The National Transportation Safety Board published an investigative update​ and released new factual information via the public docket for the Jan. 28, 2022, Fern Hollow bridge collapse in Pittsburgh.

The 447-foot-long bridge experienced a structural failure and fell approximately 100 feet into the park below. Six vehicles were on or near the bridge when it collapsed, according to the NTSB.

As part of the investigative update, the NTSB noted that engineers from its materials laboratory have analyzed portions of the bridge’s legs with 3D technology and metallurgical testing. Investigators have also interviewed personnel involved in the maintenance and oversight of the bridge and examined other bridges within Pennsylvania’s inventory having similar construction features.

The docket made public on the NTSB’s website contains 2,137 pages of factual information covering various aspects of the investigation and includes preliminary reports, documents pertaining to the materials and construction specifications of the bridge, maintenance records, and manuals addressing bridge management and inspections within the state of Pennsylvania. 

The docket contains only factual information collected by NTSB investigators; no conclusions about the probable cause of the collapse should be drawn from the information within the docket. Analysis, findings, recommendations, and probable cause determinations related to the collapse will be issued by the NTSB in a final report at a later date.