A Study on Maximum Responses and Their Variances of Elasto-Plastic Structures Subjected to Synthesized Ground Motions

Author(s):  
Akira Sone ◽  
Ichiro Ichihashi ◽  
Arata Masuda

A number of artificial earthquake ground motions compatible with time-frequency characteristics of recorded actual earthquake ground motions as well as the given target response spectrum are generated using wavelet transform. The coefficient of variation (C.O.V..) of maximum displacement on elasto-plastic SDOF systems excited by these artificial ground motions are numerically evaluated.

Author(s):  
Ichiro Ichihashi ◽  
Akira Sone ◽  
Arata Masuda ◽  
Daisuke Iba

In this paper, a number of artificial earthquake ground motions compatible with time-frequency characteristics of recorded actual earthquake ground motion as well as the given target response spectrum are generated using wavelet transform. The maximum non-dimensional displacement of elasto-plastic structures excited these artificial earthquake ground motions are calculated numerically. Displacement response, velocity response and cumulative input energy are shown in the case of the ground motion which cause larger displacement response. Under the given design response spectrum, a selection manner of generated artificial earthquake ground motion which causes lager maximum displacement response of elasto-plastic structure are suggested.


Author(s):  
Arata Masuda ◽  
Akira Sone

In this paper, a new method for generating artificial earthquake motions is proposed, in which one can explicitly design the time-frequency characteristics of the earthquake as well as its response spectra. First, it is shown that the velocity response spectrum at a specific period can be interpreted as the maximum amplitude of the wavelet transform in which the velocity impulse response function of a single-degree-of-freedom system is used as the analyzing wavelet. Using this relationship, a spectrum-compatible artificial earthquake motion with the desirable time-frequency characteristics is generated in the wavelet domain by an iterative correction-projection scheme. Some illustrative examples are investigated to demonstrate the capability and the practicability of the proposed scheme.


1989 ◽  
Vol 5 (3) ◽  
pp. 477-493 ◽  
Author(s):  
Michael E. Barenberg

The validity of evaluating the inelastic response of a structure subjected to an artificial accelerogram in lieu of a suite of eight recorded ground motions is determined by analyzing the inelastic response of single-degree-of-freedom oscillators over a range of frequencies from 1.0 to 10.0 Hz. A normalization procedure to minimize the dispersion in the ductility response of the oscillators subjected to the recorded ground motions is investigated. The artificial accelerogram is derived by superimposing closely spaced sine waves in order to match a target response spectrum. The results show that the artificial accelerogram is expected to produce the same amount of damage as the average of the recorded strong ground motions for structures with an initial frequency of less than 5.0 Hz and close to the average for the entire suite of ground motions for structures with frequencies greater then 5.0 Hz.


2014 ◽  
Vol 78 (2) ◽  
pp. 889-905 ◽  
Author(s):  
Sang Whan Han ◽  
Seong Jin Ha ◽  
Seung Wook Seok

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Binod Adhikari ◽  
Subodh Dahal ◽  
Monika Karki ◽  
Roshan Kumar Mishra ◽  
Ranjan Kumar Dahal ◽  
...  

AbstractIn this paper, we estimate the seismogenic energy during the Nepal Earthquake (25 April 2015) and studied the ground motion time-frequency characteristics in Kathmandu valley. The idea to analyze time-frequency characteristic of seismogenic energy signal is based on wavelet transform which we employed here. Wavelet transform has been used as a powerful signal analysis tools in various fields like compression, time-frequency analysis, earthquake parameter determination, climate studies, etc. This technique is particularly suitable for non-stationary signal. It is well recognized that the earthquake ground motion is a non-stationary random process. In order to characterize a non-stationary random process, it is required immeasurable samples in the mathematical sense. The wavelet transformation procedures that we follow here helps in random analyses of linear and non-linear structural systems, which are subjected to earthquake ground motion. The manners of seismic ground motion are characterized through wavelet coefficients associated to these signals. Both continuous wavelet transform (CWT) and discrete wavelet transform (DWT) techniques are applied to study ground motion in Kathmandu Valley in horizontal and vertical directions. These techniques help to point out the long-period ground motion with site response. We found that the long-period ground motions have enough power for structural damage. Comparing both the horizontal and the vertical motion, we observed that the most of the high amplitude signals are associated with the vertical motion: the high energy is released in that direction. It is found that the seismic energy is damped soon after the main event; however the period of damping is different. This can be seen on DWT curve where square wavelet coefficient is high at the time of aftershock and the value decrease with time. In other words, it is mostly associated with the arrival of Rayleigh waves. We concluded that long-period ground motions should be studied by earthquake engineers in order to avoid structural damage during the earthquake. Hence, by using wavelet technique we can specify the vulnerability of seismically active region and local topological features out there.


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