01/12/2006

Southeast Connector Wins Two Highway Design Awards

PIERRE, SD– The Southeast Connector in Rapid City recently received honors as the best designed grading project and the best designed bridge project in the state. South Dakota Department of Transportation (SDDOT) Operations Director, Darin Bergquist announced the award winners Wednesday, January 4, at the SDDOT/AGC (Associated General Contractors) Partnership for Highway Quality banquet in Pierre.

The nine-mile project involved the construction of a four-lane expressway with a center raised median and dedicated left turn lanes from Exit 61 on the east edge of Rapid City southwest to the intersection of US 16B and SD 79. This new highway was designed to provide a continuous route around Rapid City, while controlling the number of access locations. In addition to providing a connector for local traffic, the new alignment provides a smooth flow for tourist traffic heading to Mt.Rushmore and the Black Hills or for drivers continuing onto the Heartland Expressway.

A unique design item on this project is the single point urban interchange (SPUI) bridge at the intersection of US 16B and SD 79. Because the concept of a SPUI is relatively new to South Dakota, designers invested a great deal of thought and foresight into making the interchange a perfect fit to the tighter intersection spacing of SD 79. The use of retaining walls reduced the overall length of the bridge while allowing it to span SD 79 with no immediate bridge pier.

In addition, three box culverts on the project required considerable design efforts to accommodate the many special requirements of the project. One drainage site had to allow for livestock passage in addition to providing adequate water flow. Another box culvert was extended on both ends; each end being extended at different angles and constructed using differing construction methods.

The two railroad crossings located within this project utilized simple span prestressed concrete girder bridges with a retaining wall to minimize the length, at the same time meeting railroad clearances and matching roadway grade.

For aesthetics, a colored finish was used on the exposed concrete surfaces of the bridges and colored concrete was used on the retaining wall panels at the SD 79 interchange. This project has achieved its intended result in providing a clean, attractive corridor that blends well with the surrounding environment.

Each year the SDDOT and AGC award top construction projects around the state at the annual partnering meeting. A committee made up of members from both organizations and the Federal Highway Administration evaluate the nominations and select the top winners.