Investigators vow to put collapsed bridge under ‘microscope’

PITTSBURGH (AP) — Federal investigators are vowing to put a collapsed bridge in a Pittsburgh park “under a microscope” as they examine evidence. That includes 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. Officials said 10 people, including some first responders, were evaluated and treated for minor injuries Friday morning, and three people were taken to local hospitals with non-life-threatening injuries. Federal officials on Saturday said they would examine the bridge’s “entire history” from design and construction, to maintenance and repair and all work up until the day of the collapse.