| High strength steel structure has the advantages of reducing the size of the structural cross-section,reducing steel consumption,saving transportation and installation costs,and so on.Therefore,it is an inevitable trend to apply high strength steel structure to steel structure projects.Facts have proved that the traditional steel frame beam-column connections are prone to brittle failure under the action of earthquake,which is inconsistent with the design concept of "strong connections and weak members".The effective way to improve the seismic performance of steel frame beam-column connections is to produce beam-column connections.Plastic hinges move outward along the beam.At present,weakened and reinforced connections are commonly used in improved connections.Single-rib reinforced beam-column connections are one of the reinforced connections.This paper analyzes the hysteretic performance and fracture performance of the high strength steel single-rib reinforced beam-column connections,and optimizes the single-rib parameters.The specific research content and research results are as follows:（1）The gusset plate test research and finite element analysis:first,the Q690D high strength steel is tested for material properties to provide data for the subsequent finite element model;secondly,4 groups of 12 welded gusset plate specimens are subjected to unidirectional tension and tension compression cycle tests and established a three-dimensional refined nonlinear finite element analysis model,analyzed the failure form,load-displacement curve and bearing capacity of the gusset plate,and compared the test and finite element analysis results to verify the three-dimensional refined nonlinear finite element analysis the validity of the model.（2）Research on the force of the high strength steel single-rib reinforced beam-to-column connections:the three-dimensional refined finite element analysis models of high strength steel ordinary beam-column connection,ordinary steel single-rib reinforced beam-column connection and high strength steel single-rib reinforced beam-column connection were established respectively,and the hysteretic performance and fracture performance of three beam-column connections are studied.The hysteretic performance of the high-strength steel single-rib reinforced connection is better than that of the ordinary steel single-rib reinforced connection.At the same time,the hysteretic performance indicators of the two single-rib reinforced connections are significantly better than the ordinary connection.However,with the increase in yield strength,the ductility and energy dissipation capacity of single-rib reinforced connections of high strength steel have been reduced,indicating that when high strength steel is used in seismic structures,the steel’s yield ratio must be considered to ensure sufficient rotation ability and energy dissipation ability.（3）Optimization analysis of rib parameters based on hysteretic performance and fracture performance:based on the nonlinear finite element analysis model of the above high-strength steel single-rib reinforced beam-column connection,considering the rib length a,rib height b and rib thickness for the three parameters of ts,a variable parameter finite element analysis model is established for each parameter.The hysteresis performance and the fracture performance on the three critical paths are compared and analyzed,and the reasonable range of the above three rib parameters is given:a=（0.63～0.70）hb（hb is the height of the beam section）;b=（0.48～0.57）a;ts=（1.35～1.50）tf（tf is the thickness of the beam flange）. |
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