Analysis And Research On Long-period Ground Motion Characteristics And Seismic Response Of Super High-rise Structure

In order to study the engineering characteristics of long-period ground motions,ordinary ground motions and vertical ground motions,explore the actual attenuation law of the straight line in the standard design spectrum,and compare and analyze the long-period building structures to long-period ground motions and ordinary earthquakes The difference in seismic response between dynamic and vertical ground motions.This paper selects some stations in the Chi-Chi earthquake in Taiwan,China,and establishes a finite element model of the long-period building structure for the following research.(1)By analyzing the time history of the ground motion,make a preliminary understanding of the long-period ground motion and ordinary ground motion;separately calculate the acceleration peak,velocity peak,displacement peak value of the long-period ground motion and ordinary ground motion under different sites with the epicentral distance Decay law;statistical damping ratio is 0.02,0.05,0.1,respectively,the excellent period value of acceleration,velocity,displacement response spectrum.It is found that the near-field long-period ground motion pulse phenomenon is obvious,and the far-field long-period ground motion tail wave appears pulse family;the ground motion peak value decays faster with the epicentral distance;the excellent period of the speed response spectrum of the long-cycle ground motion is greater than that of ordinary ground motion.(2)Statistics on the attenuation law of vertical acceleration,velocity peak,and displacement peak with the epicentral distance;it is found that the above peaks are decreasing as the epicentral distance increases.Calculating the ratio of vertical and horizontal acceleration peaks,it is found that most of the values are greater than 0.65;in the near-fault area,the ratio of some stations even reaches 1.0.The average acceleration response spectrum of vertical ground motion is compared with its corresponding horizontal average acceleration response spectrum.It is obtained that when the epicentral distance is small,the spectral ratio is greater than 0.65 in a short period,and the remaining sections are less than 0.65;when the epicentral distance is large At this time,the spectral ratio is greater than 0.65 in a longer period,and the remaining sections are less than 0.65.(3)The two-stage exponential decay model and the least squares segmentation method are used to calculate the design β spectrum(ζ = 0.05)of horizontal long-period and vertical ground motions,and the relevant parameters at different sites and different epicentral distances are obtained Value,and conduct a comparative study with the current specification spectrum;the statistically designed horizontal design β spectrum is much larger than the specification β spectrum;the statistically designed vertical design β spectrum is also much larger than the design spectrum given by the specification.(4)Establish a finite element model of the high-rise building structure,and use the response spectrum method to calculate the standard design spectrum and the design spectrum statistically calculated in this paper;enter the ordinary ground motion,longperiod ground motion,and vertical ground motion respectively Based on the analysis of the process,the seismic response of the long-period building structure to the design spectrum based on the long-period seismic motion and the long-period seismic motion is significantly greater than that of the normative spectrum and ordinary ground motion.Compared with the far-field vertical ground motion,the near field Vertical ground motions can cause the building structure to generate large axial forces and interlayer shear forces.