Nonlinear Dynamic Analysis Of RC Frame Shear Structure Under Near Fault Earthquake

Earthquakes are considered to be one of the most important causes of structural damage and even destroy.The near fault area of the earthquake is the most serious area of earthquake damage.The common practice at this stage is not to build large civil structures in the near fault zone.But for a variety of reasons,engineering structures are often built in near fault areas.Therefore,the earthquake resistance of the near fault area is very important.The frame shear structure is one of the commonly used structural forms at the high level of the present stage.It combines the shear wall structure with the frame structure.It has the advantages of the frame structure and the shear wall structure respectively.It is necessary to study the response of this kind of structure under the action of near fault earthquake.The main contents of this paper are as follows:(1)This paper uses a large finite element program SAP2000 to establish a reinforced concrete frame shear structure conforming to the current norms of China.And the parameters of the structure are reasonably selected.In order to consider the plasticity of the reinforced concrete frame shear wall structure,the plastic hinge is added to the model.The material is simulated with a nonlinear material constitutive model.In order to ensure the correctness of the structure model,the model analysis and the response spectrum analysis are carried out.By analyzing the displacement of vibration mode and response spectrum,it is found that the modal mode and mode frequency meet the requirements of the code,and the maximum displacement of the response spectrum is also within the specification limit.(2)To compare the effects of near fault ground motion and non near fault ground motion on the seismic response of the frame shear wall structure.The time history analysis of frame shear structure is carried out using non near fault ground motion and near fault ground motion under the condition of frequent earthquake intensity and rare ground motion intensity.Through the analysis of the two results,it is found that the near fault ground motion and the maximum interlayer angle of frame shear structure under the action of non near fault can meet the specification requirements.There is no significant difference in seismic response between non near fault ground motion and near fault ground motion under the conditions of earthquake intensity.Under the condition of rare earthquake intensity,the difference between the two is obvious.The interlayer angle of the near fault ground motion is obvious,which is close to the standard limit value.(3)To further determine the influence of the velocity pulse on the frame shear structure in the near fault ground motion.In the near fault earthquake,the velocity pulse is filtered and the structure of the near fault ground motion remainder is input.By comparing the difference between the near fault ground motion and the structural response of the near fault ground motion,we find that the maximum displacement and the maximum interlayer angle of the near fault ground motion are smaller after the velocity pulse is removed.The displacement directivity effect caused by the velocity pulse is disappearing.It can be further explained that the important cause of the great destructiveness of the near fault ground motion is the near fault velocity pulse.(4)Comparison of frame shear wall structure in near fault ground motions and non near fault ground motion under earthquake response: near fault ground motion due to the existence of velocity pulse will cause obvious displacement pulse in the structural response direction,nearly fault ground motion adjustment for the rare earthquake strong after a peak shift pulse becomes larger,the number of increased.Therefore,in order to reduce the displacement response due to the near fault action,this paper puts forward that in the frame shear wall structure,the shear wall should be arranged according to the "uniform,symmetrical and dispersed" layout principle,and the effect of near fault action should be considered properly.Based on the analysis of the seismic response of frame shear wall structure under the action of near fault ground motion,non near fault ground motion and near fault ground motion allowance,this paper illustrates that the near fault ground motion is much more destructive than the ordinary earthquake.The velocity pulse direction of near fault ground motion is obtained through the analysis of velocity pulse.The displacement response of frame shear wall structure will have a number of obvious displacement pulses,and the intensity of displacement pulse will increase with the increase of ground motion intensity.Based on the above analysis,we strive to build a frame shear wall structure in near fault area in future,based on the destructive characteristics of near fault velocity pulse,and rationally arrange the shear wall to resist the influence of velocity pulse.