Despite a lengthy delay, crews in Horry County, S.C., are making steady progress extending Carolina Bays Parkway (SC 31) from SC 544 to SC 707, just north of Moss Creek Road. A distance of roughly 4 mi. (6.4 km), the project is a new location, multi-lane freeway facility with a grassed median that will include a bridge over the Atlantic Intracoastal Waterway and interchanges at SC 544 and SC 707. The bridge is a high-level, fixed span bridge 3,632.5 ft. (1,107.2 m) in length, with a navigational clearance of 65 ft. (19.8 m).
“The original project was developed by a local grass roots committee and extended from North Carolina to the Highway 17 bypass south of Highway 544,” said Steve Gosnell, Horry County assistant county administrator. “Due to the cost of the project, as well as available funding, the project was phased with Phase 1 [Hwy 9 to Hwy 501] being built in the late 1990s, and Phase 2 [Hwy 501 to Hwy 544] being built in the mid 2000s. The current project is Phase 3 and extends the Parkway from Highway 544 to Highway 707.
“The project was needed to provide a north and south controlled access facility to improve mobility, reduce congestion on the Highway 17 bypass and accommodate the increased traffic created by a growing permanent population and the growing tourism industry along the Grand Strand. The governor-appointed RIDE Committee identified it as a top priority, as did the GSATS Committee. This third phase is the continuation of the original project scope developed by the grass roots committee.”
The site is physically located in the unincorporated area of Horry County. Horry County consists of various municipalities, which includes the city of Myrtle Beach. Work began in February, 2014.
“This particular project has had very minimal impact on traffic,” said Gosnell, “as it is mainly in an undeveloped area. However one of the bridges will span Enterprise Road, which will require it to be closed for nine months, rerouting traffic in another direction. This road has a few businesses, but is mainly residential.”
Although work is continuing without any major snags, environmental inquiries did force delays. The main concern has been environmental stewardship, due to the crossing of the Intracoastal Waterway and the associated wetlands and floodplain.
“The South Carolina Department of Transportation (SCDOT) was asked by the U.S. Army Corps of Engineers (USACE) to reassess wetland impacts from Phases I and II, with respect to the original permit application that was submitted in 2000 for the entire corridor,” Gosnell said. “This included new wetland delineations and surveys.”
For roughly two years, construction on the 31 extension was put on hold, while the SCDOT worked with the USACE on issues related to obtaining a water quality permit. The process involved a great deal of detailed field analyses and coordination with the Corps.
Elizabeth Williams, USACE project manager, explained construction on the 31 extension was on hold, while SCDOT worked with the Corps of Engineers on issues related to the water quality permit.
“The Corps processed a DA permit modification request for the Carolina Bays Parkway, which included unauthorized impacts to wetlands in the constructed portion of SC 31, as well as changing the terminus of SC 31 to SC 707,” said Williams. “This included the impacts to waters of the U.S. by the widening of SC 707.”
Field analyses involved identifying impacts to wetlands, as well as identifying the location and configuration of wetlands along SC 707. The Corps was in constant communication with SCDOT and its consultants regarding the project.
Some nearby residents and conservation groups demanded more information about the project, voicing concern about the environmental impact.
“Wetlands provide a multitude of functions, which include natural water quality improvement, flood protection, recharging groundwater, shoreline erosion control, habitat for wildlife and opportunities for recreation and aesthetic appreciation,” Williams said. The Corps’ Regulatory Program is committed to protecting the nation’s aquatic resources, while allowing reasonable development through fair, flexible and balanced permit decisions.”
As for the project’s cost, much of the SC 31 widening project is made possible by the State Infrastructure Bank, which provides funding to entities that officials say demonstrate a strong local commitment to transportation.
“Through its local option sales tax program, Horry County is providing over $300 million for improvements to state-maintained highways,” said Williams. “As a result, the bank partnered with the county to provide the bulk of the funding for the Carolina Bays Parkway Phase III project.”
The purpose of the bank is to select and assist in financing major qualified projects, exceeding $100 million, by providing loans and other financial assistance for constructing and improving highway and transportation facilities necessary for public purposes, including economic development.
“The contractor is currently working on construction of the new bridge over the Intracoastal Waterway (ICWW), and constructing the embankments for the new roadbed between Enterprise Road and SC-707, said Travis Patrick, SCDOT engineer. “Construction has been running smoothly.
“On the ICWW Bridge, the contractor has completed all of the drilled shaft foundations on the north side of the waterway, and has begun the drilled shaft foundations on the south side of the waterway. They are currently constructing the columns and caps for the new bridge on the north side of the waterway. The piles for the end bent on the north side of the waterway have been completed.”
Flatiron Constructors Inc. of Colorado is serving as the prime contractor. Crews used conventional clearing for most of the new alignment. However, in the wetlands areas, most of the vegetation was mulched in-place to avoid disturbing the existing ground and root mass. This effort will maintain the ground profile at the same level it was prior to construction, and allow vegetation to reestablish itself much quicker once the project is complete.
“For the site prep of the roadbed, the organic layer of material was stripped off and much of it was stockpiled for later use as topsoil material,” Patrick said. “A soil bridge lift was used to provide a stable working platform for the construction equipment. The borrow material was brought to the site in on-road dump trucks and unloaded at a transfer station, where it was reloaded into off-road dump trucks for transport along the new road corridor to the working area. This was done to minimize wear and tear on the on-road trucks and avoid trucks getting stuck in loose patches of sand disturbed by the construction traffic.
“The amount of borrow excavation material that will be brought in from off site is estimated to be almost 1 million cubic yards. The amount of onsite material that will be excavated and relocated is estimated to be approximately 260,000 cubic yards.”
There are five bridges on the project, including the main bridge over the ICWW, two small bridges over wetland areas on the SC-31 mainline, a bridge over SC-707 for the new interchange and a new bridge on Enterprise Road that will span over SC-31, according to Patrick.
“The ICWW Bridge has six lanes, each 12 feet wide, with 10 foot interior and exterior shoulders for both northbound and southbound lanes,” Patrick said. “The main clear span over the ICWW is 310 feet long. The end bents are supported on HP pile foundations. Interior bents are drilled shaft foundations. There are 92 to 84 inch diameter drilled shafts and 16 to 102 inch diameter drilled shafts.
“The Enterprise Road Bridge spans 223 by 37 feet wide. It has two lanes, each 11 feet wide, with 5 foot shoulders, and is supported on HP piles on the end bents, and two 72 inch diameter drilled shafts on the center bent.”
The SC-707 Bridge spans 148 by 86 ft. (45.1 by 26.2 m) wide. It has three lanes; each 12 ft. (3.7 m) wide, with 10 ft. (3 m) interior and exterior shoulders for both northbound and southbound lanes and is supported on HP pile foundations. The First Dual and Second Dual Wetland work involves two bridges side by side. One spans 60 by 63 ft. (19.2 by 19.2 m) wide, the other 60 by 51 ft. (18.2 by 15.5 m) wide. They are supported on HP and concrete pile foundations.
There are still more than two years left in the project. Estimated time frames to finish some of the major items include the completion of the ICWW Bridge by the end of 2016, the Enterprise Road Bridge by late 2015 to mid 2016, two wetland bridges by 2015, the SC-707 Bridge by mid 2015 to mid 2016, concrete paving by mid 2015 to late 2016 and asphalt paving sometime between 2016 to 2017.
“One of the main challenges for this project has been the work through, and in proximity to, the ICWW and the wetlands areas,” Patrick said. “Prior to any work starting, the clearing limits for the project had to be surveyed in, and a barrier and warning fence installed to prevent equipment from entering a non-permitted area. Wetland areas near the ICWW were permitted to be cleared, but could not be grubbed, and no fill could be placed. Flatiron has built a temporary trestle alongside the new bridge that is being used for access of construction equipment while building the new ICWW Bridge. This minimizes the disturbance of the ground during construction.”
Currently there is no shift work or night work, but some night work will be required when lanes are closed on some of the major routes, such as SC-707. Flatiron Constructors has approximately 50 personnel on site at this time. The subcontractors have approximately another 30 on site.
“Since this project is mostly on a new alignment, there are minimal impacts to traffic,” said Patrick. “The closure of Enterprise Road for nine months will impact motorists, since they will have to use a detour route to get to a designated evacuation route. The contractor is required to have a plan in place before the beginning of each hurricane season with the measures they will take to protect the traveling public in the event of a hurricane, as well as the measures they will take to protect or stabilize equipment and partially completed structures.”
Equipment on the project includes cranes, a crane mounted drilled shaft rig, on-road dump trucks, off-road dump trucks, bulldozers, trackhoes, backhoes, loaders, material handlers, manlifts, concrete pump trucks and concrete trucks. Some of the main materials being used on the project include 1 million cu. yds. (764,554.9 cu m) of borrow excavation, 260,000 cu. yds. (198,784.2 cu m) of unclassified excavation, 265,000 sq. yds. (221,573 sq m) of 6 in. (15.2 cm) graded aggregate base, 150,000 sq. yds. (125,419.1 sq m) of 9 in. (22.9 cm) concrete pavement, 90,000 sq. yds. (75,251.5 sq m) of 9 in. concrete shoulders, 8.3 million lbs. (3.76 million kg) of reinforcing steel and 30,300 cu. yds. (23,166 cu m) of Class 4000 concrete.
The project has reportedly been running smoothly with only minor issues. Weather has not been a major factor, to date. There have been some periods of wet weather, but the contractor has been able to continue working in areas that are less impacted by showers.
The total project, including preliminary engineering, right-of-way acquisition and construction is estimated to cost approximately $200 million and is funded by the State Infrastructure Bank, American Recovery and Investment Act Funds and earmark funds.
Horry County, in partnership with the SCDOT and the Federal Highway Administration (FHWA), is working to complete the Carolina Bays Parkway to improve mobility and connectivity on the Grand Strand’s existing transportation network. SCDOT will manage the day-to-day operations of the project.
If all goes according to schedule, the completion of Phase III is expected by spring 2017.
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