Research On Reasonable Arrangement Of SHS-joint Braces In Steel Frame

In recent years, the Square Hollow Section (SHS) is being applied in frame columnsand truss structures more and more widely to replace the traditional I-section andH-section mainly due to its excellent structural and economical performance. How toconnect the bars of steel structures seems to be particularly important. The directlywelded SHS joint has a wide range of prospects in development and application becauseit has unique superiority of direct force transmission，simple form, easy processing andsaving much steel. The SHS joint with reasonable parameters has excellent seismicperformance, on the basis of which my College has been developing SHS-joint seismicsupport system. When experiencing the combined effect of lateral load and vertical load,the lateral resistance of the pure steel frame can be achieved by increasing the bendingstiffness of beams and columns. However, such practice is not economical, especially forhigh-rise frames. Therefore it is necessary to provide in frames some support systemwhose seismic performance is adequate to form brace-steel frame structure with duallateral resistance. Braced steel frame has been widely used in steel structure due to itsrelatively good seismic performance and efficient structural system. But how to arrangebraces economically and reasonably to effectively improve the seismic capacity hasbecome a critical issue in the design of steel frame structures. This research aims atstudying the reasonable arrangement of braces by elastic and plastic time history analysison steel frames which contain SHS-joint braces.A general-purpose finite element ANSYS software is used in this paper to:1)Set upframe models to analyze and contrast with previous findings and determine whether thisanalysis is feasible or not.2）Set up the dynamic time history analysis models of variousSHS-joint braced frames, which mainly include monoclinic lever and K-shapedeccentrically braced frames.3) Analyze the dynamic performance of SHS-joint bracedsteel frames under seismic waves, and compare with that of pure steel frames to know theeffect of braces on the performance of steel frames.4) Analyze the dynamic performanceof SHS-joint braced frames when exposed to a variety of seismic waves, and draw thetime history curves of each vertex displacement, the total bottom shear response, themaximum storey drift and vertex acceleration response,and the envelopes of storey driftand displacement under different situations.5) Analyze the performance of eccentrically braced steel frames in different arrangement of braces and to find a more reasonablearrangement of SHS-joint braces in steel frames.