Seismic Response Analysis Of RC Shear Wall High-rise Base-Isolated Structure On Deep Deposite

Seismic isolation technology,renowned as the pinnacle of contemporary and wellestablished building vibration control methodologies,finds widespread application in real-world engineering endeavors across the globe,spanning both domestic and international domains.Extensive experimentation and empirical evidence unequivocally demonstrate the effectiveness of seismic isolation technology in attenuating horizontal seismic response within superstructures.With prudent design considerations,this technology guarantees the structural integrity,non-structural elements,and internal facilities of buildings,substantially preserving their post-earthquake operational functionality after seismic events.The promulgation of the "Regulations on Seismic Protection of Construction Engineering" in 2021,coupled with the implementation of the"Standard for Seismic Isolation Design of Buildings,"has engendered heightened requisites concerning the design and construction quality of newly constructed seismicisolated buildings.These regulations have significantly expanded the scope of seismic isolation technology.In recent times,the domestic construction industry has witnessed the emergence of high-rise structures utilizing seismic isolation technology with shear walls on Class III sites.Nonetheless,there remains an inadequate discourse surrounding the efficacy and safety aspects of implementing seismic isolation in high-rise buildings erected on deep and soft soil sites.This paper focuses on a case study of a high-rise seismic-isolated building,situated in a residential complex within a high-intensity seismic zone,atop soft soil.Nonlinear seismic analysis models are developed,taking into account the flexuralshear coupling behavior of the high-rise superstructure,the overturning rotation of the isolation layer,and the effect of soil-structure interaction.Nonlinear seismic response analysis is conducted to investigate the seismic performance of the structure.The key contributions of this paper are summarized as follows:1.Based on the design data of the base-isolated building,a comprehensive twodimensional nonlinear seismic analysis model is formulated to investigate the dynamic interaction between the isolation layer and the superstructure,concerning the direction with a significant aspect ratio.In this model,the superstructure is represented by a discrete flexural-shear coupling model,accounting for the collective influence of overall bending and shear deformations within the shear wall structure.Simultaneously,the isolation layer is characterized by an analytical model capable of capturing its rotational response and non-uniform vertical displacements at various isolation bearings along distinct axes.2.Drawing from the seismic safety evaluation report of the building’s site,the pertinent parameters for the site’s soil layers are obtained.Leveraging this crucial data,a meticulously crafted one-dimensional nonlinear analysis model for assessing the soil response is formulated.3.With the bedrock design spectrum provided in the seismic safety assessment report as the target,a selection of bedrock earthquake ground motion time histories is obtained for both design-based level and maximum-considered level earthquakes,employing waveform selection,amplitude scaling,and spectrum matching method.Subsequently,employing one-dimensional nonlinear site soil response analysis,the freefield ground motion at the surface of soil corresponding to the aforementioned bedrock earthquake recorders is determined.4.Based on the two models and the two sets of seismic input,three analysis scenarios are established:(A)one-step analysis considering soil-structure interaction,(B)step-bystep analysis of without considering soil-structure interaction.,and(C)analysis without considering site soil condition.Each scenario includes both base-isolated and base-fixed model cases.5.Based on the computations from Scenario A,the seismic response of the high-rise seismic-isolated building situated on deep deposit is evaluated.It is noted that while the isolation layer effectively reduces the maximum inter-story drift response of the superstructure,the rubber bearings may experience significant tensile stresses due to the overall rotation of the isolation layer,and there may even be a risk of tensile-shear failure.6.By comparing the seismic responses of the structure under the three different scenarios,the influence of soil-structure interaction and site effects on the seismic performance of the base-isolated building is examined.It is indicated that,for the site soil layers and the building considered in this study,the site effects have a greater impact than the effect of soil-structure interaction.Moreover,Site effects tend to increase the seismic response of the high-rise base-isolated building,thereby affecting the isolation efficiency of the isolation layer.On the other hand,soil-structure interaction tends to reduce the seismic response of the high-rise base-isolated building.