The Seismic Behavior Analysis Of Steel Frame Structures With Semi-rigid Connections Of The Beam-to-column

Semi-rigid connection is a kind of connections that it’s mechanical properties between rigid connection and hinge connection, the semi-rigid connection can transfer bending moment but there is relative rotation produce between beam and column when loads on the structure. The semi-rigid connections of the beam-to-column would make great effects on the behaviors of steel frames, especially on the dynamic performance, but Chinese current standards always assume beam-to-column connections as fully rigid or pinned hinge to simplify the calculation of the steel frames, rarely involves the contents in rigid connections. Although the assumption has the steel frames’designing and calculation been greatly simplified, the assumption will makes large difference between the theory and practice. For the further understanding of the influence of semi-rigid connection to the steel frame structures’ earthquake resistant capability, several key problems on it are studied:(1) Sap2000was employed to complete the static elastic-plastic pushover analysis for the steel frame with six floors, and a comparative analysis of the results of the static elastic-plastic pushover analysis has been made for the steel frames with different stiffness of beam-to-column connections, and then, the influence of the connection stiffness changes to the seismic performance of the frame structures has been evaluated;(2) A model analysis has been made for the steel frames at different height and different stiffness of beam-to-column connections, the result show that the change of joint stiffness have great influence on the natural vibration period of the high order modes, but to the low order modes the influence can be ignored;(3) Sap2000was employed to complete the elastic time-history analysis under frequently occurred earthquakes and the Elastic-plastic time history analysis under rare earthquakes in8magnitude earthquake area for the steel frames at different height and different stiffness of beam-to-column connections. Compared with the structures’ bottom shear force and vertex displacement at different moments in the earthquake and the structures’ maximum shear force and maximum displacement angle of each floor. The seismic behavior of steel frame with semi-rigid connections has been evaluated, and some reasonable suggestions for seismic design have been proposed.