Engineers Use Retaining Walls for Site Development Adjacent to Wetland

THE CHALLENGE

In 2012, Lake Osceola Realty Corp submitted a proposal for the development of a new 27,000 square foot (2,508.4 square meter) medical office building and parking area in Yorktown, New York. The proposed development was going to be built behind existing office buildings on a site surrounded by low-lying wetlands.

The significant grade change from the entrance of the development leading down to the office building and parking areas posed a challenge to the design and construction of the site. To make construction possible and the new offices accessible, developers needed a way to accommodate grade change requirements for the roadways leading to the building site while minimizing disturbances to the adjacent wetlands.

Redi-Rock retaining walls create space for extra parking at the Mount Kisco Medical Center development.

THE SOLUTION

Engineers from Civil Design Professionals and Site Design Consultants came up with a design that incorporated a combination of retaining and freestanding walls to support to the roadway and parking areas. They selected Redi-Rock to meet the challenges of this 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.

"The benefit of using Redi-Rock blocks on this site was the efficiency of both 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 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."

Local Redi-Rock producer, Mid Hudson Concrete Products, worked closely with WD Excavation & Contracting Inc. to supply the blocks for this project and provide input on the limitations and possibilities of each Redi-Rock block. This project truly showcased all that Redi Rock has to offer.

A combination of 60in (1520mm), 41in (1030mm) and 28in (710mm) Redi-Rock gravity blocks in the Limestone texture were used to complete the gravity 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. The curved design of some of the freestanding walls presented a slight challenge to the installers, however with the versatility of Redi-Rock, they were able to do some custom work on the blocks to achieve the radiuses necessary to complete the walls. The unique use of freestanding walls as an extension of the gravity walls provided the force protection needed, while giving a seamless, high-end look to the development. Finally, Redi-Rock caps were added to the top of the walls to complete the project.

Curved Redi-Rock freestanding walls in the Limestone texture act as a force protection barrier for this access road.

THE OUTCOME

In total,12,340 square feet (1,146.4 square meters) 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.

"From the retaining units, to freestanding blocks and decorative guardrails with finished caps, the customer got a solid, good-looking, high end project in a one-stop-shop purchase," Katie DeMarco of Mid Hudson Concrete Products noted.

"The most enjoyable part of building the walls were that two family-run businesses, passionate about what they do, worked together to take raw materials and turn them into an installed Redi-Rock product that speaks for itself aesthetically and structurally," explained Dubray.

This project was the recipient of the 2015 Rocky Award for "Freestanding Wall of the Year" from Redi-Rock International. The Rocky Awards are an annual honor recognizing the best Redi-Rock projects completed each year across the globe.

PROJECT DETAILS

Project: Mount Kisco Medical Center #176 Customer: Lake Osceola Realty Corp Engineer: Civil Design Professionals and Site Design Consultants Manufacturer: Mid Hudson Concrete Products Installer: WD Excavation & Contracting Inc. Location: Yorktown, New York Year Built: 2013-2014