Experimental Behavior of Stiffened and Unstiffened End-Plate Connections under Cyclic Loading

To compare the hysteretic behavior, stiffness, and strength of stiffened and unstiffened extended end-plate connections of beam–column joints, six specimens with eight high strength bolts were tested under cyclic load. During the test, the axial force of the column was kept constant. The end plates of three specimens and column webs of five specimens were reinforced with rib stiffeners, and the thickness of end plates was varied with the same configuration of beams and columns of all the specimens. Although the plastic rotation of all connections exceeded 0.03rad, they showed different hysteretic behavior, the stiffened ones exhibited higher load carrying and energy dissipation capacities, and the end-plates’ stiffness had a crucial influence on their cyclic behaviors. For thinner end plates, stiffeners can increase the stiffness of the connection greatly, and delay the premature fracture of welds. Stiffeners of the column web can change the stress dissipation panel zone and reduce the possibility of strength failure of column flange.