NASHVILLE, Tenn. — Building on top of a sewer tunnel can be a challenge, and intentional planning is crucial when the tunnel is 100-plus years old, runs the length of the site and is 11 feet in diameter where the structure straddles it.

Crain Construction confronted this scenario while building TownePlace Suites by Marriott on Charlotte Avenue, just west of Interstate 40 near downtown Nashville. The impressive Kerrigan Tunnel cuts through a large portion of the hotel’s footprint. (historic photo above)

Built in the 1890s, the Kerrigan Tunnel is the city’s oldest and longest combined sewer/stormwater tunnel. Measuring 16 feet across with the thickness of seven layers of bricks, at its largest point, the tunnel extends from the Vanderbilt University football field, through Centennial Park, near the Sounds baseball stadium and into the Cumberland River in Germantown. Originally built to handle creek and stormwater flow, it later became a combined sewer and today is a vital part of Nashville’s overall sewerage system.

Crain Construction employed careful planning and logistics while constructing the 10-story, 193-room hotel on a .66-acre site with only three feet to the property line on the east and west sides and seven feet on the north side.

“Working on a tight site and straddling the tunnel, we had to be very intentional and take a lot of precautions,” said Brent McGee, Crain Construction project manager. “A third-party inspector, hired by the city, was onsite to oversee all our work done near the tunnel.”

Crews used smaller track equipment to clear the site, slowing the demolition of three existing buildings. An emergency bypass pump system was installed onsite as a precaution in case the tunnel was damaged while foundations were being installed.

“We focused on installing the drilled piers on either side of the tunnel and poured the slab on grade over the sewer tunnel to protect it as soon as possible,” said McGee.

The building is designed so Metro Nashville will always have access to the tunnel should there be a need for repairs in the future. Exterior fence panels at the ground level are removable to allow for access to the tunnel within the footprint of the building, and the ceiling height of the first floor is 30 feet to accommodate any equipment the city might need to access or repair the tunnel.

The parking garage anchors the TownePlace Suites, with five levels of post tension concrete topped by five floors with structural studs with composite slabs. Street-level retail space fronts Charlotte Avenue.

Completion of the hotel is anticipated Spring 2021.

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