Grade changes and wetlands presented a major challenge to designers of the new Mount Kisco Medical Center.The access road to the development needed to meet the grade change requirements, minimize disturbance to the wetlands, and keep the site fully functional during construction. See how the design team was able to reach these goals with innovative use of gravity retaining walls.
In 2012, engineers were faced with a major challenge to create an access road for a new medical development. The site had significant grade changes and was surrounded by low-lying wetlands.
The developer, Lake Osceloa Realty Corp., turned to engineers from Civil Design Professionals and Site Design Consultants for a solution that combined retaining and freestanding walls to support the new roadway and parking areas while also protecting the wetlands. Redi-Rock retaining walls produced by local manufacturer, Mid-Hudson Concrete Products, were chosen for the project because of “cost, speed of installation, aesthetics and sensitivity to work adjacent to wetlands,” said Matt Moran, representative for Lake Osceola Realty Corp.
Redi-Rock is a precast, large block retaining wall system engineered to harness the power of gravity to build tall retaining walls. Redi-Rock blocks stack together like giant Lego blocks to install quickly, without the need for additional reinforcement in many applications. Minimal excavation is required to install Redi-Rock, making it possible for this project to be built quickly without encroaching on the wetlands surrounding the site. Plus, Redi-Rock was able to achieve the height requirements called for in the design of the walls without requiring reinforcement.
“The benefit of using Redi-Rock blocks on this site was the efficiency of excavating for the walls and installation of square footage per block,” said Matthew Dubray, working foreman for WD Excavation & Contracting Inc., the installer of the project.
“Geogrid was not required on this, which would have been necessary for most smaller modular block systems. Not having to over-excavate areas behind the walls allowed us to keep the site functional during installation by not having massive cuts and stockpiles of fill.”
Redi-Rock gravity blocks in the Limestone texture were used for the retaining walls, which were 12 feet (3.7 meters) tall in the highest spot. Redi-Rock Limestone freestanding walls were built on top of the gravity walls to act as a guardrail along the roadway. This unique use of freestanding walls as an extension of the gravity walls provided the force protection needed, while giving a coordinated, high-end look to the development.
In total, 12,340 sq ft of Redi-Rock was used on the project, which was completed in 2014. “It has been over a year and there have been no signs of movement or settlement. It looks far better than poured concrete,” said Moran.