Increased traffic of approximatgely 3,000 vehicles each day spurred a $23.7-million project, creating a more direct route around the southeast section of Rapid City, SD, a booming city on the western edge of the state and a popular tourist attraction with Mount Rushmore located just west along Highway 44.
The new four-lane, 5.8-mi. connector route considerably reduces in-town truck traffic by linking Rapid Valley on the east edge of the city, to Highway 79 on the southern end, forming a bypass from Interstate 90 to Sheridan Lake Road.
“The new route is quite a bit faster than the previous alternative,” said Steve Schelske, project coordinator with SD/DOT. “The previous route came through town on Campbell Street, to Highway 79, or traffic had to use St. Patrick Street to Highway 44, and then on to Interstate 90.”
Campbell and St. Patrick streets are state highways that run through town; diverting the traffic also will improve safety in town by lessening traffic.
The project was completed in two phases: the first, beginning in 2002 at a cost of $13.3 million, included grading and surfacing of the west side of Highway 79 from Highway 44 south to Rapid Creek, completion of two ramps of a new interchange over the railroad at the north end of the project, and completion of an intersection at County Road 217.
The second phase, which was pushed back one year due to a lack of funds, was completed during the 2004 and 2005 construction seasons.
The contract amount for Phase two of the Department of Transportation work is $22.4 million.
The remaining $1.3 million is a separate contract within the city of Rapid City for work on utilities, storm sewer and water; the majority of which was completed in 2004.
Infrastructure was updated and services were provided to areas that previously did not have services, Schelske said.
The new section of highway, Highway 235 (Elk Vale Road), runs from Interstate 90, east of Rapid City, to Highway 79, south of town.
The second phase of construction included:
• Finishing a new four-lane concrete road connecting Interstate 90 to Highway 79.
• Constructing the new roadway from Highway 44 to Highway 79.
• Constructing an urban interchange at the intersection of the Southeast Connector and Highway 79.
• Constructing a bridge over the railroad tracks just east of Highway 79.
• Reconstruction of the bridge over the railroad tracks near exit 61.
• Reconstructing Highway 79 into a concrete four-lane with concrete median from Minnesota Street to 1.4 mi. south.
• Relocating County Route 217 (Old Folsom Road). Connection to Highway 79 will be opposite the Rapid City Landfill entrance.
• Adding the new Concourse Drive to tie Elk Vale to Twilight Drive.
The new highway passes over the top of Dakota and Minnesota streets, and the Eastern Railroad line and Highway 79 on two bridges.
To make the span, moe than 800,000 cu. yd. of soil were hauled in to raise the new roads, Schelske explained.
The entire project required approximately 2 million cu. yd. of soil movement.
The Highway 79 intersection was designed as an urban interchange, where traffic on the main road, Highway 79, is allowed to flow uninterrupted through the intersection.
Interstate-style ramps are used to enter or exit the highway.
Traffic on the intersecting road, the Southeast Connector Route, is controlled by stoplights on top of the bridge at the entrance and exit ramps, as well as eastbound and westbound through traffic, Schelske added.
Concrete was chosen as a surface medium because of its ability to withstand the area’s colder climate and the materials to make the product (gravel) are readily available, explained Tom Stalley, project manager with prime contractor, Heavy Constructors Inc., of Rapid City, SD.
Any asphalt that was removed to connect existing roads to the new highway was incorporated into the base course of the highway.
The concrete was placed using a concrete spreader, which is a relatively new technique for the area, Stalley explained.
SD/DOT now requires using a concrete spreader, which is a more efficient way to distribute the concrete.
Once the learning curve was mastered, dumping concrete into the spreader took less than a minute and increased productivity, he added, but because the baskets have to be setup and later washed, the cost of this portion of the project remains about the same.
“The second phase ended Nov. 16, 2005, but a couple of items remain to be finished in 2006,” Schelske said. “A city street is yet to be paved; the contractor was a little behind … Some people say the project is not done but, when put in perspective dollar wise, it is 97.25 percent complete. June was a very wet month so the project fell behind.”
Demolition of the bridge over SD Highway 44 that linked St. Patrick Street to Elk Vale Road, was demolished in early December 2005, Schelske added. The bridge is no longer needed because the new Southeast Connector bridge now handles all the traffic in that area.
Additional work is being planned by SD/DOT to make the new connector route even more efficient
Schelske explained that for 2007, DOT plans to rebuild Exit 61 over Interstate 90 into an urban interchange. Then in 2009, a stretch of road between Catron Boulevard between Highway 79 and U.S. Highway 16 is expected to be rebuilt and widened.
These additional plans would bring the total cost of the connector route to approximately $50 million.
The SD/DOT was recently awarded for its work on designing the Southeast connector route; the project received honors as the best designed grading project and the best designed bridge project in South Dakota.
It was designed to provide a continuous route around Rapid City while controlling the number of access locations, information from SD/DOT explained.
It also provides a connector for local traffic and provides a smooth flow for tourist traffic heading to Mount Rushmore National Memorial.
The urban interchange bridge and three hard-to-design box culverts, including one that allows livestock to pass under the highway, helped make the project award worthy. CEG