Secant Pile Wall Design and Construction in Manhattan, New York

This paper presents the state-of-the-practice design and construction of a secant pile wall for a major real estate development in Lower Manhattan. At this site, the presence of a 1.5-meter wide rear alley between the adjacent buildings and the property line precluded the use of conventional underpinning. As an alternative, a secant pile wall was constructed to provide an excavation support system for the basement construction and to eliminate underpinning of adjacent buildings. The secant pile wall inherently created a dry excavation that avoided costly dewatering operations. The secant pile wall also served as the permanent foundation wall of the new building. The 58-meter long wall was completed in less than five months.