Application of ARMA models to estimate earthquake ground motion and structural response

2013 ◽  
Vol 470 ◽  
pp. 240-243 ◽  
Author(s):  
Jeng Hsiang Lin

Engineers are well aware that, due to the stochastic nature of earthquake ground motion, the information obtained from structural response analysis using scant records is quite unreliable. Thus, providing earthquake models for specific sites or areas of research and practical implementation is essential. This paper presents a procedure for the modeling strong earthquake ground motion based on autoregressive moving average (ARMA) models. The Generalized autoregressive conditional heteroskedasticity (GARCH) model is used to simulate the time-varying characteristics of earthquakes.


1989 ◽  
Vol 16 (5) ◽  
pp. 753-766 ◽  
Author(s):  
A. Filiatrault ◽  
S. Cherry

This paper is concerned with a study of the parameters influencing the seismic design of structures fitted with friction dampers. For the efficient design of such systems, the slip load distribution which minimizes structural response during a major earthquake must be determined for the dampers; this distribution is referred to herein as the optimum slip load distribution. A simple procedure is presented for establishing this basic design parameter. An analogy is first made between a single-storey friction damped structure and a simple nonlinear mechanical system. The response of this system to sinusoidal base excitation is then computed using an existing analytical solution. The solution clearly shows that the optimum slip load of the analogous friction damped structure depends on the amplitude and frequency of the ground motion and is not strictly a structural property. By extension, the optimum slip load distribution of a multistorey friction damped structure will be influenced by the characteristics of the earthquake ground motion anticipated at the construction site. Using this information, numerical sensitivity and parametric studies are performed on multistorey friction damped structures excited by a large number of artificial accelerograms generated from an existing stochastic earthquake model. The results of the study lead to the construction of a design slip load spectrum for the rapid evaluation of the optimum slip load distribution in a multistorey friction damped structure. The spectrum takes into account the properties of the structure and of the ground motion anticipated at the construction site and greatly simplifies the seismic design of this new structural system. Key words: braced frames, brake lining, design, damping, dynamics, earthquakes, energy, friction, slip load spectrum.


1953 ◽  
Vol 43 (2) ◽  
pp. 97-119
Author(s):  
G. W. Housner ◽  
R. R. Martel ◽  
J. L. Alford

Abstract The problem of the dynamic response of a structure to earthquake ground motion has been formulated in a manner which permits separation of the characteristics of particular structures from the characteristics of the earthquake. The expression involving the characteristics of the earthquake is defined as the “spectrum” of the earthquake and it is shown that the spectrum is a plot of the maximum response of a simple oscillator versus the period of the oscillator. Eighty-eight such spectra were computed by means of an electric analog computer and are presented in this paper. It is found that damping is a very important parameter in the over-all problem; relatively small amounts of damping reduce the structural response sharply. Further research on damping in buildings is recommended, and it is also proposed that the spectrum be used as a quantitative measure of earthquake intensity.


2011 ◽  
Vol 418-420 ◽  
pp. 1786-1795
Author(s):  
Abderrazak Menasri ◽  
Malek Brahimi ◽  
Abderrahmane Bali

The acceleration record of an earthquake ground motion is a nonstationary process with both amplitude and frequency content varying in time. The paper presents a general procedure for the analysis and simulation of strong earthquake ground motions based on parametric ARMA models. Structural design spectra are based on smoothed linear response spectra obtained from different events scaled by their peak values. Such an approach does not incorporate other characteristics of the excitation represented by measured data. This study investigate the use of non-stationary models which can be considered characteristic and representative of specific historical earthquakes. An earthquake record is regarded as a sample realization from a population of such samples, which could have been generated by the stochastic process characterized by an Autoregressive Moving Average (ARMA) model. This model is capable of reproducing the nonstationary amplitude as well as the frequency content of the earthquake ground accelerations. The moving time-window technique is applied to synthesize the near field earthquakes, Boumerdes-1, Boumerdes -2, and Boumerdes -3 2003 recorded on dense soils in Algeria. This model, is based on a low-order, time-invariant ARMA process excited by Gaussian white noise and amplitude modulated using a simple envelope function to account for the non-stationary characteristics. This simple model gives a reasonable fit to the observed ground motion. It is shown that the selected ARMA (2,1) model and the algorithm used for generating the accelerograms are able to preserve the features of the real earthquake records with different frequency content. In this evaluation, the linear and non linear responses of a given soil layer have been adopted. This study suggests the ability to characterize the earthquake by a minimum number of parameters.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
G. Tecchio ◽  
M. Grendene ◽  
C. Modena

This study carries out a parametrical analysis of the seismic response to asynchronous earthquake ground motion of a long multispan rc bridge, the Fener bridge, located on a high seismicity area in the north-east of Italy. A parametrical analysis has been performed investigating the influence of the seismic input correlation level on the structural response: a series of nonlinear time history analyses have been executed, in which the variation of the frequency content in the accelerograms at the pier bases has been described by considering the power spectral density function (PSD) and the coherency function (CF). In order to include the effects due to the main nonlinear behaviours of the bridge components, a 3D finite element model has been developed, in which the pounding of decks at cap-beams, the friction of beams at bearings, and the hysteretic behaviour of piers have been accounted for. The sensitivity analysis has shown that the asynchronism of ground motion greatly influences pounding forces and deck-pier differential displacements, and these effects have to be accurately taken into account for the design and the vulnerability assessment of long multispan simply supported bridges.


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