Highways
Report Cites Multiple Issues in $900M NJ Interchange Wall Collapse
Work is set to start this summer to repair a 300-ft-long section of a 30-ft-high retaining wall that collapsed more than one year ago at a major New Jersey roadbuilding project—the already late-running effort called Direct Connection, which aims to untangle the convoluted interchange of north-south I-295, and east-west 1-76 and state Route 42 in Camden County, near Philadelphia. According to a forensic report made public last month by the NJ Dept. of Transportation only through a state Open Public Records Act request, problems existed in the wall built for a southbound I-295 ramp long before it crumbled in March 2021.
Overall Direct Connection construction began in 2013 and was extended to 2028 from 2024 even before the incident. The project had an original $900-million budget, with some reports now estimating it at $1.1 billion.
There were no injuries in the collapse, located in an unopened elevated part of I-295. The interchange is a key traffic flow link between Philadelphia and Atlantic City. and between Delaware and northern New Jersey and New York City.
An estimated 240,000 vehicles travel through the interchange area daily, according to the state DOT.
In a detailed analysis submitted under a $283,000 contract, engineer Hardesty & Hanover LLC, New York City, contends that signs of wall instability appeared in 2016. The firm says that “Wall 22” suffered a “complex failure” and displacement of “sandy fill soil used to build the embankment and slope underneath.” In February 2019, the analysis also says that work was interrupted for several weeks due to “observed distress” of several concrete panels making up the wall that were not meeting specifications of its supplier.
According to the report, sand and silt used were not appropriate materials to help support the wall due to “poor engineering properties at high moisture contents.” The site has a high groundwater level and was chronically damp.
The foundation of unreinforced concrete columns and a load-transfer mat made of steel mesh also “was not adequate to handle the weight pressing down on it or to withstand shearing” when the soil gave way, says the analysis, and that unreinforced concrete columns underground that supported the slope “were not adequate to withstand loads from the elevated roadway embankment and from the wall to provide a safe foundation.”
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Heavy rain on the day of collapse also “altered the marginally stable slope and ground improvement system [foundation] on which the wall was supported,” the report adds.
Going Forward
DOT spokesman Stephen Schapiro declined comment on an estimated repair cost or on liability issues for the state or for contractors, which he said were beyond the report's scope.
The contract for the portion of the project that included the collapsed wall, Contract 3, had been awarded to contractor South State Inc., Bridgeton, N.J. Design and construction companies involved in the work under that contract still are working, he said.
According to a report by nj.com, soils were tested by project design consultant Dewberry during subsurface investigations conducted, Schapiro said, with imported soil aggregate used in wall construction tested by the contractor and confirmed by NJDOT.
The new anticipated completion date of the current contract is to be determined, Schapiro said. The final contract, Contract 4, is set to begin after Contract 3 is completed and is expected to take four years.
U.S. Rep. Donald Norcross (D.-N.J.) and Camden County state legislator William F. Moen Jr. said they were told by NJDOT that the wall reconstruction would complete by summer 2023.
Still pending in the state Assembly's transportation committee is a bill introduced by Moen in May that would require stricter geotechnical monitoring for groundwater levels on this and other projects six months before work gets underway.
