(AP) – 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 in January 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 weathering steel. A new bridge at the site has since opened to traffic.