Experimental Evaluation On The Behaviors Of Beam-To-Column Connections With Beam-End Horizontal Haunch

Steel moment-resisting frames were believed to be able to develop the strength and ductility required to resist strong seismic loading because steel is ductile. However, widespread and unpredicted brittle fractures have been found in weld steel beam-column connections (weld-flange-bolted-web connections) of moment-resisting frames shaken during the Northridge earthquake in 1994 and the Kobe earthquake in 1995. Such fractures were most often initiated at the bottom flange weld and propagated into the column flange and the beam web. The brittle failure prevents the welded moment connections from exhibiting the inelastic behaviour expected to resist earthquake loading. Since the Northridge earthquake, numerous experimental and analytical studies have been conducted to improve connection performance. The improvement is based mainly on strengthening the connection or weakening the beam to develop stable inelastic behaviour that will dissipate a large portion of the energy absorbed from the earthquake.The Beam-to-column connection with beam-end horizontal haunch is a kind of reinforced beam-to-column connections. It includes two categories of connections. One of the two categories is flange-widened connections. The other category is the side flange-reinforced connections. Though the side flange-reinforced connection has been mentioned, yet very limited test data are available. Four specimens were fabricated and tested to clarify the behaviour and failure mode of the connections with beam-end horizontal haunch under seismic loading. The main contests are listed as follows:Firstly, ampliative flange length was determined referring to reduced beam section connections which have had ripe theory. The nessesary width of reinforced flange was calculated on the basis of moving the location of the beam plastic hinge away from the face of the column to the narrowest section of the beam flange. Also, the decided flange-enlarged sections were proved to be appropriate by ansys ansysis.Secondly, hypocritical statics test about connections with beam-end...