I-270 at Watkins Mill Road Interchange

One of the largest new interchange projects recently designed and constructed in Maryland, this project has helped to relieve congestion on one of the most heavily traveled roadways in Montgomery County. EBA provided construction management and inspection services that helped the client and contractor achieve project completion 6 months ahead of schedule. The complex new construction included:

• 15 structures, including 12 steel girder bridges and 2.3 miles of four lanes with resurfaced shoulders for Watkins Mill Road, spanning I-270 and a tributary to the Great Seneca Creek.
• 2 miles of on-ramps and off-ramps, including multiple retaining walls, to provide access from Watkins Mills Road to I-270.
• Off-ramp for MD 124.
• Restoration and relocation of the mile-long unnamed tributary that runs alongside SB I-270 to the Great Seneca Creek.

EBA conducted detailed inspections and in-place sampling and testing of concrete, soil and aggregate compaction, and HMA placement; monitored CPM schedules and cash flow; and coordinated and oversaw utility relocations.

Construction work was particularly challenging, due to being located in an extremely sensitive environmental area and within the footprint of an existing tributary. As such, scheduling became critically important to avoid interrupting stream flow while minimizing impacts to aquatic life. In addition, erosion and sediment control proved equally complex due to weather conditions and the large impervious ground area upstream of the tributary being relocated within the project limits.

The project received multiple 2021 awards from the Maryland Quality Initiative, Engineering News-Record, Construction Management Association of America, and Heavy Construction Contractors Association.