernandez said the detours are confined to a very tight area and do not take motorists very far from the work.
“We had to shift the U.S. 21 roadway where it intersects with U.S. 17 so traffic is creeping back and forth while we are staging our bridge construction,” he explained.
Nearby, work also is progressing on a causeway that is almost 2 mi. (3.2 km) in length, half of which is over what Hernandez calls “pure marsh.”
Wetlands, Wet Weather
Adding to the wet landscape has been an overabundance of rain so far in 2009, he said. The rain has not slowed the work too much, though, as there has been some weekend work to make up for the days lost to the weather
Due to the many wetlands all along the roadway’s length, modifications have been made to the way crews with Phillips & Jordan and its many subcontractors would normally haul in fill material to build up the roadway and shoulders.
For instance, Lane Hauling & Excavating Inc., based in Clarkrange, Tenn., has been using side-dump trailers to place the fill at a few places along the construction route. The trucks, owned by Lane, are manufactured by Side Dump Industries (SDI) in Nebraska. Unlike traditional dump trucks, SDI trailers carry the load over the suspensions of both the trailer and the tractor.
“A significant portion of the job is widening that causeway,” explained Brian Kuhnle, a P&J vice president and division manager in the company’s Greensboro, N.C., office, “and because of some very bad geotechnical issues we could not drive on the new embankment until we got about 8 feet of fill down first. So what the crews have been doing is running the side dumps down the existing road without leaving that roadway, then they can dump to the side.”
From there, Kuhnle said, crews are using long-stick excavators to distribute the material so that eventually the embankment is built up enough that they can then move conventional trucks in to dump and spread the remaining material.
Phillips & Jordan also has used a variety of track hoes made by Caterpillar, Volvo and Komatsu, said Crawford Moore, P&J’s construction manager on the project, as well as motorgraders and smooth-drum rollers by Caterpillar and traditional bulldozers made by Caterpillar and John Deere.
As the dog days of summer approach, as many as 70 people can be found working on the project on any given day. According to Hernandez, there has been some night work on the project – mostly paving and concrete work to save the crews from the excessive heat and humidity of the day. CEG
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