Crews build the temporary roadway in the I-78 median.
Konkus Corporation crews are pressing forward with the New Jersey Department of Transportation's (NJDOT) $27.9 million I-78 Bridges over Route 202/Route 206 and Washington Valley Road project, which began in mid-December 2019 and should be finished by the end of 2022.
The federally-funded project is replacing both eastbound and westbound decks, which have been deemed to be in poor condition. The work also includes bringing the existing guiderail up to current standards. The I-78 eastbound bridge over Route 202/206 is 125.2 ft. long and the westbound span is 129.5 ft. long, while the I-78 eastbound over Washington Valley Road is 202.75 ft. long and the westbound span is 204 ft. long.
"The existing span lengths and lanes will remain unchanged," said Brian Ahrens, an NJDOT public information officer. "The bridges over Route 202/206 will have four lanes in each direction. The eastbound bridge over Washington Valley Road will have four lanes, while the westbound bridge will have three. The original structures were built around 1965."
The four separate east-west bridges link the townships of Bedminster and Bridgewater in Somerset County.
"Two temporary bridges are being used in this project, which are still under construction," said Ahrens. "The temporary bridges will be spanning over Washington Valley Road and Route 202/206."
NJDOT planning for the project started April 2014 and design started August 2016.
"According to inspection report, the substructure — abutments and wing walls — and girders are in good condition," said Ahrens, "but the deck is in poor condition and needs to be replaced."
Based on data collected in 2018, total average daily traffic (ADT) consists of 108,000 cars and trucks, with trucks accounting for approximately 16 percent of ADT.
The project has been designed to advance in stages to minimize impact on motorists, beginning with the eastbound bridges. NJDOT's in-house Bridge Design Unit designed the re-decking.
"Building the temporary bridge required careful planning to avoid conflicts with underground utilities," said Ahrens. "A single span temporary structure was proposed to avoid the conflict with the underground utilities in the area. The scope of the project was to replace the decks, clean and paint the bearings, and repair the girders, and abutments. The new decks are expected to be in service for 20 to 30 years."
The decks will be cast-in-place.
So far Konkus is constructing the temporary bridges and once completed, traffic will be switched to them so that the re-decking operations can commence. The general contractor will have crews working during the winter months.
The temporary bridges are expected to be completed by late fall 2020 and will be in place for approximately two and a half years.
The use of cranes and Caterpillar excavators have been instrumental in the ongoing construction of the temporary bridges. The installation of the temporary roads has seen the use of rollers, loaders, a Cat mini-dozer, and a larger Cat dozer. Some of the lane construction is occurring between live traffic, with crews protected by concrete barrier.
Last January, crews had to do some milling and paving for the right lane and shoulder on I-78 westbound.
The westbound bridges will be re-decked first, followed by the eastbound bridges.
Temporary shielding will be used to prevent debris falling onto the roads below when the deck removal operations begin.
Peak days have seen close to 20 Konkus and subcontractor employees on site. Local and regional subcontractors have been brought on board.
The amounts of rebar, concrete, and asphalt recovered from the demolition of the old decks will only be tabulated once the removal operations are competed. Materials excavated from the bridges will not be recycled on-site.
New materials being brought in should tally approximately 3,000 cu. yds. of concrete and 800,000 lbs. of reinforcement will be used to replace deck and approach slabs for total four bridges.
Konkus and the subcontractors are and will be using: cranes, excavators, dozers, backhoes, rollers, pavers and other standard equipment.
Konkus purchases and rents equipment from local and regional dealerships.
NJDOT is on the midst of a major program to rebuild many aging bridges across the state as part of its initiative to replace aging infrastructure, and as pointed out, is receiving a fair amount of federal financial support to accomplish it. CEG