Mechanical Study Of Steel Frame Flange-Plate Reinforced Joints At Beam-End

Flange-plate reinforced connection is a typical flange-reinforced connection.By welding flange-plate,section modulus has been improved, plastic hinge be formed some distance from the end of beam,and achieve the goal of improving ductility of connection and avoiding brittle failure of connection.For flange-plate reinforced connection,beam flange and column flange are not directly connected but by reinforced plate,reinforced plate and beam flange are connected by fillet welding,and reinforced plate and column flange are connected by butt welding.4 1/2 scale flange-plate reinforced moment resisting T shape specimens are fabricated and the shape of flange-plate is rectangular, Q235 steel and E43 welding rod were used.The specimens were designed with our country's code and referenced the USA FEMA350 design method and construction requirements.By changing the dimension of flange-plate,hysteretic behavior of connection is studied. To verify experimental results is correct,ANSYS simulation are proceeded.6 ANSYS models are builded,hysteretic behavior of connection is studied by changing the factor of flange-plate.The results of experiments and ANSYS simultation shows:(1)the plastic hinge is formed 1/3 beam depth from the end of flange-plate under loading which protect the welding of connection,and there are serious buckling in the beam flange and web under ultimate load;(2)for flange-plate reinforced connection,if thickness of flange-plate is smaller than beam flange,the goal of relocation of plastic hinge can't be achieved,so thickness of flange-plate should be bigger than beam flange;(3)the dimension of flange-plate has some effect to behavior of flange-plate reinforced connections;the bigger length and the thicker of flange-plate,the more distance plastic hinge relocated;if length of flange-plate is bigger than 0.8 beam depth, the moment at the centerline of column is large and the difference between shear force at inflection point and stiffener of column is big too,so shear force of panel zone is big and panel may coour brittle failure because of big shear force,special attention shall be paid in the design;when length of flange-plate is small,the reinforced effect of flange-plate to connection is small and the goal of relocation of plastic hinge can't be satisfied;(4)Length of flange-plate is usually definited as 0.5-0.8 beam depth and thickness of flange-plate is usually definited as (1.2-1.4)beam flange thickness.