Experimental Study On I-section Beam-to-column Connections Under The Monotonic Load With Box Strengthen-joint Region And Expanded Flange In Weak Axis

After Kobe earthquake in Japan, lots of experts and scholars started to study on the steelframe to uncover damage of different tall steel structure under strong seismic action. Toreduce these influence under strong earthquake Japan proposed the extended flangeconnection.This paper combined with practical engineering examples designs the standered andexpanded flange beam-to-column connections in weak axis with reinforced boxstrengthen-joint region under monotonic vertical loading test, each kind of connectioncontains composite beam and non-composite beam. All the connections are bolted andwelded connection form. This paper detailly expounds the design and manufacture for thebeam-to-column connection, the detail structure form design, loading device and measuringtesting, experimental phenomena etc. In the detail structure form design, it elaborates thedesign idea and structure form for the triangular flange form, box strengthen-joint regionform and composite beam form. By observing the experimental process and measured data,we get the specimen in loading process of each part for the joints, the plastic hinge formingprocess and the key points strain changes, etc.Through dealing with the measured data, we get the P curve, M curve, ductilitycoefficient, stiffness and beam end plastic rotation and so on. The test results show that, allconnected nodes are greater than3in the displacement ductility coefficient,well the plasticrotation capacity can be more than0.03rad. Thus it shows that these connections have betterductility and plastic rotation capacity. At the moment rotation curve, expanded flange typenode is greater than standarded node in yield moment, but the ductility angle. In accordancewith the EC3standard at connection stiffness classification, expanded flange type node isgreater than standarded node, in supporting frame classification, expanded flange type nodebelongs to rigid nodes, in nonsupporting frame classification, expanded flange type nodebelongs to semi-rigid nodes. At the strain contrast key position, expanded flange type node can effectively force the plastic hinge, the forming position formed at the terminal expansionflange plastic hinge, meetting the design requirements.In the design of triangular expansion flange, through theoretical analysis, obtains the17.5%-25%short side for the beam flange width of the triangle side right angle side, at thesame time, the short side and the long side is controlled between1:4-1:3, the plastic hinge ofstress and the maximum stress ratio are ideal bending position and beam column butt weldjoints.