The I-85 Rehabilitation (MM77 to MM84) project replaces the CSX railroad overpass over I-85 and rehabilitates three miles of the interstate. The project schedule was accelerated to be included in the I-85 Phase I and II Design Build Project. The replacement bridge is designed to provide horizontal and vertical clearance for (future) eight lanes of I-85, maintain two lanes of I-85 in each direction during construction, and maintain vehicular and rail access to third party stakeholders.

CSX required the new bridge to carry two tracks of Cooper E90 loading. Due to the geometric site constraints, two spans of 13’-6” tall through girders were designed to span the future 8-lane section. A third shorter span carried CSX over Dewberry Road. Minimizing excavation was critical as the site is adjacent to an area of known contamination (and a superfund restoration site). Eight-foot-diameter drilled piers were used for the interior bents due to the limited median width and proximity of I-85 traffic. Steel pile foundations were used at the end bents. Several retaining walls were required to hold the fill for the realigned railroad. Soldier pile retaining walls, cast-in-place retaining walls, and soil nail walls were used for various locations. Anchored temporary walls were also required for the staging of the project.

Carolina TEA provided project management, railroad coordination and turnkey design services for the development of final railroad and structure plans, permits, and preliminary MOT, ROW, utility and roadway plans for inclusion into the Design Build package. Derek developed a structure replacement and MOT concept that satisfied all geometric criteria as well as SCDOT’s goals to maintain two lanes of traffic in each direction on I-85. He coordinated subconsultant services including field surveys, geotechnical investigations & designs, environmental studies and NEPA documentation, wetland and threatened and endangered species surveys, utility coordination, hazardous materials surveys, pipe inspections, SUE, and provided construction engineering services.