The Fern Hollow Bridge collapse threw off the lives of many Pittsburgh residents, cutting off a main artery in the city. A year after the collapse, federal investigators at the National Transportation Safety Board (NTSB) released their probe into the destruction, yet no conclusion was found on why the structure fell a year ago.
The NTSB records included information of prior work and weather studies on the day the Fern Hollow Bridge collapsed.
The report that was released Thursday took note that experts found multiple fractures on the legs of the structure. They had been deteriorating for years, while being in poor condition since 2011. According to the report, a lab in Virginia is running tests that are almost complete, and results will be compared to “specifications referenced in the bridge’s original design plans.”
Over 2,000 records show that the structure had three-dimensional scans performed to it, while investigators carried out mechanical and metallurgical testing of pieces that were gathered after the collapse.
In December, the new Fern Hollow Bridge opened. However, there are still questions that many have.
Hota GangaRao, an engineering professor at West Virginia University, said in an interview last year, “There’s no question in my mind that [the city] dropped the ball and refused to invest money in maintenance on this bridge and that led to its failure.”
Agents at the NTSB interviewed personnel from the city of Pittsburgh, PennDOT and consultant firms involved in the maintenance and inspection of the bridge. The information from those interviews will be added to the docket at a later time.
According to the report, investigators also carried out inspections of 10 steel frame bridges in the state with design elements similar to Fern Hollow’s K-frame, however it had no conclusions.
According to Pittsburgh's Post-Gazette, the city had been warned about the deterioration and the durability of the span since 2007.
The Post-Gazette was told by experts after the city propped up the structure with cables that this solution was inadequate for a structure of its size.
The NTSB said it "continues to identify and collect documents from the City of Pittsburgh, PennDOT, and various contractors. The documents provide information about the Fern Hollow Bridge design, maintenance, and inspections,” according to the report.
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Source: The Post-Gazette
