摘要:

AbstractGenerally, waves in layered media include several surface wave modes showing dispersive properties. These properties often complicate the understanding of the propagation characteristics of elastic waves. In this paper, not only a method for decomposing transient elastic waves into normal modes is presented but also investigations are applied to decomposed normal modes. This method is developed by means of DWFE and the modal superposition method. In the formulation process, transfer functions describing the relationship between the amplitude of normal modes and that of force density are defined. It was found that the propagation properties of the normal modes were well explained by the dispersion curves and transfer functions. From investigations of the normal mode propagation, properties of each normal mode can be discussed.

ISSN:0098-8847    

DOI:10.1002/eqe.4290240702

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper deals with the use of ARMA models in earthquake engineering. Tools and methods applied to strong ground motion are discussed emphasizing simulation of probabilistic earthquake response spectra. The ARMA models are applied to Icelandic earthquake data and a tentative model for Icelandic earthquakes is presented. This model, which is derived using 54 accelerograms, 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. Further, this model produces accurate earthquake response spectra, which, combined with accompanying attenuation and duration formulae, might be useful in earthquake hazard and risk asses

ISSN:0098-8847    

DOI:10.1002/eqe.4290240703

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractLiquid motions in shallow Tuned Liquid Dampers (TLDs) with rectangular, circular, and annular tanks, subject to harmonic base excitation, are measured experimentally. Using a Single‐Degree‐of‐Freedom (SDOF) Tuned Mass Damper (TMD) analogy, equivalent mass, stiffness and damping of the TLD are calibrated from the experimental results. These parameters are functions of the TLD base amplitude. Some important properties of the TLD are discussed on the basis of these re

ISSN:0098-8847    

DOI:10.1002/eqe.4290240704

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe free‐field accelerograms along Feitsui Canyon are analysed and modelled by a numerical scheme to study the effect of canyon topography. Six strong‐motion accelerometers (SC1–SC6) were deployed along the Feitsui Canyon in 1991. The observations suggest that the amplitude of ground motion at the trough of the canyon is smaller than that on its slopes. The integral equation method is applied to a two‐dimensional model of Feitsui Canyon to study the effects of the canyon topography. We choose the ground motion of SC3 station at the trough of the canyon as the input motion to the model, which is then used to predict the ground motion at the other five stations. The simulated and observed seismograms agree well in displacement and velocity, although the simulated acceleration at high frequency is underestimated. The simple model can reproduce the observed accelerations at all frequencies bel

ISSN:0098-8847    

DOI:10.1002/eqe.4290240705

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA study of the response to horizontal ground shaking of a rigid cylindrical tank containing an inviscid liquid with a continuous vertical variation in density is presented. In addition to the free vibrational sloshing characteristics of the liquid, the responses examined include the vertical displacements at the free surface, and the impulsive and convective components of the hydrodynamic wall pressures and associated tank forces. The equations of motion for the system are formulated for an arbitrary variation in liquid density but the solutions presented are for a density that increases exponentially from top to bottom. Comprehensive numerical data are included which elucidate the underlying response mechanisms and the effects and relative importance of the various parameters involved. The solution for the continuous density variation considered herein is also compared with a previously reported solution in which the liquid was modelled as a multi‐layered, discrete syste

ISSN:0098-8847    

DOI:10.1002/eqe.4290240706

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe general time‐domain boundary element in cylindrical co‐ordinates developed for the study of wave propagation in a layered half‐space is extended to the response analysis of single piles under horizontal transient excitations. The pile is treated as a beam, and therefore, only the bending stiffness has to be considered in the analysis. As required by the non‐axisymmetric nature of the problem, the soil is modelled by boundary (cylindrical) elements with the vertical, radial and tangential displacements as well as their corresponding tractions as independent variables. The characteristic matrices for the two different types of element can be formed in the usual manner, and they are combined to form the equation of motion for the whole system by virtue of compatibility and equilibrium conditions along the pile‐soil interface. The transient responses of a pile under Heaviside loads are found to converge to the static values. Parametric studies are carried out to reveal the influences of pile‐soil stiffness ratio (Ep/Es) and so

ISSN:0098-8847    

DOI:10.1002/eqe.4290240707

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper proposes an aseismic design concept in which the superstructure of a base‐isolated building is divided into several segments. Each segment may comprise a few storeys and is interconnected by additional vibrational isolation systems. The dynamic characteristics of the segmental buildings are investigated. The optimum parameters of the vibration isolation systems are determined by minimizing the mean square acceleration response. The seismic response of a typical segmental building subjected to the N—S component of the 1940 El Centro earthquake input is evaluated and compared with the responses of the corresponding fixed‐base and conventional base‐isolated buildings. The comparisons show that, when the superstructure is segmented, while the acceleration response in the superstructure remains as small as that in the conventional base‐isolated building, the displacement across the base isolation system at foundation level is substantiall

ISSN:0098-8847    

DOI:10.1002/eqe.4290240708

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290240709

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290240710

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290240701

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY