Research On Strengthen Coloumn End Moment For Frame Structure Under Bi-horizontal Earthquakes Based On The Beam Sidesway Mechanism

Chinese seismic code use “moment augment factor of column”to make cloumns’flexural bearing capacity are stronger than beams’ in frame structure seismicdesign.This method can guide frame’s energy dissipation rely on yielding of beams’ end.Beams’ ends not only have excellent capacity to dissipate energy, but also can guideinternal force redistribution.The formation of reasonable beams mixed hingemechanism for the whole structure seismic and collapse resistance has a vital role.Although the code for seismic design of buildings (GB50011-2010)(hereinafter referredto as the seismic code) has increased the moment augment factor of column csignificantly, but still can’t avoid the plastic hinge at the end of the column. So theresearch of moment augment factor of column is very necessary.In order to find the effective moment augment factor of column to guide structuregenerate ideal “beam hinge mechanism”, in this paper, a series of typical plane frameslocated in2kind of areas(7degree0.15g,8degree0.3g) are designed following sesmicdesign code(2010edition). Nonlinear structure model is established in opensees finiteelement analysis software.Through this software, coloumns’ reinforcement strength isincreased and can’t reach yield point under large earthquake, other materials are same asnoemal ones. To reduce impact caused by the randomness of the ground motion, Thisarticle selects30ground motion which conform to the requirements,and then extracts ofinternal force with the schedule undet large earthquake. According to the internal forcewith the schedule, we can get reasonable reinfoecement area of cloumn which based onsection does not yield. The self-made matlab biaxial eccentric compression program isused for calculation.According to the current seismic code formula6.2.2-1,6.2.2-2, we can get momentaugment factor of column c calwhich based on section does not yield if reasonablereinfoecement area of column has got.Regulation and information of moment augmentfactor of column will be analyzed and summarized, and then according to the statisticalresults suggested values will be given.Finally, new structure according to the proposedmoment augment factor is designed,it’s rationality will be reviewed.Through the work above, this paper get the following conclusion:(1) This paper’s design method which based on section does not yield can reducethe number of hinge at the end of column and guide guide frame’s energy dissipation rely on yielding of beams’ end.(2) According to current seismic code formula6.2.2-1，moment augment factor ofcolumn for framework of7degree0.15g and8degree0.3g does not changeobviously from layer to layer except bottom layer and top layer. From layer tolayer, columns’ moment augment factor corner column、side column changemore obviously than middle column， low intensity area changes moreobviously than high intensity area.(3) According to the method in this paper, moment augment factor of column forframework of7degree0.15g and8degree0.3g has increased much more than1.3、1.5.But for framework of7degree0.15g seismic measures such asminimum reinforcement ratio often cover up this insufficient.