On Thursday, the National Transportation Safety Board (NTSB) released an update on its investigation into the Fern Hollow Bridge collapse. The bridge experienced a structural failure when the 447-foot span fell 100 feet into Frick Park on Jan. 28, injuring nine people. Video images from two cameras on the Port Authority bus involved have provided authorities with more information.
The forward-facing camera shows the bridge deck separating at the east expansion joint, with the curbside camera also capturing the separation at nearly the same time. The west end of the bridge had already fallen off the west abutment, the updated report said.
Even with the new information on the timeline of the collapse, the NTSB said there's still no evidence of widespread deficiencies with rigid K-frame superstructure types.
The Federal Highway Administration is also helping with the investigation, giving the NTSB resources to evaluate the materials used in building the bridge. The two agencies will work together to perform mechanical and chemical testing on samples from parts of each bridge leg and girder sections.
The NTSB is still investigating the collapse, and hopes to eventually issue safety recommendations to prevent similar events.
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Sources: CBS Pittsburgh, NTSB
