Study And Application On Internal Force Redistribution Of RC Frame-Shear Wall Structure Under Earthquake Loading

Frame–shear wall structure is composed of two different kinds of structure forms,the diversity of stress mechanism and deformation characteristics of them is larger.Asthe stiffnessdegradation law is different between frame structure and shear wallstructure,thestiffness ratio of them varied everytimein the inelastic phase, therefore thecondition of internal force distribution is relatively complicated.Accordingly modelsareestablishedbased on the different stiffness characteristic values,then dynamictime-history analyses is carried out on the models,at first by means of the developmentlawof top displacement,base shearand interlayer displacement Angle,the effect ofchanges in stiffness characteristic valuesis found on seismic indicators;Then thestudyinvestigates the detailed developing process ofthe bottom frame undertaking theshear force under different earthquake loadings;Finally this paper makes a research onthe influence of the stiffness characteristic value on the frame-wall structure stresscharacteristic in inelastic phase,then according to the analysis discuss the applicationproblems.Through theabove analysis draw the following preliminary conclusions:①As the stiffness characteristic value increases, under the same earthquakeloading, the peak of the interlayer displacement Angle and the top floor displacementalso rises, meanwhileas the earthquake actionenhances the gains increases.On the otherhand, with the stiffness characteristic value increases, the response of the base sheargradually decreases, at the same time as the earthquake actionenhances the gainsdecreases.②At first shear wall strengthened area at the bottom structure yield,under the smallearthquake,middle earthquake loading, the structuresare still in elastic stage and withthe stiffness characteristic value increases the shear force ratioalso increases.Meanwhileunder the large earthquake, ultra earthquake loading, the structures have entered theelastic-plastic stage and with the stiffness characteristicvalue increases the shear forceratioincreases too. To sum up, with the stiffness characteristic value increases the shearforce ratio of the bottom frame also increases, this conclusion applies to both elasticstage and elastic-plastic stage.③Under the small earthquake,middle earthquake loading,the shear distributionalong the floor of frame is quite regular, that is from down to up first increases then decreases; Under the large earthquake, ultra earthquake loading, the the sheardistribution along the floor of frame is relatively complicated, that is from down to uptend to average. Therefore, it is reasonable that code does not distinguish floors to adjustthe frame shear force.④It is relatively reasonable to evaluate structure stiffness degradationaccording tothe interlayer displacement Angle, with the interlayer displacement Angle increases theshear force rises, seismic force between the wall limbs and frame appears obviousredistribution, the frame plays the nice role of the "second line of defence". It’s better toconsider the effects on the capacity of the frame when the plastic development causes are-distribution of the internal force during the design of the frame-shearwalls.Meanwhile it is better to consider the effects of stiffnessdegradation of shear wallduring the adjust.When interlayer displacement Angle of structure around1/550, theshear ratioof frame is the largest, preliminary think it is the most unfavorable stress stateof frame at the moment.