This crossing was delivered along the north-south Interstate 77 corridor, and approximately 30 miles from the state border between West Virginia and Ohio. The crossing’s principal obstacle was the interstate itself – which may otherwise be characterized as a prominent four-lane divided highway. Located in the Marietta Plateau region of the Appalachian Highlands, the project area possesses somewhat prominent topographic expression with both steep hills and deep valleys. As a result, a significant elevation differential exists between the crossing’s end points. Moving from west to east, there is a net elevation loss of approximately 220 feet. The east side of the crossing, which exhibits the lesser elevation, was the nominal entry point. Due to workspace and topographical considerations, the east side was utilized to facilitate pull section staging and fabrication. The HDD profile followed a 2,000-foot radius of curvature with various points of curvature and points of tangent along the subsurface path. The bore path crossed I-77 approximately 108 to 109 feet below the existing ground surface and Valley Road approximately 87 feet. The construction milestone included 100 ft 36” conductor casing 100 feet; Drilled out 2,175 ft with 10 5/8 pilot with gyroscopic steering; 18” ream pass, 30” ream pass, followed by swab pass; Moved rig to exit side and delivered a successful pipe pull with 3 mid-welds.
