A bridge in Pittsburgh collapsed on Friday hours before US President Joe Biden was due to arrive in the former steel city to highlight his efforts to strengthen the country’s infrastructure.Ten people sustained injuries, all of them minor, when the snow-covered span in the northeastern state of Pennsylvania collapsed into a wooded gully at about 6am, according to authorities, who said a massive gas leak was reported in the area at the time. The leak was brought under control, they said.The two…