To minimize disruption to traffic and reduce construction cost by up to $50 million, the authority chose to take "a unique overall approach to utilizing partial depth replacement of more than 30 years to get the same benefits as a full-depth deck replacement” of more than 550,000 sq ft of roadway deck using conventional hydro demolition and high-performance concrete deck replacement methods, says Debra Moolin, RITBA project manager. The original deck is a 7.5 -in.-thick reinforced concrete deck with integral wearing surface, she added. 

Performing a partial-depth deck replacement on an original 50-year deck gains a similar service life as a whole-depth deck replacement for one third of the cost, she says. “This approach to prolonging the service life of the original deck, to my knowledge, has not been implemented on any other large, complex, long span bridge."

The intent is to minimize the effects to traffic and construction costs by several orders of magnitude through planned maintenance and repairs to contain deck deterioration within the top half of the deck and to perform partial depth deck replacement instead of full depth replacement providing a minimum 30-year service life of the rehabilitated deck. 

“Full depth deck replacement for this 550,000 sq ft in a marine environment with approximately 60% of the length of structure over 80 ft above water brings significant effects to traffic and significant construction cost,” Moolin said, “The issue was identified by the RITBA as a key issue during long-term planning over 30 years ago.” 

All four lanes reopened to traffic on Nov. 19, with the four-phase project that began in November 2019 slated to finish on schedule by May 2021. “It was a tough schedule to maintain while minimizing traffic interruptions on the bridge,” says Bob Smith, a project manager for the project’s Warwick, R.I.-based contractor, Aetna Bridge Co. The design-bid-build contract for the Pell Bridge deck rehabilitation project includes liquidated damages of $5,000 per day for late completion and incentives of up to $10,000 per week for early completion of one milestone once the project is complete, adds RITBA's Seabury.

Phase three began in March following a month-early completion of phase two hydro demolition, and involved a partial-depth hydro-demolition and reconstruction of the concrete bridge deck for 4,700 ft of the westbound and eastbound lanes. Aetna removed the bridge deck down to the first layer of steel rebar, performed steel and joint repairs and placed new concrete, which required long-term lane closures until the recent reopening, according to the authority.

“The most difficult thing with hydro demolition and concrete overlay was working in narrow work zones while keeping the traffic moving, since we had heavy equipment,” says Jeff Bostock, vice president, construction at Aetna.

The team employed contraflow traffic controls while replacing concrete on single lanes of the deck and conducting full-depth demolition and replacement of reinforced concrete joint headers and installation of new joint seals at some piers.

Moolin says the authority is now completing the third of five planned partial depth deck rehabilitation programs. “At the completion of this contract, half of the structure will have rehabilitated deck,” she says. “Of the remaining deck, half of it is in good condition and anticipated to be able to be maintained with repairs and sealing only for another ten years, and half is scheduled for partial depth replacement in the next five years."

RITBA coordinated with the Rhode Island Dept. of Transportation to complete deck work on the east approach of the Newport Bridge so that the RIDOT can break ground on the $56.4-million Newport Pell Bridge Approaches project in the spring, Seabury says.