Study On Seismic Performance Of Shear Wall Structures With Tensile Stress In Wall Limbs Under Moderate Earthquakes In High Intensity Areas

In accordance with the requirements of China’s current standard,performance-based design methods are used for super high-rise buildings.Performance-based design has clear requirements for the structure’s performance under moderate earthquakes,which need to be achieved through calculation and construction measures.For super high-rise shear wall structures in high-intensity areas,during the analysis of the non-yield calculation of moderate earthquakes,because of the large structure height and strong earthquake action,the problem that the nominal tensile stress of the wall limb exceeds the standard value of concrete tensile strength will occur at the bottom of the structure.In the concrete design,the nominal tensile stress of the bottom limbs of some structures can be as high as 5～6 times the standard value of the concrete tensile strength.The seismic bearing capacity of shear wall limbs will be reduced under the action of tensile stress.China’s relevant standars have clear design requirements,but the mechanism and specific measures in the design deserve further study.Based on this,this article studies the nominal tensile stress of wall limbs in high intensity areas,mainly including the following:(1)Conduct literature research on the nominal tensile stress of the wall limbs of the shear wall structure.(2)The influencing factors of non-yielding analysis of moderate earthquake of superhigh-rise shear wall structures in high-intensity areas are discussed.The effects of damping ratio and coupling beam stiffness reduction coefficient on nominal tensile stress are mainly analyzed.(3)The method of solving the tensile stress of the wall limbs in the structural design is to arrange the section steel in the wall limbs according to the equivalent method of elastic modulus.This article has derived a more convenient and practical calculation formula for the area required to arrange the section steel according to the requirements of the standard.This kind of section steel layout method is described by taking the design of a super highrise shear wall structure in a high intensity area as an example.(4)Take a super-high-rise shear wall structure in a high-intensity area as an example,conduct the dynamic elastic-plastic analysis of the middle-earthquake,compare the dynamic calculation results with the non-yield analysis results of the middle-earthquake,and analyze the influence of the dynamic effect on the tensile stress calculation and seismic performance of the middle-earthquake wall.(5)Through example calculation,the dynamic elastic-plastic response and static elasticplastic response of a shear wall structure with excessive tensile stress in moderate earthquake are analyzed under a large earthquake,and examine the large earthquake performance of the structure after the steel is configured according to the nominal tensile stress of the moderate earthquake wall limb.Based on the above research,this article draws the following conclusions:(1)As the structural damping ratio increases,the number of wall limbs whose nominal tensile stress exceeds the limit decreases as a whole,and the wall limb tensile stress decreases.As the stiffness reduction factor of the coupling beam increases,the number of wall limbs whose nominal tensile stress exceeds the limit increases overall,and the wall limb tensile stress increases.(2)The calculation formula of the section steel area and configuration method of the section steel proposed in this paper can more easily make the structure design meet the control of tensile stress in the code.(3)The overall index of non-yield calculation of moderate earthquakes such as interfloor displacement angle and inter-floor shear force are greater than the results of elasticplastic calculation of moderate earthquake;the tensile force of wall limb calculated by nonyield of moderate earthquake is larger than that of elastic-plastic calculation of moderate earthquake.After the section steel is configured,the inter-floor displacement angle is reduced,the base shear force is increased,the seismic performance of the shear wall is improved,the tensile stress of the wall limbs is reduced,and the shear capacity of the tensioned wall limbs is increased.(4)The elastic-plastic analysis and static elastic-plastic analysis of large earthquake show that the configuration of steel sections for wall limbs whose nominal tensile stress exceeds the limit for moderate earthquakes improves the overall seismic performance and the seismic performance of tensioned wall limbs.