Seismic Performance Research Of Out-of-code High-rise Building Structure Under Near-fault And Far-filed Ground Motion

High-rise building structure has complicated seismic response and complex failure mechanism under strong earthquakes, when there is damage occurred and caused great losses in the past earthquake. Near-fault ground motion is usually accompanied by long period velocity pulse and far-field ground motion response of long-period structure is very significant. Therefore, the seismic performance of high-rise building structure under near-fault and far-filed ground motion will undergo a severe test. It is of great significance to study the seismic response and damping seismic measures of high-rise building structure.In order to more accurately assess the seismic performance of high-rise structure under ground motions and reduce the damage caused by earthquake, the main research contents of this paper are as follows:(1)The development and structural system of tall buildings are presented; Overview of the finite element analysis theory and dynamic nonlinear time history analysis method; Summarized the causes of the long period structure damage and domestic and foreign research results on the seismic resistance of tall building structures.(2)The definition, basic characteristics and influence on engineering of near-fault ground motion and long period far-field ground motin are presented. Selected 7 suits of near-fault ground motion without velocity pulses, 7 suits of near-fault ground motion pulse with velocity pulses and 7 suits of far-field ground motion respectively and discussed the characteristics of frequency spectrum about these spectra. The results show that the average ground motion amplification coefficient spectrum distribution of far-field ground motion is the most extensive, so the long-period seismic response of structure effects is more obvious. The growth amplitude of relative displacement response spectrum of near-fault ground motion is especially obvious, may have a great influence on the long period structure.(3)A high-rise building beyond the code-specification, Lanzhou Center-Grade A office building, was taken as the background. With the help of finite element program ETABS2013, a more fine overall structure finite element model is established. These suites of ground motion records were taken as inputs to carry out time history analysis under the frequent and rare earthquake. The results show that seismic responses of structure under far-field ground motion is more obvious, especially the story drift under far-field ground motion has been far more than the limitation as described in the specification. This indicated it is more safety for the long-period structures to do seismic performance analysis by selecting the far-field ground motion.(4)In order to reduce the response of the structure under the ground motion,the plan of dampers uniformed layout in the outer frame and the plan of dampers uniformed layout between the outer frame and the core tube were used to optimized the structure respectively, and the time analysis were used again. The results show that the plan of dampers uniformed layout between the outer frame and the core tube has an optimation performance on energy dissipation and seismic mitigation, and this method can effectively reduce the seismic response of the structure.Results above provide a reference for seismic theory of the out-of-code high-rise building structure. At the same time, to provide some value for the design and check of the high-rise building structure in the future.