Empty Sky 9-11 Memorial Liberty State Park

The State of New Jersey retained GZA to design repairs to the bulkhead along the Hudson River and the Liberty Walkway at the New Jersey Empty Sky Memorial. The walls of this symbolic structure, lined with the names of the 749 New Jersey residents who were killed in the 9-11 terrorist attacks, channel visitors’ views across the Hudson River to Ground Zero in Lower Manhattan.

Challenge

After the project started, it was decided that all work – from investigation through design, permitting, bidding, and construction – had to be completed in advance of the 20th anniversary of 9-11, which was only about 12 months away. The ambitious project schedule was made even more challenging when additional repairs were requested to drainage and landscaped areas around the memorial.

Solution

The subsidence of the walkway was due to failure of the existing steel sheetpile bulkhead; GZA designed a replacement bulkhead that significantly reduced the level of effort for the repair work and minimized disturbance to the area. But during the bid phase, serious concerns were raised regarding the ability to complete the work in time for the high-profile anniversary date because of the lack of remaining float in the project schedule to compensate for possible material delivery delays or weather delays. Therefore, GZA’s water resources engineers designed an innovative and practical interim solution for the walkway repair as a first phase, with the full-scale replacement to be completed after the 20th anniversary ceremony on 9/11/2021.

The additional work to the area included repairing the drainage system surrounding the memorial and various hardscape features near the memorial.

Benefit

The GZA engineers’ proven track record as effective and innovative problem solvers gave the state agency in charge of the project the confidence to entrust the high-profile work to GZA.