Research Of Hysteresis Behavior Of Diagonally Braced Frame Structures With Gusset Plate Connections

Bracing connection system is an essential part of hinged steel frame, whosehysteretic behavior capability affects the integral responses of the frame underlow-cycle fatigue loading. The gusset plate connections have a smaller stiffeness,and are often supposed to ideal hinges in engineering design. The gusset plates willinduce secondary internal force to beams and columns when the steel framesubjected to severe cyclic loadings, which will have negative effects on thestructural safety. So the secondary internal force is can not be neglected.In this paper, by using the way which connected tests with Abaqus program, aparametric study was conducted to study hysteretic behavior、low-cycle fatigue lifeand failure mode of the brace system under low-cycle fatigue loading so that theprinciple of design is guaranteed. The influence of the gusset plates on the forcebetween the gusset plates and the beams and columns was also explored. The maincontests are listed as follows:Firstly, summary of study and application status of bracing system was made;baced on the principle of design and several important parameters, such aswidth-thickness ratios of brace, connection mode of brace and gusset plate，tendiagonally braced single-story single-span frame structures specimens were designed,and make sure the feasibility of test by analysis of Abaqus.Secondly, hypocritical statics tests on frame system under cyclic loading wereconducted to measure hysteresis curves of load and displacement of frame system.Meanwhile, the strain on the key points of gusset plate、frame and brace wasmeasured， so was out-of-plane deformation of brace. In the progress of experiment,the phenomenon and failure mode were also observed.Thirdly, some performance indexes of the five test specimens were studied indetail, such as hysteresis curves、skeleton curve、ductility、the capacity of energydissipation、the degeneration of stiffness、low-cycle fatigue life and the secondarymoments in beams and columns. The test results of different tests were comparedand analyzed. Reasonable explains were given based on the variation of specimenparameters.Finally, shell elements were used in ABAQUS. The finite element models ofthe braced frame with hinged joints were built up, in which the test results of fivespecimens were imitated. The performance indexes of all ten specimen which weredesigned above were analyzed deeply, the influence regularity of key parameters was discussed, the behavior of braced frame with hinged joints and gusset plateconnections was revealed.