This challenging wharf rehabilitation was completed in only four months, on schedule, and within budget, while maintaining terminal operations.
Urban helped rehabilitate Penn Terminals’ 1,200-foot-long wharf along the Delaware River in Eddystone, PA, which was prone to sinkholes. The firm provided alternatives analysis, design, and construction management services.
Since its construction, the site was dredged to a layer of weathered rock, which exposed many of the sheet piles. A dive inspection revealed leaks through holes in the sheeting around the tidal zone, as well areas where sheet pile tips were exposed. The result was fill leaking from the bottoms of the cells.
After considering multiple alternatives to slow the loss of fill, Penn Terminals elected to reface the entire wharf from the mudline to the deck with a new wall. This project was challenging for several reasons. Layers of weathered and solid rock under the mudline at the face of the terminal made it nearly impossible to toe new sheeting to create a new bulkhead. In addition, terminal operations had to continue during construction — the terminal often serviced five vessels per week - and Penn Terminals wanted to complete the project in four months.
To address these challenges, Urban designed a combination of drilled steel pipe king piles connected by wide bays of flat steel sheet piles. The pipe piles were drilled into the solid rock to provide the lateral resistance at the toe needed when filling the void between the old and the new facing. Between the steel pipe piles, new sheeting was installed and toed into the rock at the mudline to seal the concrete poured between the two structures.
Through this innovative solution, the steel pipe and sheet piles served two purposes. They provided critical support during construction and composed the new wharf face. To minimize the size of the sheet piles and reduce costs, Urban specified use of lightweight concrete to fill the void between the two structures.
Urban also limited pour heights to avoid overstressing the piles. The firm staged construction to enable the terminal to maintain one berth open for vessel traffic. Even the longest vessels were able to use the open berth area.
Penn Terminals needed the entire terminal operational by December, when vessel traffic would increase for seasonal imports of fruits and vegetables. Owing to environmental restrictions on construction work, this left only three months to complete the project. The contractor and Urban’s construction management team worked long hours, logging double shifts and weekends, to complete the project on schedule and within budget.