BELLMAWR, N.J. (KYW Newsradio) — The section of wall that collapsed on I-295 in Bellmawr last year was the result of poor design and the wrong materials, according to a recent report. As such, engineering firm Hardesty & Hanover determined the wall never had a chance at success.
The retaining wall was a part of a $900 million project to connect Routes 295, 76 and 42. Before its collapse in March 2021, the project wasn’t expected to be finished until 2028.
The New Jersey Department of Transportation commissioned the report to determine the cause of the fall.
The main issue was an 8- to 19-foot-high layer of sand that was used as a base for a 29-foot high wall, labeled as Wall 22. The type of sand used — I-11 — was the wrong material for the job, as noted in the report.
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“Design mitigation measures would warrant implementation of either ground improvement techniques to improve in-situ soil’s strength and compressibility characteristics or the use of a different structural system to meet project performance requirements,” part of the report reads.
Beneath the thick layer of sand was a column-supported embankment system (CSES), and the analysts found that too was lacking in strength. It “experienced deformations outward toward the slope face,” engineers say.
In addition, the 29-foot wall was built in a location with chronic groundwater problems. The ground was saturated and the drainage system that was installed shifted, causing the base to give way horizontally and then collapse on March 25, 2021. The engineers say that the wall never had a chance to hold successfully.
Heavy rain the day before also exacerbated the wall failure.
During a site visit, the inspection team noticed significant erosion at the base of the wall.
The water problems, however, were not new. Forensic analysts found evidence of groundwater problems during the second phase of the construction.
There’s no official word yet on how long the collapse delayed the completion of Phase 3 of the project. Bids are currently being gathered for Phase 4.
KYW Newsradio requested an interview with New Jersey Department of Transportation Commissioner Dianne Gutierrez-Scaccetti. She was not available for comment.