After nearly a century of being battered by storms, tides and ships’ wakes, a portion of New Jersey’s Hudson River Waterfront Walkway gave way in June 2024. With a sudden whoosh, a large sinkhole opened on Frank Sinatra Drive in Hoboken, immediately bringing foot, bicycle and vehicle traffic to a halt on the busy thoroughfare. 

Hoboken is no stranger to sinkholes and other water-related infrastructure problems, both natural and man-made, and city officials immediately closed off the area to prevent further deterioration.

“With each tide cycle, water flows in and out, eating away at shoreline infrastructure,” said Lukman Osi, principal associate and bridges and structures department manager at Colliers Engineering & Design.

He would know. Osi has spent his career working on marine infrastructure projects, including helping New York City maintain its own 580 miles of waterfront.

Colliers Engineering & Design had completed another project for Hoboken, and the firm was on a shortlist of consultants officials had on speed dial. At 4:45 p.m. that Friday, Osi got a call from his firm’s national practice leader, instructing him to clear his weekend schedule.

“I was there an hour and 15 minutes later, after battling through rush-hour traffic, to assess the situation,” Osi said.

After securing the area to preserve safety, closing roads and ensuring surrounding structures weren’t at risk of collapse, Osi immediately started lining up his company’s practice teams to conduct an emergency investigation, and not just of the sinkhole but also of 777 linear feet of adjacent bulkhead.

The firm brought in its dive team and geotechnical boring specialists and pulled old reports to assess the condition of the sea wall, whose construction dated back to the early 1900s.

The sinkhole, 11 feet long, 20 inches high and 48 inches deep, was the localized evidence of failure. But the investigation found widespread erosion issues.

“It’s not a forgiving environment,” Osi said. “Steel corrodes. Concrete erodes and breaks apart. It quickly became clear that other areas were going to succumb. It was just a matter of time.”

While Colliers Engineering & Design executed the critical temporary repairs over subsequent weeks, the firm also presented the findings of its broader investigation to municipal officials. Large parts of the sea wall would need to be replaced rather than repaired, the firm’s study concluded.

Nobody Shuts Down Sinatra

While no one questioned the data outlining that a holistic rehabilitation project was needed, what made the project more challenging were the other constraints facing the city.

Sinatra Drive is a critical two-way traffic artery. Closing it completely for a long time was out of the question, as it would cause major congestion in Hoboken’s famously tight street grid.

“Shutting down a whole area would have caused ripple effects,” Osi said. “As part of our presentation, we needed to offer solutions and strategies that would help, but without crippling the city.”

Part of this strategy included anchoring a barge offshore as a staging area to keep one lane of Sinatra Drive open at least to one-way traffic.

But there were other challenges as well. The city had previously secured federal funds for a separate rehabilitation of Sinatra Drive itself, unrelated to the sea wall issues.

“Failing to break ground on that project on time risked having the city lose millions of dollars in funding for something that had been several years in the making,” Osi said.

Meanwhile, construction on the nearby Maritime Park skate park was set to kick off shortly. Delays in the sea wall rehabilitation project would hamper that project as well, a situation the city was keen to avoid.

Plus, there were other stakeholders and priorities to consider. The walkway is a beloved amenity that passes through not just Hoboken but also eight other New Jersey towns: Bayonne, Jersey City, Weehawken, West New York, Guttenberg, North Bergen, Edgewater and Fort Lee.

Residents of those towns cared about what was happening in Hoboken, Osi said.

Finally, New York and New Jersey were preparing to host FIFA World Cup games in 2026. Hoboken needed to put its best foot forward during the monthlong event, for both its own residents and soccer fans visiting from all over the world.

Long-Term Solution

“We knew maintaining the project schedule would be paramount,” Osi said. “Having all the services we needed right at our fingertips from a single source created a more efficient and coordinated process throughout the entire project.”

Colliers Engineering & Design deployed the full breadth of its multidisciplinary capabilities to address the city’s requirements and get the work done, he said.

“Our traffic experts were able to conduct traffic studies and make recommendations on alternative routes,” Osi said. “Our survey team located existing utility lines so we could protect them. Our geotechnical team did borings, our GPR team did the scan, and our construction, engineering and inspection team was on-site throughout.”

Despite the accelerated time frame to find an available construction firm for this emergency project, Colliers Engineering & Design still solicited offers from a handful of chosen construction firms. It chose the lowest bid, saving the city of Hoboken money.

Another way the firm saved time and money was by instructing all teams, including the divers, to collect backup data whenever they were on-site to be as efficient as possible and not add to disruptions, Osi said.

Ultimately, Colliers Engineering & Design presented city officials with a proposed design solution that was innovative by necessity and would get the job done for the long term.

“We found we couldn’t just replace what had been there because the same problem would recur,” Osi said. “There isn’t adequate soil there, and the undulating bedrock is shallow. You can’t just put a foundation on top of it.”

Instead, the firm had to come up with a sea wall replacement design that could be anchored into the bedrock. Colliers’ solution was to core 24-inch-diameter steel piles into the bedrock and anchor them using specialized machinery, treating the bedrock like a concrete base. 

The rock-socketed piles system also included interlocking sheet piles that created a continuous structural barrier along the shoreline. The design ensured the sea wall would be resilient not just to today’s storm and wave conditions but also to more extreme marine conditions in the future, he said.

Now complete and largely hidden beneath the waterline, the system is essentially the structural backbone that made possible more visible improvements to the walkway public space. These include a rebuilt pedestrian surface of new precast concrete planks, rehabilitation of the walkway’s offshore platform and restoration of the promenade’s pavers.

Hoboken’s Frank Sinatra Drive has been restored. The walkway now meets Americans with Disabilities Act accessibility standards. New lighting has been installed, and benches, railings and water fountains have been reinstalled. The rehabilitation project also ensures this beloved stretch of shoreline is a safe place for Hoboken residents and visitors to enjoy for decades to come.

“They don’t have to worry about it for a very long time,” Osi said.

This article was produced in collaboration between Colliers Engineering & Design and Studio B. Bisnow news staff was not involved in the production of this content.

Studio B is Bisnow’s in-house content and design studio. To learn more about how Studio B can help your team, reach out to studio@bisnow.com.