A section of a bridge collapsed onto an expressway in Oklahoma City Thursday after it was struck by a semi-truck, officials said. Police told Fox 25 a flatbed semi-truck driving on the Northwest Expressway carrying a "boom lift" struck a portion of the May Avenue bridge, causing it to collapse. Video from the scene showed the semi-truck trapped under the debris, but police said the driver was not injured. "A semi made contact with the bridge and it collapsed — we’re not sure what the cause of him crashing into the bridge was," Oklahoma City police Sgt. Ashley Peters said.