Mechanical Study Of Steel Frame Flange-plate Reinforced Joints At Beam-end

Flange-plate reinforced joints is a typical flage-reinforced connection. By weldingflange-plate at beam-end, the resistance moment of beam-end cross section has beenimproved, plastic hinge is moved outward from the weld joint of beam and column, toachieving the goal that can improve the ability of node ductility and prevent brittle failure ofthe connection.This paper according to our country’s current specification, then determining the basicdimensions with the beam and colume of the steel fram, Considering the length, thickness,width and shape of the flange-plate, thus designed8full size specimens. According to theactual situation to determine the boundary conditions and loads, and Using the ANSYSsoftware to carries on the finite element simulation for8groups of flange-plate reinforcedjoints specimens, to study the mechanical properties under the effect of cyclic loading. Finally,this paper analyzesd the stress distribution of flange-plate reinforced joints, at the same timeanalyzesd the failure mechanism、failure pattern、ultimate bearing capacity、hystereticperformance、skeleton curves、ductility performance、energy dissipation ability and plasticdeformation ability under low cyclic loading systematically. The results shows：(1) The plastichinge is formed about1/2-1/4beam height from the end of flange-plate under low cyclicloading, which Protecting the beam-column node welds to prevent damage;(2)With thedifferent between plate size and shape of the flange that specimens stress development ofjoints are all the same. Because of the influence of stress concentration, the initial maximumstress of joints appears in the end of the flange plate and the place between beam-columnconnection, then beam-column connection weld stress grows slowly, and end flange platestress to the rapid growth of the first to enter the yield, and ultimately the plastic hingeappeared on beam;(3)The dimension of flange-plate has some effect to behavior offlange-plate reinforced connections,the bigger length and the thicker of flange-plate，the more distance plastic hinge relocated, but the worse hysteretic performance, and also the ability ofductility and energy dissipation performance is more weaker;(4)The rectangular flange-platehas better hysteretic performance, also has better ductility and energy dissipation properties. Itis recommended to use because rectangular flange-plate of reinforced connection is a simplestructure and easy to make;(5) There have a suggestion that applicable for engineering widelypromotion:Length of flange-plate is usually defined as (0.5～0.8times) beam depth andthickness of flange-plate is usually defined as (1.1～1.4times) beam flange thickness, thewidth of flange-plate is usually defined asbeam width plus (4～6times) beam flangethickness.