Maine facility levels areas, tackles drainage issues
When the Maine General Hospital in Augusta, Maine, broke ground on its new facility, the hilly site required 23,000 sq ft of retaining walls to create level areas and deal with drainage issues.
Designers chose Redi-Rock to create the retaining walls for the project because it is a versatile system with the ability to build gravity retaining walls, reinforced retaining walls and freestanding walls. This allowed designers to create a coordinated look for the project with a single system. Redi-Rock performs well in water applications. Because the blocks are created using wet-cast, 4,000-psi, air-entrained concrete, they stand up to freeze-thaw cycles and have a proven track record in storm water applications across North America.
A stream through the property created some challenges for road construction due to underlying soft clay soil. “The steel arches for the bridge were on a pile foundation, so settlement would be minimal, but the Redi-Rock walls on either side of the arches would be sitting on the natural soils. Settlement of these walls was anticipated to be up to 2 in.,” said Jeff Benway, P.E., of SFC Eng.
How did engineers solve the problem? “The blocks were laid out so that there would be a joint at each side of the arch. This would allow the side walls to move and not affect the walls on the arch,” Benway said.
The hospital also featured a storm water detention basin. “This basin is somewhat unique in that it was at a relatively high point on the site with a significant slope below it,” Benway said. “The wall was built to create an area for the basin on top of this slope. [It] ‘hides’ the basin from people driving up to the hospital and at the same time creates a nice entryway.”