KCI’s multi-disciplined engineering team delivered full design for three 23-story mixed-use towers at 416 and 420 Kent Avenue in the Williamsburg area of Brooklyn, New York.
Connected by a seven-story podium, the development includes 857 residential units, ground-floor commercial space, and underground parking. To maximize residents’ views of the nearby river, KCI engineered bold building extensions that define the towers’ distinctive profiles. This approach enabled nearly 80 percent of the apartments to function as corner units with expansive views of the surrounding landscape, while the structural design maintained efficient, streamlined floor layouts.
Accelerated geotechnical borings were performed inside the existing building prior to demolition to support preliminary pile design and enable a fast-tracked structural permit submission schedule. To support the architectural vision, KCI’s structural team engineered a concrete superstructure with cantilevered balconies, diagonal struts, hanging columns, transfer girders, and walking columns, along with a central concrete shear wall to provide lateral resistance. Stud rails were incorporated to maximize slab spans while maintaining minimal slab depths, accommodating floor plate variations at every level. The design strategy extended to the rooftops, which were engineered to support heavy live loads and amenities including outdoor lounges, herb gardens, multiple swimming pools, and Building Maintenance Units (BMUs) atop each tower. Structural considerations accounted for pool embedment, drainage integration, and long-term durability.
KCI also provided comprehensive civil engineering services across the multi-building site, including stormwater management in accordance with NYCDEP and NYSDEC requirements, sediment and erosion control, utility coordination, and sidewalk and pavement modifications. The team supported permitting and approvals with multiple city agencies and prepared site safety plans, grading and utility plans, sewer connection filings, Builders Pavement Plans, vault permits, street tree documentation, and a Stormwater Pollution Prevention Plan under the SPDES General Permit.
On the waterfront side, KCI’s civil and marine/coastal engineering teams designed a 40-foot-wide public promenade and bulkhead along the East River, extending access to the NYC Ferry service. The shoreline improvements incorporated flood-resilient features, flood load analysis, and compliance with floodplain development requirements, while also addressing pollution mitigation measures to prevent the spread of existing site contamination. Below grade, the parking garage was engineered with a flood-resistant concrete pressure slab supported by steel pipe piles driven to rock to resist hydrostatic uplift during storm surge events.
During construction, KCI provided special inspections for the installation of more than 800 piles and redesigned pile caps to accommodate piles that were out of tolerance. When supply chain delays impacted material availability, the owner directed a change from round steel piles to H-piles, requiring the foundation system to be adapted during installation. By responding quickly to evolving site conditions and material constraints, the team maintained momentum without compromising structural integrity.
The 416–420 Kent Avenue development now stands as a landmark achievement, combining innovative structural design, coordinated civil and geotechnical engineering, and resilient waterfront infrastructure to transform Williamsburg’s skyline and enhance the Brooklyn waterfront for years to come.
