Behavior Level And Displacement-based Design Method And Research Of High-rise Isolated Structures

Earthquakes are a problem that human beings must face in today's society.When a high-rise building is subjected to an earthquake,its earthquake response is more complex than that of a middle-rise building.At present,the research on the performance design is mainly applied to ordinary middle and low-rise buildings,but there is no complete applicable method for the behavior design of high-rise buildings.In this paper,the seismic performance characteristics of high-rise isolated structures are investigated and studied.It is proposed that the behavior level of the superstructure and the isolated layer should be considered separately,which provides new insights for the behavior description of the behavior design method.Through the planning of the target performance of the performance design,the preciseness of the performance design and the diversity of the functions are put forward,which combine the maintenance of the building functions with the reduction of casualties and economic losses.Through the discussion of the categories of seismic design,the fortification levels of different structures are proposed to effectively ensure the realization of the building's function under earthquakes,so as to realize the design based on the performance.Then,a performance design method of high-rise isolated structure is introduced.The performance design starts from the transformation of multi-degree of freedom into single-degree-of-freedom model,discusses the acceleration response spectrum of displacement response spectrum,and carries out nonlinear dynamic time-history calculation.The additional damping ratio of isolation layer and the upper non linearity are taken into account,and this method is applied to practical engineering to test its feasibility and effectiveness.Then,it is compared with the pushover calculation details of capacity spectrum method,and the advantages and disadvantages of the two methods are compared,as well as the basis for selection.The main conclusions of this paper are as follows:?1?The performance level of high-rise isolated structure is divided and the performance target is quantified.The performance-based design method is studied.Firstly,the fortification level and performance level of high-rise isolated structures are divided and their performance is described in depth.It provides a basis for studying performance-based design methods of high-rise buildings.The performance target of high-rise building structure is quantified by using the index of inter layer displacement angle.?2?For the elastic limit and elastic-plastic limit of the upper structure,the values of damping ratio are summarized.The damping ratio considers the plastic state of the upper structure.When the structure enters the yield state,the damping ratio^?pplays a greater role than the original damping ratio^?hwhen the vibration of the original structure is attenuated.After checking calculation of the high-rise performance design in actual engineering.The shear force of the isolation layer is smaller than that of the upper structure and the yield force is larger.Attention should be paid to the bearing range of the yield force of the rubber bearing.The shear force,displacement and displacement angle between floors under time-history verification are probably in the middle floor,mainly reflected in the sudden increase of its stress.?3?The analysis process of capability spectrum is described.push-over analysis is used to evaluate the performance,which is complementary to the performance design.The concept of push-over analysis method is clear,and it is applied to the evaluation of seismic performance,taking into account the changes caused by factors such as actual site and earthquake distance.For complex high-rise isolated structures and twin high-rise structures,in order to pursue calculation accuracy,the pushover analysis method of capacity spectrum method can be considered to ensure the accuracy of design.For normally used high-rise building structures,the performance design method has sufficient calculation data to ensure the various performance levels of the building.