Research On Aseismic Design And Vulnerability Analysis Of The Super High-rise Structure Under Long-period Ground Motions

The long-period ground motion may cause more serious damage to structures than the ordinary ground motion,especially to long-period structures.The site predominant period of the long-period ground motion is similar to the natural period of long-period structures,which is easy to form double resonance,resulting in more intense structural response.Therefore,it is necessary to conduct in-depth research on aseismic design and seismic performance evaluation of super high-rise structures under the long-period ground motion.Based on the practical engineering of a frame-core tube structure with a height of 200.5 meters,this paper studies the aseismic design of the structure under different types of long-period ground motions,and analyzes the seismic performance of the damper-added structure from the perspectives of the structural elements and the whole structure.The main research contents and conclusions are as follows:(1)Select 7 far-field long-period ground motions,7 near-field pulse-type long-period ground motions,and 7 near-field non-pulse-type long-period ground motions.Compare the spectral characteristics of the three types of long-period ground motions.(2)Three damping schemes are designed based on the principles of stiffness,displacement,and shear force,and Perform-3D is used to complete the dynamic time-history analysis under three types of long-period ground motions.The damping effects of different schemes are compared through aseismic macro-indexes including interlayer displacement angle,base shear force,overthrow bending moment and energy-dissipation of elements.The results show that the viscous dampers in the three damping structures can play the role of energy dissipation,and the damping effect under the rare earthquake is slightly less than that under the frequent earthquake.For frame-core tube structures similar to this engineering,arranging viscous dampers on the floors with larger interlayer displacement angles can maximize the damping effect,reduce the cross-section of the elements,and reduce the cost.Arranging the viscous dampers on the floors with stiffness mutation may also achieve a superior effect.(3)Taking the damping structure as the research object,the performance level division and section check of the main structural elements are carried out,and the damage of the elements under different types of long-period ground motions is further discussed.The results show that the damping structure can meet the performance level requirements of the standard,and the damage degree of the main elements under the three different types of ground motions is in descending order: far-field> near-field pulse type> near-field non-pulse type.(4)Determine the probability of the damping structure entering different failure states through the seismic vulnerability analysis based on IDA,so as to evaluate the seismic performance and collapse resistance of the structure.The results show that the overall descending order of the exceeding probability of structural demand is as follows: far-field>near-field pulse type> near-field non-pulse type.However,when the PGA is less than 0.4g,the exceeding probability of the structure under severe damage level may be near-field pulse type>far-field.Therefore,when evaluating the seismic performance of the structure under longperiod ground motions,it cannot be simply considered that the impact of far-field ground motions is always higher than that of near-field pulse-type ground motions.(5)Comparing the IM average value and CMR value of the structure beyond the specified limit state under three different types of ground motions,it can be generally considered that the far-field long-period ground motion may cause the most damage to the structure,and the near-field pulse-type ground motion takes the second place,in the near field is the second,the damage under the near-field non-pulse-type ground motion is the minimum.