The Slurry Wall: Past, Present, and Future

ABSTRACT

One of the most telling artifacts in the 9/11 Memorial Museum is the slurry wall, a vestige in situ of the pre-9/11 World Trade Center complex, preserved under Section 106 of the National Historic Preservation Act. This subterranean 20 meter long section of the perimeter wall that surrounded 4.5 hectares of the Trade Center site was never meant to be seen or tell its story. Made of reinforced concrete,and tied back to bedrock, its job was to hold back the waters of the Hudson River. The wall was a marvel of engineering in its time and on 11 September 2001 withstood untold forces and thus acquired new meaning – the once mute, utilitarian object became a symbol of hope and resilience. The slurry wall no longer performs the work it was intended to – there is another loadbearing structure behind it – but remains in conversation with Mother Nature. The wall weeps, which has catalyzed corrosion of the steel, introduced salts and a host of other material concerns. The complexity of the slurry wall, as an artifact and an architectural element of the Museum that affects its environment, has necessitated collaboration between a diverse group of stakeholders to parse its secrets.

KEYWORDS:

• Concrete
• steel
• World Trade Center
• Hudson River
• non-destructive evaluation
• preventive conservation
• slurry wall

Acknowledgements

Our first thanks extend to American Express who made the study of the slurry wall possible. At the 9/11 Memorial & Museum, a special acknowledgement goes to Dr Jan Seidler Ramirez and we also thank Anthony Gardner, Alice Greenwald, and Amy Weinstein. We are indebted to many colleagues who facilitated and furthered our research including Peg Breen, Steven Davis, David Dunlap, Daniel Libeskind, Ken Lustbader, Charles Maikish, Andrew Pontecorvo, Peter Rinaldi, Nathaniel Smith, and George Tamaro. We also thank Matthew Bushell, David Flory, Kacey Hadick, Scott Lee, Catherine Matsen, Brian Pailes, Kara Parker, John Ristevski, Paul Schmall, John J. Walsh, and Anna Weiss-Pfau, who provided great expertise with analysis, imaging, and survey work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Notes

1 Short documentary by Conte, L, J. Graham-Felsen, (producers) and S. Zehentner (director). 2019. Memory Foundations: The Story of the Slurry Wall . USA, Steve Zehentner Productions.

2 Simpson, Gumpertz and Heger Inc. 2005. Slurry Wall Testing and Inspection, Memorial Museum at the World Trade Center Site, NY. Unpublished report.

3 See note 2.

4 Davis Brody Bond with Mueser Rutledge Civil Engineers, WJE Engineers and Architects, SGH Consulting Engineers, JBB Consulting Engineers. 2013. National September 11 Memorial and Museum Liner and Slurry Wall Leakage. Unpublished report.

5 15th Anniversary of 9/11: Sealing The Bathtub - No Small Project. 2016. Underground Construction 71(9). Retrieved from https://ucononline.com/magazine/2016/september-2016-vol-71-no-9/rehabilitation/15th-anniversary-of-911-sealing-the-bathtub-no-small-project.

6 Painted steel covers where the liner walls meet the slurry wall, added for aesthetic reasons prior to the opening of the Museum, make the areas most affected by water penetration inaccessible. In 2019, the conservation team added small hinged doors to provide access. Blockages have since been cleared and drainage is being monitored.