SEISMIC MECHANISM OF STEEL MOMENT-RESISTING FRAMES WITH REINFORCED BEAM-COLUMN CONNECTIONS

摘要

Under intense earthquake loading,brittle failure usually happens in steel moment-resisting frames with traditional bolted-welded connections or full-welded connections. Then people are forced to make a new awareness of the seismic performance of steel structures. And new forms of rigid beam-column connections with good seismic behavior have to be explored. In this paper,several types of beam-column connections with local reinforcement are employed to improve the bearing capacity of nodes and to transfer the location of plastic hinges,which has been verified through low-cyclic reversed loading test. It is shown that the plastic hinge can be relocated effectively and the ductility of the node can be enhanced greatly,although the increase of the bearing capacity of the reinforced beam-column connection is not obvious under seismic loading. Therefore,energy dissipation capability of the node can be improved and brittle failure can be avoided in the node. Based on test results,deeply theoretical analysis of internal forces transmission,deformation development and the process of outward relocation of plastic hinge of the reinforced beam-column connections under seismic loading are carried out. Then seismic mechanism of reinforced beam-column connections is revealed.