Lockbourne Intermodal Subtrunk (LIS)

The LIS is an extension of an existing 168-inch sewer that currently passes north of the Village of Lockbourne and terminates at the Southerly Wastewater Plant on S. High Street. The proiect area extends along numerous city and county roadways as well as the City of Lockbourne, along Big Walnut Creek and ends at the existing Norfork and Southern Intermodal Facility.

The finished diameter for the tunnel, which was excavated using a micro tunnel boring machine (MTBM), is 78-inches from Rowe Road to Ashville Pike and reduces to 60-inches for the remaining distance, which was installed by open cut. The tunnel portion was constructed of centrifugally cast fiberglass reinforced mortar pipe jacked into place behind the micro tunnel boring machine (MTBM) as it mined through the soil and rock. Hydrogeological and geophvsical studies were performed to select the best technology for tunnel construction and to ensure the MTBM was desianed to operate in a manner that reduced impacts to nearby residents and wells. The tunnel was constructed at a depth of 30 feet below ground at the launch site and ended at a depth of 65 feet below ground as a result of ground elevation increasing.

Intermediate shafts were constructed to provide jacking and service locations during construction and provides for future connection points as the service area develops. Overall, the entire project was completed by summer of 2020.