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PROJECT HIGHLIGHTS
Atlanta airport slope stability
General Contractor: C.W. Matthews Contracting Co. Inc.
Design Engineer: Propex GeoSolutions
HPTRM manufacturer and fabricator: Propex GeoSolutions
HPTRM installer: Athena Construction Group Inc.
HPTRM product: ARMORMAX®
Hartsfield-Jackson Atlanta International Airport is the world’s busiest airport, accommodating more than 100 million passengers and more than 950 thousand flights annually. Heavy rainfall was causing severe erosion and slope failure along a 1,000-square-yard (836-m2) steep hill next to the fifth runway. If not corrected, the increasing erosion and surficial failures could have grown to create a globally unstable slope. The client requested a solution that would stabilize the slope and provide a vegetated outcome that would be easily maintainable.
The stabilization material had to be geotechnically engineered to provide surficial stability against a 4-foot (1.2-m) failure, and the matting needed to be durable and resilient up to a 50-year design life. To meet these criteria, a high-performance turf reinforcement mat (HPTRM) and 9-foot (2.7-m) B2 engineered earth anchors were used.
All work was completed behind security within the aircraft movement area of the airport. Large equipment could not be used above the slope because of the proximity to an active runway. Traditional armoring solutions, such as rock riprap, would have required using multiple large machines. In contrast, the equipment used to install the HPTRM is compact and minimal.
Initial analysis of the slope showed that the factor of safety (FS) was 1.0. This level of FS can be classified as a pending failure because any new element, such as heavy rain, can push the slope over the stability threshold. After the HPTRM was installed, the FS was significantly increased to more than 1.3.
Additionally, the HPTRM helps lock in seeds and promotes rapid root mass development. After installation, the slope was quickly vegetated and remains lush today.
Are “earth anchors” what the article calls “slope reinforcement” on this project ? The summary talks more about turf reinforcement. Regarding revegetation, wouldn’t an organic ground cover accomplish the same job at less cost ? What does that HPTRM used on this project do that organic mats won’t ?