On Monday, the National Transportation Safety Board (NTSB) released a preliminary report on the Fern Hollow Bridge collapse in Pittsburgh. The bridge collapsed around 6:45 a.m. on Jan. 28, and 10 people were injured.
The report states that the collapse began at the west end of the bridge, which ran along Forbes Avenue, one of Pittsburgh's most-traveled roads. It stretched over a ravine in Frick Park and underneath there was a trail and off-leash dog park.
The bridge connected the East End neighborhoods of Squirrel Hill on the west and Point Breeze on the east.
The Fern Hollow Bridge had a K-frame design. Each end rested on reinforced concrete caps on stone masonry abutments, and the girders were also supported by welded steel frame legs.
According to the report: "Although certain areas of the welded steel girders were identified as being fracture critical, no primary fractures were found in these areas."
The final report on the bridge collapse might take 18 months. The NTSB recovered video from a Port Authority bus that was headed east on the bridge when it collapsed. The bus had five interior cameras.
The NTSB has announced that its investigation will include a forensic examination of the bridge's structural components.
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SOURCE: National Transportation Safety Board
