H&H is a key design subconsultant for the accelerated schedule design-build replacement of the 130-year-old Metro-North Railroad Park Avenue Viaduct, which spans from 97th to 131st Street in Manhattan. This vital structure supports four Metro-North tracks, serving over 750 trains and 200,000 commuters daily. The project involves replacing 49 spans, including steel superstructure, columns, foundations, and tracks, as part of a major state-of-good-repair effort for MTA/Metro-North.
H&H is the Engineer of Record, overseeing the design and construction of new substructures and foundations. These include 50 bents supported by over 900 rock-socketed micropile foundations. The project faces significant constraints, such as limited overhead clearance and space beneath the existing viaduct, strict schedule limitations, and minimizing disruption to commuters and local parking. To meet these challenges, H&H collaborated with the contractor to develop innovative solutions, including a unique casing overburden drilling system and a down-the-hole hammer to improve drilling efficiency.
The substructure design must accommodate heavy rail loads, seismic forces, and future utility work. To meet these criteria, H&H worked closely with the contractor to design efficient rebar solutions and select self-consolidating concrete mixes to facilitate construction in tight spaces, ensuring successful and timely project completion.
Transportation Projects
