National September 11 Memorial
New York, NY

16 ACREs • WITH MICHAEL ARAD & PETER WALKER

To honor those who were killed in the terrorist attacks on September 11, 2001, the Lower Manhattan Development Corporation (LMDC) held a competition for the design of a memorial at the World Trade Center site. In 2004, the scheme “Reflecting Absence” by Michael Arad and Peter Walker was selected; and Davis Brody Bond was selected as the Associate Architect to execute the design of the Memorial Plaza. Our work on the Memorial shepherded this powerful design through numerous technical challenges. We applied our expertise to every aspect of the project, from the configuration of the bronze name parapets to the fountain geometry that creates the perfectly even waterfalls around the pools marking the absent towers. We were also responsible for coordination with adjacent projects, management of the diverse team of consultants, schedule, budget and delivery. Davis Brody Bond was later commissioned as the Design Architect for the Memorial Museum below the Memorial Plaza.

On the plaza, we collaborated on site fittings, materials, and lighting, and designed the mesh enclosures that integrate the large vent structures along the West Side Highway into the plaza. This program for these includes maintenance and storage workshop for grounds keeping equipment, Plaza security monitoring center, and security staff support spaces. It also provides a primary service entrance for the below grade spaces including the Memorial Museum, the Memorial mechanical spaces, and the World Trade Center site Central Chiller Plant. This entry point consists of security screening, staging area, and freight elevator access to all of the primary below-grade levels. In addition to the programmatic requirements, the structures also provide building egress from the below-grade occupied spaces and provide the for the technical requirements necessary for ventilating the 775,000 sf facility and meeting the stringent site wide security plan.

The geometry of the structures was driven by the need to meet the technical site security requirements while minimizing the visual presence of the structures on the Memorial. Rather than one large structure, the design separated the functions into two smaller structures. The prismatic geometries, deriving from the position and configuration of the ventilation ducts, further differentiate it from the orthogonal design of the Memorial. The concrete structures are shrouded in a woven metal fabric building skin.

  • Architect Handel Architects (Michael Arad)

    Landscape Architect Peter Walker Partners

    Structural Engineers WSP

    Geotechnical Consultant Langan

    MEP/Vertical Transportation Jaros Baum & Bolles

    Cost Estimation Faithful + Gould

    Geotechnical Engineers Mueser Rutledge Consulting Engineers

    Sustainability Consultant Viridian Energy & Environmental, LLC

    Lighting Designer Fisher Marantz Stone

    Acoustical, Vibration and Audio Visual Design Consultants Cerami

    Blast and Hardening Design Weidlinger

    Security Arup

  • Significant Consideration has been placed on the materiality of the project, ensuring an overall improved efficacy, quality of product and of experience. The extraction and manufacturing of materials used in the construction of the Memorial & Museum are limited within a 500 mile radius of the site, while fabrication regulations ensure major building construction systems (concrete, steel, etc.) include substantial recycled content. A minimum of 20% of all materials must be derived from renewable sources. Additionally, no low-emitting product may be selected, further maintaining air quality standards.

    The main Plaza level addresses several key environmental factors found in urban environments:

    • Storm Water Mitigation: Up to 350,000 gallons of precipitation, in the forms of snow and rain, are harvested through a combination of drainage and softscape systems, filtered, stored, and used in both the irrigation of the landscape and grey water plumbing. This drastically reduces the impact the site has on the city sewer systems and reduces the unnecessary use of potable water.

    • Heat Island Effect: Combating this effect created by extensive hardscaping, the project is seeking innovation credits for providing 100% shading (after 5 years) of these impervious surfaces through extensive tree planting.

    • Transportation: The design provides support for those who wish to use alternate transportation to get to the site. This includes bicycle racks for cyclers – as well as shower and changing facilities for employees who bicycle to work. Also, access to bus stops and terminals was included in the plaza planning to enhance the public transportation experience.

(Photography courtesy of Alan Ward, PWP, and N911MM)