Seismic Performance Research Of Super High-rise Structure Under Near-fault And Far-filed Long-period Ground Motion

The super high-rise structure is complex and its basic period is long.It is greatly affected by long-period ground motions.The earthquake damage of super high-rise structures in the Mexican Earthquake,the Wenchuan Earthquake and the East Pacific Earthquake in Japan indicates that the super-high-rise structure will be seriously damaged or even collapsed under the motivation of ground motions with rich long periods.The seismic zones are widely distributed within China,and earthquakes occur frequently.With the increasing number of super high-rise structures,the influence of long-period ground motions on these structures has attracted extensive attention from scholars.Studying the seismic performance of super high-rise structures under different types of ground motions to take reasonable aseismatic measures will help reduce the damage caused by earthquakes.In this paper,a super high-rise structure is taken as the research object,and its seismic performance under different types of ground motions is analyzed.The main contents are as follows:(1)To simulate the nonlinear characteristics of concrete comprehensively,the damage constitutive model was used in the structural analysis by writing user material of the ABAQUS.(2)Two types of typical long-period ground motions(far field-like harmonic ground motion and near-fault pulse ground motion)are selected,the near-fault ground motions without velocity pulse and ordinary ground motions are selected to compare with long-period ground motions.The basic characteristics and response spectra of these four types of ground motions are compared and analyzed,The results show that: The peak acceleration,peak velocity and displacement of the near-fault ground motion are larger;The strong motion duration of far-field harmonic-like ground motions is significantly longer than that of the other three types of ground motions.The low-frequency contents of long-period ground motions are abundant,and the long-period ground motions have a greater predominant period than ordinary ground motions;The vibration frequency of the two types of long-period ground motions is close to the vibration frequency of the structure,which tends to cause resonance phenomenon.(3)The structure with the fundamental period more than 6s is selected as the research object,and the finite element model of the super high-rise structure is established by the finite element software ABAQUS.Firstly,the basic characteristics of the model are analyzed.Then two types of long-term ground motions each 7 suits are selected,at the same time,7 suits near-fault ground motions without velocity pulse and 3 ordinary ground motions are selected.In turn,the elastic and elastic-plastic time-history analysis were done under these ground motion records,the results of response such as internal force,displacement and damage degree are compared.The result shows that,the structural responses of different types of ground motions vary greatly,there is a significant change of super high-rise structure under far-field harmonic-like ground motions;With the increase of the floor,the inter-story drift ratio changes drastically.under far-field harmonic-like ground motions;With the enrichment of the long-period components of the ground motion,the position of the maximum inter-story drift ratio of the structure has a tendency to move toward the lower part of the floor;under the two types of long-period ground motion,the top of the super high-rise structure appears to collapse locally.