Westlake Point

Westlake Pointe, an existing townhome development located in the Westlake area of Franklin County, began to experience slope instability and displacement due to soil subsidence. Having been constructed at the top of a steep embankment and in very close proximity to the shore of Smith Mountain Lake, the constructed slopes began to show signs of movement within two years after construction of the project had been completed. Residents of the community reported soil cracking, boardwalk and stairway displacement, and routine failure of the underground piping serving the sewer system.

Commissioned by the Westlake Townhome Property Owners Association (POA), ACS DESIGN inspected and assessed the existing site conditions in an effort to determine the cause of the slope failure and to provide recommendations for remedial action. Time was of extreme importance due to the fact that the slope failure posed an immediate threat to the structural integrity of the adjacent buildings; foundation failure and the possibility of building collapse created an uncomfortable sense of fear and uncertainty among the residents.

ACS DESIGN conducted a forensic investigation into the slope failure and directed geotechnical engineering consultants to determine the cause and extent of the problem. After detailed analysis and determination of the source of failure, ACS DESIGN then implemented a design-build solution that eventually resulted in the successful site rehabilitation of the project. A team of civil and geotechnical engineers and grading and utility contractors decided on a collaborative construction program that would eventually stabilize the embankment failure and restore the slope by constructing a modular retaining wall system. In the end, a segmental retaining wall, approximately 600 feet long and averaging 10 feet tall, was constructed adjacent to the Smith Mountain Lake Shoreline; in conjunction with this, an entirely new sewer collection system with a large sewage pump station was constructed behind the new retaining wall. Is important to note that all of the affected residential units (approximately 30) remained occupied during the course of construction. In the end, the POA spent approximately $750,000 on the site rehabilitation. Engineering analysis began in September 2003 and construction was substantially completed in August of 2004.

These photographs are typical of the existing site conditions at the top of the embankment slope. Exposed sewer piping was indicative of slope subsidence, and sewer piping failure. The exposed piping was a temporary sewer line repair needed to keep a sewage pump station in service such that the buildings could remain occupied.

These photographs are typical views of existing site conditions at Westlake Pointe during September 2003.  Fence, stairway, and boardwalk displacement were indicative of the extent and magnitude of the slope failure.  The fear of a potential heavy rainfall event kept most citizens of the development extremely worried that their homes could literally slide into Smith Mountain Lake.

	These photos show the completed site rehabilitation work.  As can be seen, the slope was stabilized and restored and the townhomes protected from further slope failure.
	This photo shows the new sewage pump station that was constructed to replace the four smaller pump stations that were affected by slope movement.  Though only a portion of the top is visible, the underground tank possesses a storage capacity of approximately 20,000 gallons and is equipped with a duplex pumping system and fully automated control and alarm panels.