| Beam-to-column connection is an important and complicated content in the steel frame design. The reliability of connections has much important influence on the behavior of whole steel fame. Traditions, it was regarded that steel frames with welded beam-to-column connections had excellent performance, so it were widely adopted in steel constructions. During the North ridge earthquake in 1994 and Kobe earthquake in 1995, a large number of steel Moment-Resisting Fames experienced brittle fractures at beam-to-column connections. The new-type connections and semi-rigid connection have becoming the hot research subjects gradually in recent years. Domestic and foreign scholars in the study of steel beam-column joints improvements focused on the following aspects:1) scallop structure improvements;2) the processing beam flange weld backing notch effects;3) Node plastic hinge shifting.Based on the requirements of the above kinds of nodes improvement measures, while meeting the earthquake, we can improvements be broadly divided into two types of enhanced node and enhanced node. Enhanced node means by weakening the beams so that the appropriate parts of the beams at the time of earthquake generated first plastic hinge, so that the node shaping performance into full play, to better seismic energy consumption, beam-column joints to prevent brittle failure. Methods based on the previous research results, drawing some scholars, the method of non-linear finite element analysis on the formation mechanism of Steel Frame semi-rigid plastic hinge connecting nodes were analyzed and studied systematically.First, according to the steel frame "strong column-weak beam" seismic design principles, this paper chose the semi-rigid bolted and welded hybrid node as the object of study, the use of finite element software ANSYS Workbench 15.0, according to the effective control of the beam plastic hinge position basic ideas presented in the form of nodes on beam web opening, opening web analysis weakened radius node and weaken the influence of the distance of the nodes produce plastic hinge location and node bearing capacity. Secondly, we study the stress distribution at the beam web openings weaken revealed microscopic reasons for the relocation of the plastic hinge location. Based on the results given value formula beam web openings weakened form of the two main parameters for the design and construction of steel framework beam semi-rigid beam-column joints provide good advice. |
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