Granite Construction announced March 8 that it has been awarded the Lower Olentangy Tunnel project by the city of Columbus in Columbus, Ohio. The $267 million contract is anticipated to be booked in Granite's first quarter 2021 backlog.

The Lower Olentangy Tunnel (LOT) project aims to improve water quality and reduce the risk of exposure of humans to waterborne pollutants by reducing overflows from the sewer system into creeks and rivers during flooding. LOT will connect into the upstream end of the previously Granite-constructed OSIS Augmentation Relief Sewer (OARS) at Vine Street. The upstream end of LOT will be located north of Lane Avenue and will provide hydraulic relief to the three existing sewers that are in close proximity of each other: Franklin Main Interceptor Sewer, Olentangy Main Interceptor Sewer and OARS.

"We have had an excellent relationship with the city of Columbus and are happy to once again work on their tunnel systems," said James Nickerson, Granite division vice president. "Since this project dovetails into a tunnel project we completed for the city of Columbus approximately five years ago, we have a clear understanding of the project and our client's expectations."

The construction of the LOT main tunnel will consist of approximately 17,000 ft. of 144-in. hand-mined diameter tunnel and will be mined with a tunnel boring machine and constructed of precast concrete segments. The main tunnel will be constructed of concrete segments with three main shafts at Tuttle Park north of Lane Avenue, Gowdy Field near Third Avenue and Olentangy River Road and Vine Street.

A microtunnel 90 in. in diameter also will be constructed to relieve OARS near Second Avenue, which will begin at the Second Avenue and Perry Street intersection and flow west into LOT at the Gowdy Field Shaft.

Construction was expected to begin in March 2021 and is expected to conclude in December 2026.

For more information, visit graniteconstruction.com.