EXPERIMENTAL STUDY ON MECHANICS PROPERTY OF FLANGE PLATE-REINFORCED CONNECTIONS OF STEEL FRAMES

The plate reinforced connection is a type of improved beam-column anti-seismic connections, which includes a flange-plate reinforced connection and a cover-plate reinforced connection. In order to study the ductility and aseismic performance of this connection forms, four beam-column T-joints of a steel moment-resisting frame were designed at 1/2 scale. There were two flange-plate reinforced connection specimens and two cover-plate reinforced connection specimens. The failure modes, the hysteresis curve, the curve skeleton, the ultimate load, the maximum plastic rotation, and the ductility performance under a cyclic loading were studied. As compared, one ordinary connection specimen was tested. The results indicate that there is an expanded plastic hinge zone which was formed at the outside of the flange-plate by setting a flange reinforced plate to a beam-end reinforced connection, which could consume the most energy and avoid premature brittle failure at the weld between the beam and column due to the development of the beam-end stress. Compared with the traditional connections, the plastic deformation capacity and energy capacity of the reinforced connection are better, thusly this connection is an ideal ductile node. The results also showed that the bearing capacity of the specimens could be improved, consequently the bearing capacity improvement of the specimens should be considered in aseismic design. Moreover, the design steps of the connections have been given, which offered references for the corresponding engineering design of the connections.