| The high strength steel structure is one of the importatnt trend in development of steel structures.Reliable beam-to-column joints are the basis of ultilizing the advantages of the material propertis of high strength steel and a guarantee of the seismic performance of the high strength steel structures.This dissertation selected the high strength steel platereinforced beam-to-column joints that are expected to have good prospects as the research object,and conduct investigations on the seismic performance of this joint form by experimental study,numerical simulation and theoretical analysis,in order to propose the recommended joint configurations and the seismic design methods of high strength steel plate-reinforced beam-to-column joints.The main research works in the dissertation are as follows.(1)Considering differnet combinations of Q345 or Q460 beams and Q345,Q460 or Q890 columns,changing the constructional parameters of joints,e.g.the reinforced ratio and the panel zone strength ratio,8 cover-plate reinforced beam-to-column joint and 8 flange-plate reinforced beam-to-column joint full-scale specimens were designed and cyclic loaded.The failure mode,the resistance,the stiffness,the energy dissipation and the mechanicl properties of the panel zone of each specimen were analyzed,and the ductility of each specimen was evaluated based on the maximum story drift rotation,the plastic story drift rotation and the ductility ratio.(2)Finte element models that can accurately consider the main constructional parameters of high strength steel plate-reinforced beam-to-column joints were built and validated with the experimental results.Parametric analysis was conducted with the finte element models,and a total of 52 cover-plate reinforced beam-to-column joint models and 56 flange-plate reinforced beam-to-column joint models were calculated.The mechanical indexes of joints with different material combinations or constructional parameters were obtained.The phenomena of shear reversing in the shear plates was proposed,and the reinforcing plates were recommended to be checked for the strength under bending moments and shear forces in design.(3)Based on the experimental results and the finite element analysis results,the applicability of the exsiting design methods for beam-to-column joints were discussed for the high strength steel plate-reinforced beam-to-column jonits,and the recommended configurations,the stiffness calculation methods,the resistance checking methods and the seismic design methods of high strength steel plate-reinforced beam-to-column joints were proposed.The proposed design method could offer references for the applications of high strength steel plate-reinforced beam-to-column joints in seismic design.(4)A model of the moment-panel zone shear rotation curves in flange-welded beamto-column joints,as well as an analysis model of steel frames with the panel zone deformation in consideration,was proposed.The calculation programs that considered the panel zone deformation with the parallelogram model,the scissors model and the column-side spring model were built.Working examples were analyzed with the calculation results of different models compared.The necessity to consider the deformation of the panel zone in design of high strength steel frames was analyzed,with a practical method to consider the panel zone deformation in analysis of steel frames proposed. |
