Allen Plaza in downtown Atlanta is a $1.9 billion USD development that includes two million square feet of office space, 18,600 square meters (200,000 square feet) of retail and restaurants and more than 3,000 residences and 500 hotel rooms. The second of five buildings in the Allen Plaza complex is 55 Allen Plaza, a 14-storey high-rise that features a glass curtain wall skin in addition to a four-level below grade parking garage.
The building site at 55 Allen Plaza sought to maximize its square footage so single-sided forming against the dirt was specified. Atlanta’s ABE Enterprises installed their innovative shoring wall for the 12 meters (40 feet) below grade parking structure. The “ABE Wall” is built from the top down, rather than digging down to the required depth and installing the wall from the bottom up. This allows the developer to use the entire footprint of the property, as the wall is poured up against the dirt. However, since the shoring wall doesn’t leave a lot of room outside of the wall for installing conventional waterproofing membranes, the project team required an equally innovate concrete waterproofing system for the wall. One that could also address concerns with the ground water and subsequent hydrostatic pressure as well as contaminants in the soil.
The project team selected Kryton’s Krystol Concrete Waterproofing System to waterproof the shoring wall.
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.
Because it eliminates the need for external membranes, the Krystol system is ideal for blind wall applications like the ABE Wall. The system is easy to install and significantly less expensive than other conventional waterproofing systems, especially in the case of 55 Allen Plaza where access to the structure’s positive side was limited. And unlike waterproofing membranes that are often damaged during backfilling, Krystol lasts the lifetime of the structure, reducing the need for future maintenance and repairs.
To waterproof the below grade shoring wall at 55 Allen Plaza, the project team used a total of 7,300 kg (16,000 lbs) of Krystol Internal Membrane (KIM) and 1,600 kg (3,500 lbs) of the Krystol Waterstop System (KWS) to treat the joints. The project team found that by using the Krystol Concrete Waterproofing System, they saved considerable time in the construction process and reduced overall costs through the efficient elimination of numerous extra steps normally encountered when building these type of below grade walls. The ABE Wall, with KIM, provided the customer with unique savings in time and cost, engineering values that are important to all the parties in such a significant project.
“Kryton is a great team to work with and we are extremely impressed with their waterproofing products,” says Rick Anderson, President of ABE. “Their products do what they promise to do. Even though there’s water behind the walls at 55 Allen Plaza, it’s not leaking through the concrete because of Kryton’s crystalline technology.”