The detour is now open and traffic is flowing smoothly. Demolition is underway on the existing bridge in preparation for construction of the new 4-span structure which will follow the same alignment as the existing bridge.
In the roadway between the Station 46 bridge and the Pleasant Cove crossing our subcontractor Keller has been installing 2,422 wick drains. Because the underlying soils below the road are soft and wet, the wick drains are installed to bedrock on a regular pattern. When they are finished, we will install about 6 feet of gravel on top and that will sit for about one year. During that time, the wick drains will ‘wick’ water out of the underlying soils and it will drain out through the gravel layer. The added weight of the gravel surcharge accelerates the process.
The result will be the underlying soils will consolidate and strengthen and future road settlement will be minimized. Part of our work involves permanently raising the existing road several feet to prevent flooding. But this additional weight would likely cause new settlement, if not for the consolidation from the wick drains.
Following demolition, the next steps at the Station 46 bridge will be installation of cofferdams at abutments and the three piers to allow pile driving and concrete work.