Study Of Reduction Coefficient Of Coupling Beam Stiffness

With the rapid development of today’s society and the progress oftechnology and science, high-rise buildings have gradually replaced thetraditional architectural forms, and the form of shear wall structures arebecoming mainstream among this buildings, which have brought many difficultproblems to be overcome, the coupling beam is one of the critical problemsamong them. As requirements for the value of stiffness reduction factor ofcoupling beam in existing specifications are not specific, which resulting in arandom choice of the value for a large number of structural designers withoutbasis. However, the couple beam is represented to be one of the most importantcomponents of the shear-wall structure, which should be taken more seriouslyenough. In this dissertation, two different types of Shenzhen actual buildingprojects were studied, which mainly focus on t he influence of the slabs tostiffness of the coupling beam, the influence of the reduction factor of couplebeam stiffness to structure during the elastic state and analysis of the basis of thereasonable choice of coupling beams stiffness in the plastic state. The specificresearch contents are as follows:Firstly, the impacts of the slabs on the stiffness of the coupling beams wereanalyzed. A frame-tube structure which was a actual project case in Shenzhencity was represented to be an engineering background, combining with therequirements about amplification coefficient of beam stiffness in specification,the factors influenced the amplification coefficient of beam stiffness were studied.Analysis results show that the amplification coefficient of the beam stiffness wasinversely proportional to cross-sectional dimension of the beam and proportionalto the beam span. the coupling beam was generally larger in cross-sectionaldimension and smaller in span, the slabs had less impact on the bending stiffnessof coupling beams, which could be neglected the consideration of slabs to thestiffness of coupling beams; while the cross-sectional dimension of couplingbeam was smaller and the span was larger, the influence of slabs on the stiffnessof coupling beams can’t be ignored.Secondly, two structural models under small earthquake were calculated by using SATWE software. The impact of the different coupling beam stiffnessreduction factors on the structural performance indicators and the coupling beams’internal forces were calculated and studied in this section. Analysis results showthat, the reduction of beam stiffness were lead to small changes in the structuralfloor shears and large changes in coupling beam’s internal force. The couplingbeam’s internal force became small while coupling beam stiffness reduced. Thesmaller the reduction factor was, the larger in declining of internal force ofcoupling beams.Finally, pushover analysis of a shear-wall structural model was studied byusing Midas Building software, compared the results of elastic and plastic toelastic under frequent earthquake and rare earthquake. Comparative results showthat, while value of the stiffness reduction factor of coupling beam is choose to0.5, the internal force of this coupling beam in elastic state was equal to theelastic and plastic state under frequent earthquake; however, while value of thestiffness reduction factor of coupling beam is choose to0.2, the internal force ofthis coupling beam in elastic state was equal to the elastic and plastic state underrare earthquake.