By Jeannie McElroy and Greg Yoko

During the past decade an increase in various geosynthetic material solutions have been developed, tested and analyzed. As a result, the use of geofabrics and geotextiles are becoming much more prevalent in land development. In addition to serving as moisture barriers, these materials also provide reinforcing strength to soil in an effort to reduce erosion or to increase soil stability.

New home construction has boomed over the last decade and many local and national residential construction companies are answering the demand for housing by building more homes on less land.  These companies need creative, productive and cost effective solutions to their development needs.

In the Atlanta area, like many others, local and national residential construction companies are answering the call with new home and condominium developments. Winmark Homes, one of the area’s local builders since 1990, was constructing a residential subdivision called Castleberry Community in Cumming, Georgia, a northern suburb of Atlanta

Building space is a precious commodity for residential homebuilders and the Castleberry community is no different.

In order to utilize more building space when developing the land chosen for the Castleberry Community, ECM Modular Walls was contracted to build a large slope using high-strength geotextiles and a secondary reinforcement geotextile, which also provides erosion control.

Some major challenges for this project were building a wall of significant size with enough reinforcement while keeping the look of a beautifully manicured landscape. In many areas of the slope, the height peaks at 30 feet. The total amount of face is 6,596 meters2 (71,000 feet2).

Three types of geosynthetic materials were used to provide reinforcement and erosion control. Two types of high-strength geotextiles were utilized for the core reinforcement of the slope.

The two geotextiles chosen were TenCate Mirafi® PP400 and PP800, which are blended polypropylene and polyester geosynthetics.

The third geotextile selected was TenCate Mirafi® Miramesh woven open mesh biaxial geosynthetic, produced from UV-stabilized green yarns. It is specifically designed for secondary reinforcement and surface erosion control for steepened slope applications. This biaxial geosynthetic was installed as the face wrap material within wire baskets then hydroseeded for vegetation growth.

Mirafi® Miramesh replaces the need to use two layers of material on the face of the slope by combining the function of reinforcement along with promoting the growth of vegetation for a more natural erosion control application.

The benefit of using vegetation on the face of the wall outweighed other options because it was more cost effective when compared to brick facing, and by maintaining the natural beauty of the landscape, it provided an aesthetically appealing choice.

Each of the geotextiles was installed beginning at the compacted subgrade. TenCate Mirafi® Miramesh was placed inside the .91 meter (3 feet) welded wire baskets to provide a stable platform for hydroseeding. Mirafi® PP400 embedment lengths varied but were around 4.5-6 meters (15-20 feet). The wall was seeded immediately after completion to allow grass to grow as quickly as possible on the face of the wall. The project installation lasted approximately 10 months. 

The wall was completed successfully and Winmark Homes opened Castleberry Community in mid 2005. Due to the fact that these materials made a difference, a daunting interference for a building and development company is now a successful and profitable project.  SLDT