Bending huge steel girders. Washington, D.C., Sept. 23. At the U.S. Bureau of Standards officials were witnessing the testing of rigid steel frame knees that are used in grade eliminations such as over-passes, under-passes, bridges, etc. This photo shows the girder or knee placed into the huge 600,0

Harris & Ewing · 1937-01-01 · photo, print, drawing

From the collection of Library of Congress. Free to download, adapt and use — no permission needed.