The bridges involved in the project are the East Lincoln Avenue bridges in Pelham and Mount Vernon, the Saw Mill River Parkway bridges over the Saw Mill River, and the U.S. Route 1 bridge over the Mamaroneck River in Mamaroneck. The bridges were combined into one project to allow for a more efficient contracting and construction process.
The project will enhance safety and improve the region’s resiliency during storm events. The team is making drainage improvements and reconstructing roadways prone to flooding.
Drainage improvements on this project segment include replacing the Hutchinson River Parkway stormwater system. New flood walls are also being installed, along with a bypass culvert, to convey precipitation from storm events into Pelham Lake.
Upon completion of the work, the Hutchinson River Parkway will be able to withstand 50-year storm events. “The increased elevation will improve resiliency, enhance safety, and reduce instances of bridge strikes by over-height vehicles,” says Heather Pillsworth, an NYSDOT Public Information Officer.
At Lincoln Avenue, the team faced a challenge in dealing with an existing high-voltage transmission line that needed to be maintained during the construction of the new bridge. Doing so required construction of an intricate temporary support system using steel H-Piles. Once the new bridge was installed, the line was supported and framed into the new structural steel girders.
“To ensure traffic flow along this critical piece of infrastructure, the team installed a temporary bridge carried traffic during construction,” says Pillsworth.
The team is installing 5,000 timber piles and a load transfer platform along the Hutchinson River Parkway. The load transfer platform consists of 4 feet of engineered aggregate and multiple layers of synthetic geogrid.
Two new bridges that span the Saw Mill River are replacing the original bridges that were constructed in 1930. The new bridges are modern, single-span, steel girder bridges. They are several feet higher than the previous bridges and can meet 100-year flood projections. High-capacity drainage systems were installed to handle stormwater runoff.
The team is reinforcing and strengthening the new bridge with a steel liner to protect it from scour. The new bridge will be wider and include a pedestrian walkway.
An existing natural stone arch structure that supports nearby Meighan Park is over 100 years old and needed significant repair. Instead, the team is removing it and replacing it with retaining walls and an embankment upon which to construct the park.
A 66-inch sewer that crosses the bridge is also being replaced. This new sewer will have a life expectancy exceeding 75 years.
Scheduling this part of the project has been challenging. The team had to schedule around the tide schedule of the Mamaroneck River because of its location in the tidal zone.
The budget for the design-build project is $115 million. It is being funded via a combination of state and federal funds (80 percent federal/20 percent state) and is on budget.
When the NYSDOT completes the Lower Westchester Bridge Bundle project, key roadways in Westchester County that had been prone to flooding will be more resilient. This will give motorists a safer and more reliable ride. The new bridges will serve the area for many years to come.