Richard Clark, welder for Miscellaneous Metals Inc., welds a stair stringer to the header for a new staircase inside the William A. Jones III headquarters building Feb. 23, 2010 at Joint Base Andrews, Md. The stinger on a staircase carries the main load of the materials used for the stairs, as well as the weight of the 2,500 individuals who will use the stairs on a daily basis, after the building is completed next year. (U.S. Air Force photo by Airman 1st Class Perry Aston)