چكيده به لاتين
In design codes,the ability of a strucural system to perform in the nonelinear zone,expressed by introducing the factor of ductility.In fact,this factor is for avoiding nonelinear analysis.Response modification factor of building involves features like:ductility,undeterminity and overstrength which exists in the structure of a building.Because of the simplicity of linear analysis, most codes such as NEHRP UBC and Iran seismic code,evaluate the seismic force which applies to buildings with linear elastic analysis;yet in order to use the whole capacity of building during intense earthquakes,it is necessary for the structure to enter to the nonelinear zone.Hence,the seismic force which is derived from linear analysis has reduced by means of response modification factor (R) and so the building will be designated for smaller force.In other words response modification factor causes to reduce linear response spectrum to nonelinear response spectrum.
In this dissertation,for evaluating the response modification factor (R) of IMF steel frames,we have applied nonelinear static analysis(push over) by SAP2000v19 software.To determine the correctness of works done, we used nonelinear incremental dynamic analysis to survey the effect of aperture,we used 2D and 3D models and designed them according to tenth issue of design code of Iran.To see the effect of height on the response modification factor ,we used buildings with 2,4,8,12 stories.the results show that the effect of considering aperture in modeling of the buildings for design,lead to bigger amounts and with increse in number of stories,we get lesser Rs.while there is one R in the code for buildings with different heights.this issue shows more consideration in choosing appropriate R in design of tall buildings.
Keywords: response modification factor,nonelinear analysis,IMF,diaphragm effect
