Urban design and construction challenges

    Design and construction of New York City’s multi-billion-dollar transit expansion projects requires a level of detailed coordination that is among the most complex in modern-day urban engineering. Photo: Matrix New World Engineering

    What is it going to cost and how long will it take? Those are the top two questions before undertaking any simple construction project. So, what if the answer to those two questions are “Billions of dollars” and “Years”? If you’re familiar with the current state of New York City infrastructure, you might guess I am discussing the ongoing Second Avenue Subway Project, the East Side Access Project, or the Hudson Tunnel Project.

    These are three separate expansions to a severely overtaxed existing rail/subway system, with new lines and connections to the north (Second Avenue), east (East Side Access), and west (Hudson Tunnel) of midtown Manhattan. Each is vitally important to the future of New York City’s commuter rail service, and Matrix is the lead environmental subconsultant for each of these massive, historic projects.

    Design and construction of these multi-billion-dollar expansion projects requires a level of detailed coordination that is among the most complex in modern-day urban engineering.

    The Second Avenue Project, first proposed in 1919, required extensive tunnel boring under one of the most densely populated and valuable real estate on the planet. It included major modifications to the existing 63rd Street and Lexington Avenue Station (without interruption to passenger service), as well as intricate demolition and surface excavation work. Phase I opened Jan. 1, 2017, with new entrances at 72nd, 86th, and 96th streets. Phase II is set to begin in the near future with an extension north to 125th Street.

    Significant coordination of maintenance and repair to the existing tubes is required during new tunnel construction. Photo: Matrix New World Engineering

    This is New York City’s largest subway expansion in more than a half-century, requiring multiple low rise building demolitions and many more alterations and modifications to existing structures. Environmental investigation and hazardous material testing was key to these endeavors, beginning at the property acquisition stage and continuing through remediation and demolition/construction efforts.

    The East Side Access Project is widely viewed as the country’s largest and most expensive transportation project, connecting the Long Island Rail Road (LIRR) to Grand Central Terminal. The project includes a new six-mile-long tunnel beneath the East River, significant alterations/modifications to the existing Sunnyside Yard in Queens, and construction of a new East Side Station being built below and incorporated into Grand Central Terminal.

    The Hudson Tunnel Project, originally referred to as the Access to the Region’s Core (ARC) Project, has recently resumed under a new name. It features construction of a new rail tunnel beneath the Hudson River connecting the existing Northeast Corridor to a modified Penn Station in New York. In addition, rehabilitation, modernization, and repairs are required within the existing 105-year-old North River Tunnel, which was severely damaged by Superstorm Sandy flooding.

    Based on the level of dilapidation within the existing North River Tunnel, system-wide repairs can’t happen until the new tunnel is completed, thereby avoiding any serious impact to current rail capacity. This will require significant coordination of maintenance and repair to the existing tubes during new tunnel construction.

    Serving on each of the projects’ design and construction teams as a lead environmental resource, Matrix is often tasked with the initial assessment, investigation, and testing; identifying potential environmental areas of concern through Preliminary Assessment (i.e., New Jersey sites); and Phase I Environmental Site Assessment (i.e., New York sites) studies. 

    These efforts are conducted through multidisciplinary efforts to identify, characterize, quantify, and delineate targeted areas, structures, and/or subsurface elements; supplemented through more comprehensive Phase II Site Investigations, soil and groundwater analysis, and hazardous building/structure material investigations. 

    The goal is direct: Provide each project’s design team with the environmental due diligence required to meet project-related goals, budgets, and schedules while maintaining the regulatory compliance and safety standards set for construction teams that include hundreds of dedicated people.

    Each project’s workforce is diverse and enormous. Each includes owner representation; city, state, and federal agencies; engineers; architects; surveyors; site planners; construction managers; tradesmen; and third-party suppliers. Internal communication and overall coordination relies on the individual skills, organization, and focus of one another to accomplish each task, while speaking in a technically proficient voice to a wide array of team members.

    Matrix personnel often work hundreds of feet below ground, as well as scouring (vacant or occupied) residential, industrial, or commercial structures — many older than 100 years — that have to be delicately demolished within an arm’s reach of local businesses and other residences. 

    Those structures not scheduled for demolition often require precise and complex modifications to existing structural, architectural, mechanical, electrical, and plumbing systems. This balancing act has to be accomplished without disruption to regular service (rail, commercial, or private), occupancy, or use.

    Such detailed work requires tremendous and ongoing communication and coordination within the team, including modifications to the investigation approach and work plans to allow each discipline, client, and local neighbor to co-exist.

    In addition, our work has to be done on a precise schedule, while ensuring the project scope complies with all applicable city, state, and federal guidelines.

    Much like the adage of “one weak link in the chain,” Matrix understands the importance of the environmental assessments conducted early in the preliminary design phase. Our conclusions and findings inherently have the potential to cause significant changes in scope, such as property acquisition, delays, and budget impacts.

    This ever-evolving urban construction environment presents many challenges that can be unforgiving if the project needs to be modified because of incomplete or inaccurate early information. Our work is conducted in full recognition of this fact, with the goal of lowering the risk for future surprises.

    Of course, no environmental assessment is complete without recognizing that previously unknown conditions may be uncovered during construction.  But that risk can be greatly minimized by exercising sound professional judgment and employing years of relevant experience.

    Moving forward into the next phases of these three projects, we know the continued success will not be possible without strong communication and coordination with each team member, as well as ongoing dialogue with affected neighbors and/or impacted parties.

    It is our sincere hope that the communication protocols we have established for these three urban transit projects — as well as other complex work that Matrix undertakes — can serve as a road map for other larger teams that embark on such major infrastructure projects.

    Gavin Gilmore is a senior project manager and Hazardous Material Group leader with Florham Park, N.J.-based Matrix New World Engineering, Land Surveying and Landscape Architecture, P.C. (www.matrixneworld.com), a full-service environmental, geotechnical, and civil engineering firm founded in 1990.