- This complex marine project called for installation of an overhead transmission circuit spanning the Patapsco River adjacent to the Francis Scott Key Bridge in Baltimore, Maryland. The new overhead line segment is supported by new steel monopole towers at 8 locations, 5 of which are in the Patapsco River. These in-water towers range in height from 126 feet to 397 feet above the Patapsco River. The project features large concrete foundations supported by 24, 36, 42, and 54-inch steel pipe piles with wall thicknesses up to 1.25 inches. The foundation design utilizes a combination of precast and cast-in-place concrete to facilitate construction. The main channel tower foundations are protected by a heavily reinforced concrete and steel fender ring vessel collision protection (VCP) system.