Geo Tech

Hunter College acquired land within the borough of Harlem in New York City to develop a new college facility. Two buildings were proposed: one a two- to eight-story classroom building and the other a multi-story student center building. The classroom building was designed to extend up to 16 feet below surrounding ground surface grades. The lower level of the student center building was designed at about existing ground surface grades.

The site is underlain by up to 10 feet of fill, 18 to 35 feet of loose to medium dense natural granular soils, then bedrock. Design groundwater levels were estimated up to 6 feet above the basement level of the classroom building. We evaluated the liquefaction potential of the natural granular soils to assess the feasibility of foundation bearing within the natural granular soils.

We developed recommendations for a waterproofed mat foundation designed as a pressure slab for the classroom building and also developed recommendations for rock socketed caissons for support of the student center building. During construction we reviewed the contractors' design of lateral earth support systems, underpinning of adjacent buildings and well-point dewatering systems. Field engineers, under our supervision, provided periodic on-site observation of earthwork and foundation construction activities.