Buckhead is one of Atlanta’s most important and trendy business districts noted for its shopping, entertainment and high-end residential neighbourhoods. Running north/south through the district, the Peachtree Road corridor is characterized by high-rise developments, the most recent being the striking Terminus 100 building. At a height of 148 meters (485 feet), Terminus 100 features 26 floors and 198,120 meters² (650,000 feet²) of mixed-use space (ground floor retail and residential) topped by a glass crown. Terminus 100 is the first of five high-rises planned by Cousins Properties on the 4.046 hectares (10-acre) site.
Atlanta’s ABE Enterprises installed their innovative “top down” shoring wall in the 2-level below-grade parking garage. Rather than digging to the required depth and installing the wall from the bottom up the “ABE Wall” is constructed in stages beginning at grade level. This allows the developer to use the entire footprint of the property, as the wall is poured against the dirt leaving no room for exterior applied waterproofing membranes. As a result the project team required an equally innovative concrete waterproofing system in place of conventional membrane systems.
The project team’s first choice for a waterproofing system was the Krystol concrete waterproofing system. During construction, access to the structure’s positive (wet exterior) side was limited so Kryton’s Krystol Internal Membrane (KIM) admixture was used in the below-grade walls to waterproof the parking garage. Because KIM is added directly to the concrete mix, it eliminates the cost of installing, often unreliable external membranes.
Unlike traditional membranes, KIM will not crack, peel, tear, separate at the seams or deteriorate under UV exposure. KIM becomes part of the concrete matrix and will last the lifetime of the structure. It is unaffected by surface wear and tear and cannot be damaged by backfill. Construction time is also shortened as there is no need to schedule membrane application and no wait time to backfill.
The result is extensive time savings, lower cost of construction and reduced downstream maintenance and repairs.
A total of 1097 cubic meters (1,200 cubic yards) of KIM-treated concrete were used to waterproof the below-grade shoring walls at Terminus 100. In addition to KIM, the Krystol Waterstop System was also used to treat the construction joints. The advanced joint design system replaces the need for complicated, labor intensive PVC or bentonite applications and uses the same Krystol technology to permanently waterproof static construction joints.
Both the KIM admixture and the Krystol Waterstop System are part of the world’s only complete crystalline concrete waterproofing system. Based on Kryton’s proprietary crystalline waterproofing technology, the Krystol system turns concrete into a permanent, waterproof barrier. When added or applied to concrete, Krystol causes millions of needle-like crystals to form, filling the spaces between concrete particles, blocking the penetration of water and corrosive elements and resisting hydrostatic pressure. Over time, incoming water causes additional crystals to form, self-sealing small concrete cracks.
By using the Krystol Concrete Waterproofing System, a considerable amount construction time and cost was saved. The use of KIM eliminated numerous steps traditionally encountered with waterproofing this type of shoring wall and created the foundation for a watertight structure. Hardin Construction was so pleased with the performance, the Krystol system has already been selected as the waterproofing solution to be used in the upcoming Terminus 200 project.
Shoring wall contractors ABE Enterprises also expect to begin incorporating KIM in their new shotcrete style shoring walls, which will be the first of their type on the east coast of the United States.