Plastic Bending of A514 Steel Beams

To determine how variations in the geometric ratios of b/t (the flange width is 2b) and L/ry affect the ability of A514-steel members to fulfill the requirements for plastic design, seven A514 steel I-shaped beams were tested in pure bending and two others were tested as centrally loaded beams in which the moment varied linearly from zero to maximum between bracing points. The moment-gradient and pure-bending tests simulated, respectively, first-forming and last-forming plastic hinges of frames. Both the pure-bending and moment-gradient tests indicated that A514 steel has sufficient rotation capacity for its use in plastically designed structures loaded in this way. The tests also indicated that premature plastic buckling of A514 steel I-shaped members will not occur if the value of b/t is limited to 5 and if the value of L/ry is limited to 21 for uniform-moment regions and 36 when the moment varies linearly from zero to maximum over the unbraced length.