City of Columbus in Columbus, Ohio, awarded to Granite from Watsonville, California, USA, the EUR224.30 (USD267) million contract for the Lower Olentangy Tunnel project.   

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.  

The construction of the LOT main tunnel will consist of approximately 5,181 m (17,000 feet) of 3.66 m (144-inch) hand-mined diameter tunnel and will be mined with a TBM 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  2.29 m (90 inches) in diameter will also 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 is expected to begin in March 2021 and expected to conclude in December 2026. Visit   https://www.columbus.gov/ and https://www.graniteconstruction.com/. 10/21.