FILE—This is a Pittsburgh Transit Authority bus that was on the Fern Hollow Bridge in Pittsburgh when it collapsed in this file photo from Jan. 28, 2022. Investigators looking into the collapse of the Pittsburgh bridge last year want transportation officials nationwide to closely examine more than 10,000 other bridges with similar construction to make sure they don’t have the same kind of corrosion that was found on the bridge that collapsed. (AP Photo/Gene J. Puskar, File)

Federal investigators say the city of Pittsburgh did not adequately maintain or repair a bridge, leading to the corrosion of the structure’s steel legs and its collapse into a ravine more than two years ago. The city-owned Forbes Avenue bridge fell down on Jan. 28, 2022, plunging a bus and four cars about 100 feet into the Fern Hollow Creek. Another vehicle drove off the east bridge abutment and landed on its roof. National Transportation Safety Board investigators said Wednesday that the collapse shouldn’t have happened, blaming “repeated failures to act” on extensive corrosion to the uncoated weathering steel. A new bridge at the site opened to traffic in December 2022.