National September 11 Memorial Museum
New York, NY

110,000 SF • 10,220 SQ M

The 9/11 Memorial Museum was conceived as the global focal point for presenting and preserving the history and memories of the events of 9/11, documenting the impact of the attacks and exploring their enduring significance. The Museum is located beneath the 9/11 Memorial at the World Trade Center.

Descending nearly 70 feet to the original footprint of the World Trade Center towers, its 110,000 sf interior gives visitors access to the monumental underground site where remnants of the Trade Center’s construction and recovery frame the story of the terrorist attacks and the days that followed. Confronting the physical void left at the end of the recovery process, the spaces of the museum are revealed, progressively disclosing the various elements of collective and personal memory of the event.

Given a fixed set of existing geometries at the site, we were faced with the challenge of translating them into a series of coherent spaces that are punctuated by surface, texture and volume. We chose as the space’s main narrative element a gently descending procession (dubbed “the Ribbon”) that guides visitors from the plaza to the bedrock level where the cut columns of the World Trade Center towers are revealed. The ribbon evokes the ramp used to remove debris from the site in the aftermath of the attacks. It also offers multiple views of the slurry wall, the original retaining wall that was built to withstand the lateral forces of landfill and river, and which survived the collapse of the towers. At the end of the ribbon, the descent continues down along the Vesey Street Stair (“Survivors’ Stair”), which was used by hundreds to escape to safety on 9/11. It ultimately leads to two exhibition spaces and Foundation Hall, the Museum’s culminating space whose sheer scale conveys a sense of the enormity of the site and reinforces awareness of the absence of what once was there.

Davis Brody Bond had a dual role on the site as Design Architect for the Memorial Museum and as Associate Architect (with Peter Walker and Michael Arad) for the Memorial Plaza. The Museum was dedicated by President Barack Obama on May 15, 2014 and opened to the public on May 21, 2014.

(Photography by James Ewing; B&W photography by Andrew Moore)

  • Concept
    The design of the 9/11 Memorial Museum creates a visitor experience which is deeply intertwined with the cultural memory and emotional reaction to the events and site of September 11, 2001. The architecture and materials of the museum are used to enhance this visitor experience and articulate four core design principles: Memory, Authenticity, Scale and Emotion. Concrete, some raw and some polished, is the predominant material of the floor and walls that survived within the 70 feet deep excavation of the remediated World Trade Center site. Within this excavation are two new insertions the Tower Volumes and the Ribbon. The Tower Volumes align with the footprints of the original Twin Towers and the pools above, creating sense of context and connection to the site. The Ribbon provides a gently ramped descent whose faceted form winds between the Tower Volumes and brings visitors to the bedrock level.

    The decision to locate this museum at the site of the event it interprets differentiates the Memorial Museum from most other museums and provides an important link between the act of memorializing those who perished and the provision of a narrative historical account of the event.

    Program
    The 9/11 Memorial Museum, set within the preserved foundations of the Twin Towers, was charged with telling the stories of individuals and communities affected by the events of the day. The international audience served by this museum varies greatly in age and knowledge of the attacks, while our understanding of that day and its aftermath continues to evolve, as well. Recognizing the need to find a universal means of communication to a diverse audience, the design empowers visitors to connect to their own memories and experiences through a gradual and carefully sequenced descent to bedrock.

    Zoning Characteristics / Constraints
    The site dictates the museum’s building envelope, which is physically bound by the PATH station, the various construction efforts of the WTC as well as the 60 ft high original slurry wall that withstood enormous lateral pressures from the surrounding area after the collapse.

    The publicly accessible footprint of the museum is about 1/3 of the total project area, while the remaining 2/3 of the site (part of the museum construction effort) provides the civil infrastructure to support the full future redevelopment of the WTC site, including an electrical sub-station for the full site, a utility plant to provide heating and cooling for the full redevelopment (12.5M sf of the WTC, the Memorial and Museum plus the PATH station and smoke evacuation of the subway tunnels under the Hudson River). The project also includes a single service access point for the entire redeveloped WTC. The five future towers, the Memorial and Museum and the transit hub are all serviced.

    Construction Systems
    To emphasize the preservation the authentic site, the existing artifacts (tower column footprints, Slurry Wall and exposed foundations) were left in their raw state juxtaposed to the inserted architecture which was given a polished, refined finish. The 9/11 Memorial Museum incorporates many diverse uses of cast in place concrete: the mass concrete placement of the 4’ thick liner walls; the 2’ thick cast in place shear walls, which provide lateral stability to the buildings subsurface structure; the 3’ wide by 7’ long by 70’ deep concrete counter forts; and the polished concrete floors. As stated, these concrete elements were designed and installed with a sensitivity to the existing exposed concrete remnants to help tell a part of the story of the events of September 11 and the rebuilding of the site. Intricate detailing was required between newly placed concrete and adjoining artifact concrete of the original twin tower slabs and footings. All this was done while working with the structural durability that concrete provides to fulfill many unique safety and blast requirements posed at the site. The cast in place concrete not only makes up the structure of the edifice but helps to form the pages of the story being told throughout the museum.

    Mechanical Systems
    A major concern in the museum was the environmental separation between the permanent exhibit galleries (within the Tower Volumes) which required traditional, humidity controlled environments and the open hall spaces that make up the majority of the museum (Foundation and Memorial Hall, and the Ribbon descent) which did not require the same level of environmental controls. The permanent exhibit galleries were sealed off from the rest of the museum, employing revolving doors to limit air flow exchange and creating a separate climate controlled environment. The memorial fountain above further complicated the climate controls, with the lower catch basin above falling directly above the exhibit galleries. Beyond waterproofing and vapor barriers, the distance between the exterior and interior were so slim additional spray insulation was used between layers to ensure no thermal transfer would occur.

  • Architecture and Planning
    Davis Brody Bond
    Steven M. Davis, FAIA, Partner
    Carl F. Krebs, FAIA, Partner
    Mark Wagner, AIA, Project Director

    Consultant Team
    Structural Engineering WSP Cantor Seinuk
    Structural Engineering, Slurry Wall Guy Nordenson and Associates; Simpson Gumpertz & Heger, Inc.
    Blast Design Weidlinger Associates Consulting Engineers
    MEP Engineering/Vertical Transportation Jaros Baum & Bolles
    Lighting Designer Fisher Marantz Stone
    Geotechnical Engineering Langan Engineering & Environmental Services
    Geotechnical Engineers, Slurry Wall Mueser Rutledge Consulting Engineers
    Code Consulting Code Consultants Inc.
    Acoustical and Vibration Design Cerami & Associates, Inc.
    Graphics C&G Partners
    Historic Preservation Higgins & Quasebarth
    Security Design ARUP
    Sustainability Consultant Viridian Energy & Environmental, LLC
    Building Envelope and Waterproofing Wiss Janey Elstner, Associates
    Specifications Construction Specifications, Inc.
    Cost Estimating Faithful + Gould

    Contractors
    Port Authority of New York and New Jersey
    Bovis Lend Lease

  • 10 Historic Preservation Groups
    NYC Landmarks Preservation Commission
    National Trust for Historic Preservation
    NY SHPO
    Municipal Art Society
    New York Landmarks Conservancy

    10 Planning Advisory Groups
    American Planning Association NY Chapter
    American Institute of Architects NY Chapter
    NYC Department of City Planning
    Regional Plan Association
    NYS Department of Transportation

    15 Neighborhood Associations and Institutions
    Hudson River Park Trust
    Battery Park City Authority
    Battery Park City United
    WTC Residents Coalition
    Lower Manhattan Cultural Council
    St Peter’s Church
    Pace University

    8 Government Representatives
    NY Mayor’s Office
    NY Governor’s Office
    US Senator Corzine
    US Representative Maloney and Nadler
    City Councilman Gerson
    State Assembly Speaker Silver
    State Senator Connor
    Port Authority of NY and NJ

    10 Family and Survivor Groups
    9/11 Widows and Victims Family Association
    WTC Families for a Proper Burial
    Voices of September 11th
    Coalition of 9/11 Families
    Cantor Fitzgerald Relief Fund
    Families of September 11th

  • Size
    Museum Total: 268,000 sf (of which 110,000 sf is publicly accessible)
    Chiller Plant: 163,000 sf
    Memorial Total: 344,000 sf
    Project Total: 775,000 sf
    Number of floors: 3 (2 publicly accessible floors: Concourse Level and Bedrock Level, 1 Intermediate Fountain and Museum Support Floor)
    Occupancy: 2,500 visitors

    Schedule
    Opening Date: May 21, 2014
    Design Dates: 12/01/2004 – 2013
    Construction Dates: 01/2008 – 05/2014

    Role & Scope
    Design Architect, Full A/E Services

    Sustainability
    LEED Gold

    Client
    National September 11 Memorial & Museum at the World Trade Center Foundation

  • Awards
    2015 National AIA Honor Award for Interior
    2015 Honor Award for Architecture, AIA
    2015 American Architecture Award, Chicago Athenaeum
    2015 The Gold Award of Excellence, Society of American Registered Architects, NY Council
    2014 Best of the Year Awards, Winner, Museum/ Gallery Category, Interior Design Magazine

    Publications
    The New York Times, “The 9/11 Story Told at Bedrock, Powerful as a Punch to the Gut,” Holland Cotter, May 14, 2014
    The New York Times, “In 9/11 Museum to Open Next Spring, Vastness and Serenity, and Awe and Grief,” David W. Dunlap, June 28, 2013
    Architectural Record, “National September 11 Memorial & Museum: Creating a Place to Honor the Past and Look Ahead,” Clifford A. Pearson, September 2011

Survivors’ Stairs
Visitors descend to the Museum’s bedrock level alongside the Vesey Street Stair remnant known as the “Survivors’ Stairs,” which were used by hundreds to escape to safety on September 11th.

Project Context
The project needed to consider and accommodate a program specific not only to the museum but also to adjacent projects, which at various stages during design would influence and impact the development of the museum. These adjacent projects included: the 9/11 Memorial, the PATH station and transportation hub/commuter transportation, the Central Chiller Plant (serving all buildings on the redeveloped WTC site), site-wide security measures and design needs, and the secure vehicular access for site-wide loading and servicing.