YU & Associates (YU), as a team member on the NBBJ Architecture PLLC (NBBJ) design team, provided geotechnical and environmental engineering, and hazardous materials survey and abatement design services for the rebuild / restoration and hazard mitigation of the Coney Island Hospital campus. The project seeks to advance NYC’s comprehensive resiliency plan in the wake of the devastation caused by Hurricane Sandy in 2012, ensuring critical protection and construction of a new permanent flood mitigation structure at the campus.
The proposed 15-story CSS Building, with parking garage at ground level (about 65,000 sf footprint), will be constructed along the northern perimeter of the site along with demolition of a few existing structures. A 4-ft high concrete flood wall about 2,000 ft long with vehicle and pedestrian gates will be constructed along with utility work and other site improvements.
A subsurface investigation with test borings, geoprobes and cone penetration tests was performed to determine the subsurface conditions and soil parameters for foundation design and for development of environmental site remediation approach and design. YU also performed hazardous materials survey and abatement design as well as air monitoring during demolition of existing buildings.
Among different deep foundation alternatives evaluated, YU recommended 16-inch diameter displacement auger cast piles about 70 feet long with 130-ton design capacity for support of the new building. A 12-ft deep steel sheet pile system was recommended as a seepage cut off below the base of the concrete flood wall. Excavation, dewatering and excavation support are anticipated for the construction of a new on-site underground detention basin.
Environmental investigation disclosed soil/groundwater contamination. Remedial Action Plan was developed, and Health and Safety Plan was prepared for worker protection during construction.
