416 and 420 Kent – High Rise Mixed-Use Development

McLaren Engineering Group provided full engineering design services for three 23-story high rise towers located at 416 and 420 Kent Avenue in the Williamsburg section of Brooklyn, NY. The modern mixed-use towers are comprised of 857 apartment units, commercial space, underground parking and amenity spaces. The total constructed floor area is over 800,000 square feet.

McLaren’s team proved its versatility by servicing the structural, geotechnical, marine and civil portions of the high rise Kent Avenue project. Tax abatement deadlines created a need for a fast-track design schedule requiring a permit set of structural drawings to be submitted within a one-month timeline. Borings were expedited to facilitate a preliminary pile design required to submit a structural permit set. Various McLaren divisions worked together seamlessly to meet project deadlines.

Shoreline Improvements

McLaren engineered the design of the bulkhead and 40-foot-wide waterfront walkway along the East River. The Marine Division assisted the Structural Division with the flood loadings on the buildings, and flood resistant design requirements. The shoreline improvements integrated mitigation design to prevent further pollution of contamination found on-site.

Cantilevered Bays and Changing Floor Plans

80% of the apartments have a corner window

At the forefront of the water, this unique high rise development was designed with views in mind, with 80% of the apartments having a corner window. McLaren engineered cantilevered bays with diagonal struts and hanging columns to support this unique design feature. The diagonal struts were to transfer cantilever loads back into the building.

One of the biggest challenges is that the floor plans changed at every level, requiring column spacing maximization while minimizing the slab structure depth. McLaren utilized the central concrete core as shear wall to provide lateral restraints. Transfer girders and walking columns were used to create these larger open spaces, and the use of specialty stud rails maximized span lengths between columns while minimizing concrete slab depths.

416 and 420 Kent Built to Resist Hydrostatic Forces

A building on the waterfront comes with it’s own challenges. A concrete pressure slab, supported on 14 inch diameter steel pipe piles and concrete pile caps, is being utilized in the below grade parking basement to resist hydrostatic forces from the East River during a storm surge. The pipe piles driven to competent rock, depths ranging from 80-120 feet, serve as bearing piles with a 200 ton compression capacity and 80 ton tension capacity.

Rooftop

At the rooftop, McLaren engineered the structure to carry the loads of the outdoor lounges, herb gardens, and rooftop swimming pools (as well as the openings the pools fit into).

Awards

This project was selected for the prestigious Award of Merit by the Concrete Industry Board, the local chapter of American Concrete Institute (ACI), and New York’s Best Buildings – Trend 1: Totally out-there architecture by the New York Post in 2018.