Research On Pseudo Dynamic Testing Of The Knee Bracd Steel Frames

The knee braced steel frame(KBF),regarded as a new fashioned dissipation energy braced structure form,its dominant characteristic is one end of the knee brace joint the pillar,the other end connects with girder,both conjunctures should be just met.One end of the supporting strut link with the knee brace,the other end connects with the girder node, providing lateral stiffness for the frame,the knee brace designed as dissipation energy component in bracing system,when encounter with infrequent earthquakes,the knee brace dissipates energy by model deformation,and then submits before the major components so as to protect the main body structure.KBF synthesizes the merits of big stiffness on concentrically braced steel frame(CBF) and Moment-resisting frame(MRF) good ductility,conquering the disadvantage of eccentrically braced steel frame(EBF) to sacrifice main body structure submitted to dissipation energy.Its stiffness is strong enough and with very good ductility,superior dissipation-energy performance,the model demolishment controlling in secondary component of the structure making it is quite easy to restore,which is suitable for high intensity earthquake area and effective to antiside structural braced forms.A series of overseas research has already launched to this new bracing system,but not yet forming into systemic theory.In Our country,KBF research just to be started with. Because China is a country that earthquake is more likely to occur and most regions locate in the area at six and higher degree,for the sake of fully using superiority of KBF, exploring its applicability,conducting the experimental study is of great importance both in theory and practical value on earthquake resistance performance.In order to study earthquake resistance performance of the knee braced frames,this article experiments with two-layer knee brace steel frame model in the proportion of reduced scaling 1/3,adopting the MTS battery solution servo loading system and control software carries on experimental study of simulate earthquake respond to this model, namely Pseudo dynamic testing research,analyzing the characteristic of structure pressed by horizontal earthquake,model deformation characteristic,obtaining acceleration, horizontal displacement,the fundus shearing force time-hisotry curve,which also studies earthquake dissipation-energy performance from many aspects,such as structure stiffness, intensity and deformation,stagnation curve,etc,with finite element analysis software SAP2000 to carry on the knee braced steel frame elastoplasticity time history analysis,and then compare with the pseudo dynamic testing result.