Fallen bridge to go under official ‘microscope’
PITTSBURGH — Federal investigators on Saturday vowed to put a collapsed bridge in a Pittsburgh park “under a microscope” as they examine evidence, including video from a municipal bus that plummeted along the span, prompting rescuers to rappel down a ravine and form a human chain to reach a few occupants.
Five vehicles were on the bridge along with the bus at the time of Friday’s predawn collapse in Frick Park. City officials said 10 people, including some first responders, were evaluated and treated for minor injuries, and three people were taken to local hospitals with injuries that were not life-threatening. The collapse ruptured gas lines that ran along the bridge, causing a large gas leak and the subsequent evacuation of several families from their homes.
Jennifer Homendy, chair of the National Transportation Safety Board, said Saturday evening that investigators over the coming weeks would “put this bridge under a microscope,” looking at its “entire history” from design and construction, to maintenance and repair and all work up until the day of the collapse.
A crash reconstructionist on Saturday used a drone to map the scene and investigators made an initial inspection of the structure and the legs under the deck of the bridge, looking for signs of corrosion and fatigue cracking and also wanting to see how the structure came to rest. Investigators were also trying to identify areas for closer inspection and may want to take pieces back for laboratory analysis, she said.
Dennis Collins, investigator in charge, said structural engineers will be looking at every component of the bridge in methodical fashion, from supports to truss work to joints to the road structure itself.