Abstract:
Developing lands adjacent to environmental cleanup sites can come with a high construction cost and typically dictates severely limited excavations. This is the case for many sites being developed around the Gowanus Canal in Brooklyn, New York. One of the main challenges is preventing contaminants from migrating into the site and the cost associated with dewatering sites with contaminated groundwater near the ground surface. Therefore, seldom are buildings around the Canal designed to have a cellar. However, the unique development conditions at the 420 Carroll Street project site required a cellar to be constructed in two buildings with a tunnel connecting them. The task:Â build a cellar 20 feet below groundwater for two new buildings and connect them in a neighborhood where cellars below groundwater typically aren't built with complex subsurface conditions. The solution:Â A soil mix mass Support of Excavation system with steel core beams for lateral support and drilled displacement piles for uplift resistance. A sampling and coring program was implemented for the soil mix and a load testing program was performed to confirm design parameters for the excavation and foundations. A dry excavation up to 20 feet below groundwater was accomplished at a distance of about 100 feet from the Canal.