Overview

Work began in March 2020 to replace a bridge on Second Street that runs over the Flint River in the Village of Columbiaville. The original bridge was built in 1934 and had experienced severe damage rendering the bridge unsafe. The beams of the bridge were severely deteriorated, the joints had heavy spalling along the beams, and there were holes in the decking. The superstructure of the bridge was last replaced in 1990.

Hardman Construction selected G2 to design cofferdams for the construction of the bridge’s foundation system to allow for construction below the Flint River’s surface. The $3.4 million project was completed and ready for traffic in November 2020.

Challenges/Solutions:

Hardman Construction selected G2 to design cofferdams with complicated bracing systems and reaching depths of ~25 feet below water surface to allow for the construction of the bridge’s foundation system below the Flint River’s surface. The construction of a cofferdam is unique process that begins with driving vertical steel sheets into the subsoils of a marine environment to form an enclosure that will later be drained. While still filled with water, the cofferdam is dredged to the desired depth and foundation piles are driven into place.  After the pile driving operations are complete, a piping system is used to pour concrete on the flooring of the cofferdam. The concrete acts as a seal and once cured allows the water to be pumped out of the cofferdam creating a safe environment for the contractors to begin constructing foundations.