cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25549/uscfac-m57
title: Statistical analysis of response spectra method in earthquake engineering, 1987
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 87-03

description: A response spectrum superposition technique is often used to study the structural response to strong earthquake excitation. However, in its present form this technique can provide only the highest peak of the response at various levels of a multi-story structure. For better understanding of the progressing damage, as the structure is subjected to successive excursions beyond the design level, and to estimate the number of times certain responses may be exceeded, it is essential to know all the peaks of the response, not just the highest peak. In the present work, a probabilistic theory has been developed, using order statistics, to find the expected, the most probable, or with any desired confidence level, the amplitudes of all the local maxima in the random response functions are defined in terms of the parameters a sub rms (root-mean-square amplitude), ε (a measure of the width of energy spectrum), and N (total number of peak of response), all of which have been defined in terms of the modal properties of the structure and the Fourier and the response spectrum amplitudes of the input accelerograms. Theoretical relations have been formulated to study the response peaks of multi-story structures under excitations by a single translational component of ground acceleration, by all the three translational components of motion acting simultaneously, by torsional ground acceleration, and by the rocking acceleration of the ground. Application to a simple hypothetical three story structure shows good agreement with the time history solutions for all orders of peaks.
DOI: 10.25549/uscfac-m31
title: The effects of the wave passage on the response of base-isolated buildings on rigid embedded foundations, 1993
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 93-10

description: In this report, the response in the frequency domain is studied for a building on rubber bearings subjected to incident plane P- and SV-waves and surface Rayleigh waves. A simple two dimensional soil-structure model is used, in which the building is represented by an equivalent single degree-of-freedom (SDOF) oscillator or a uniform shear beam, on a circular rigid foundation, which is embedded into a homogeneous elastic half-space. The soil-structure interaction is included. For simplicity, all the deformations are assumed to be in linear range. The response of this model is compared with the response of the commonly used fixed-base model.; It is concluded that, as a result of the soil-structure interaction, the relative building response is further reduced, but the overturing moment of the inertia forces of the building about its base is significantly larger, because of the larger rocking amplitudes of the foundation. Also, it is shown that, for incident waves for which the foundation input motion has considerable amount of rocking, relative to the amplitudes of the horizontal motion, the transfer function amplitudes of the relative building response are larger at the frequency of the second mode, than at the first mode. The opposite trend is noticed for isolated buildings on a rigid base.
DOI: 10.25549/uscfac-m29
title: Earthquake response of arch dams to nonuniform canyon motion, 1988
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 88-03

description: A numerical procedure is developed for the earthquake response analysis of concrete arch dams to nonuniform accelerations and displacements of the canyon walls. The isoparametric finite elements are applied for modeling of the dam. Interaction between the dam and foundation can be accounted for by taking a portion of the foundation rock discretized by finite elements. Influence of the reservoir during the dam response is approximated by the added-mass of the incompressible water according to the generalized Wetsergaard formula. The nonuniform, free-field canyon motion is obtained by solving the two-dimensional wave equation via Bessel and Hankel function expansions. The boundary conditions are satisfied exactly on the flat surfaces outside the canyon walls and approximately, ie., at the finite number of points along the canyon walls. The motions of canyon during an earthquake are analyzed for the plane, body SH-, P-, and SV-waves as well as for the surface Rayleigh waves. For defined nonuniform motion of the canyon walls the response of the dam is computed in the time domain.; The response of the idealized arch dam Type 5 is investigated in detail and possible effects caused by the wave propagation across the canyon are shown. The results demonstrate that the motion of the canyon and consequently the response of the dam are highly dependent on the kind and on the angle arrival of the earthquake waves. The dynamic stresses in the dam can be much larger and with different distribution than the corresponding stresses caused by the uniform canyon motions. The quasi-static stresses induced by the nonuniform canyon displacement can be very significant and in many cases larger than the stresses caused by the inertial forces during the dynamic response of the dam. These stresses are distributed in the zones of the dam abutments indicating that the dam supports can be seriously damaged during the largest nonuniform displacements of the canyon walls.
DOI: 10.25549/uscfac-m40
title: Investigation of building responses to translational and rotational earthquake excitations, 1989
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 89-02

description: Current design practices for the multistoried buildings ignore the presence of rotational components in the earthquake ground motion, though no substantial research has, so far, been done to validate this. An existing lack of recorded accelerograms for these rotational components has largely been responsible for the absence of significant efforts in this direction. Some of the recent developments in the generation of synthetic accelerograms have made it possible now to seriously consider this aspect in the seismic design of multistoried buildings.; A probabilistic approach based on the response spectrum superposition technique has been formulated for the building response to the earthquake excitation comprised of the rotational components along with the translational component. This approach is different from the other methods of spectrum superposition, as it can account for the interaction between various modes of vibration and further, the response peaks of all orders can be estimated with a reasonable degree of accuracy for the given level of confidence. The formulation has been presented first for the fixed base buildings and then, it has been suitably modified to account for the effects of soil-structure interaction.; Through several example buildings and different earthquakes and sites, it has been shown that there are certain situations in which, neglecting the rocking component may lead to unsafe designs. Effects of the torsional component on the. overall building response, on the other hand, have been found to be small.
DOI: 10.25549/uscfac-m22
title: Analytical model for in plane building-foundation-soil interaction: incident p-, sv- and rayleigh waves, 1990
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 90-01

description: Foundation-soil and building-foundation-soil interaction has been studied using a two-dimensional analytical model, including both the dynamic and the kinematic interaction effects. The building has been represented by an infinitely long shear wall resting on a rigid circular foundation, embedded into an elastic homogeneous half-space. Deep and shallow foundations have been considered (with depth-to-half-width ratio of 1 and 0.5) and excitation consisting of plane P- and SV- and surface Rayleigh waves. The wave function expansion method has been used to represent the motion in the half-space and a substructure approach to solve the interaction problem. Special attention has been paid to the wave passage effects, and to the influence of the depth of the embedment.
DOI: 10.25549/uscfac-m25
title: Broad band extension of pseudo relative velocity spectra of strong ground motion, 1994
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 94-02

description: This report reviews the physical bases and the observations of strong earthquake ground motion for quantitative extrapolation of pseudo relative velocity spectral amplitudes to long (T &gt; 10 sec) and to short (Y &lt; .04 sec) periods. This will serve as a basis for subsequent use of these scaling equations in hazard calculations in the same broad frequency band. At present, empirical scaling equations of response spectrum amplitudes are limited to periods between .04 and several seconds. The design of long structures and of structures on multiple distant supports requires knowledge and specification of design ground motions well beyond this frequency range. This report addresses the first approximate extrapolation of the available response spectrum amplitudes, and deals with formulation of the physical basis for such extrapolation.
DOI: 10.25549/uscfac-m44
title: Investigation of numerical methods in inversion of earthquake source, 1986
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 86-01

description: The inverse problem with an application to the earthquake source inversion has been investigated. The kinematical model is used to describe the earthquake source and the Body Force Equivalent (B.F.E.) is considered as a mathematical model in the inversion. It is shown that the integral part representation of the source radiation, due only to displacement discontinuity, is independent of the force behavior at the fault. Also, the presence of subsequent force discontinuity will not affect the integral representation. Under the assumption of force continuity, it is shown that the dislocation vector is the eigenvalue solution of a certain linear operator.; To obtain a solution a least-squares technique has been employed. The least squares (LSQ) approach has been investigated in some detail from both the theoretical and the numerical point of view. Tikhonov regularization has been employed to provide a stable and meaningful solution. The regularization error and the rate of convergence are also discussed.; The theoretical results have been implemented into a practical application through Singular Value Decomposition (S.V.D) of the LSQ system matrix. For the purpose of source inversion the LSQ model is improved by introducing shifting optimization. Based on the spatial properties of dislocation, expansion of the dislocation into a series of an appropriately chosen set of functions is also presented.; As an application, the source inversion for the Imperial Valley earthquake of 1979 in California is presented. Detailed discussions and comparison are included between different LSQ models. Also, the effects of different regularization parameters on the dislocation have been considered.
DOI: 10.25549/uscfac-m32
title: Empirical equations describing attenuation of peaks of strong ground motion, in terms of magnitude, distance, path effects and site conditions, 1995
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 95-02

description: In this report we present amplitude attenuation equations for peaks of strong motion acceleration, velocity and displacement. These equations depend on magnitude scale, M, representative distance to the fault, ∆, fault length, type of propagation path and fraction of epicentral distance travelled through basement rocks (0 &lt; r &lt; 1). Near the recording station, the local geological conditions can be characterized either by the geologic site parameters s (distinguishing between sediments and basement rock) or by the depth of sediments, h. the local soil conditions are described by the local soil conditions are described by the local soil parameter s sub L (distinguishing rock, stiff and deep soil conditions). We examined the relative significance of the common site parameters, which are used to describe the site specific amplitudes of strong motion amplitudes. We found that the average velocity of the shear waves in the top 30 m below ground surface is not a significant parameter influencing the peak amplitudes of acceleration, velocity and displacement.
DOI: 10.25549/uscfac-m51
title: A preliminary study of the duration of strong earthquake ground motion on the territory of former Yugoslavia, 1993
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 93-09

description: This report presents an empirical study of frequency dependent duration of strong earthquake ground motion on the territory of former Yugoslavia, using a uniformly processed database of 330 three-component accelerograms from 183 earthquakes, recorded at 60 sites in former Yugoslavia between 1975 and 1984. The duration is studied in 12 narrow frequency bands (channels). In each channel, the acceleration and corresponding velocity and displacement time histories are considered as one homogeneous data set. The duration of the strong motion part in a function f(t) of ground motion (acceleration, velocity or displacement) is defined in each frequency band as the sum of the time intervals during which the integral graph of the function f(τ)dτ between τ=0 and τ=t has the fastest growth and gains 90% of its final value. In each frequency band, the duration is modeled as a sum of two terms, the "basic duration" -- the duration of strong motion observed at rock sites, and the "site conditions" term -- prolongation due to specific geological and local soil conditions at the recording site. Two groups of empirical models are studied, one with the earthquake magnitude and the other one with the site intensity as a scaling parameter. An algorithm is presented for choosing a model depending on which earthquake and site parameters are available for a particular application. The results also includes probability distribution functions for the residuals of the models, which allows one to estimate the probability of a given duration at a site being exceeded, given the earthquake size and location (or site intensity) and the local site conditions.; The Yugoslav database is deficient in records from large magnitude earthquakes, and in records at sites on basement rock (geological classification) and on deep soil (local soil classification). Also, for many records the contributing earthquakes have not been identified, which reduced further the number of records that could be used. Consequently, independent development of regression models using only this database was not possible. Instead, models developed earlier by the authors for the Western U.S. using a more complete database were fit to the Yugoslav data.; The major trends in the regression models for the Western United States and for former Yugoslavia are the same, but there are some differences. In the Yugoslav models, the duration grows with magnitude at a higher rate for large magnitude earthquakes and at high frequencies. Also, the increase of duration with distance from the source is smaller. These differences and the pattern of the dependence of duration on intensity support the assumption of larger wave velocities and larger quality factor Q in the upper crust on the territory of former Yugoslavia than in the Western United States.
DOI: 10.25549/uscfac-m41
title: Investigation of earthquake response of long buildings, 1988
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 88-02

description: In this work the physical phenomena associated with the wave passage under long buildings have been studied. Two-dimensional, Continuous models have been used to represent the building vibration. Buildings without major discontinuities, with shear walls at the ends, with a central core and with a soft first floor have been considered. Analytical, closed form solutions have been obtained for the response to incident monochromatic, plane SH waves. The soil-structure interaction has been neglected.; Response of a building to a translational and rotational excitation has been calculated also, as an approximation when the ratio between the length of the building and the apparent wave length of the ground wave in the horizontal direction is very small.; Methods of computation of the response to realistic ground motion have been suggested, for different forms of incident waves and in terms of Fourier synthesis.
DOI: 10.25549/uscfac-m37
title: Influence of local soil and geologic site conditions on fourier spectrum amplitudes of recorded strong motion accelerations, 1987
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 87-04

description: The idea that the local soil and geological site conditions may influence the amplitudes of recorded seismic waves has been around for many years and has been investigated by many researchers. This has been studied theoretically (e.g. Haskell, 1960; Tsai, 1969; Trifunac, 1971) and experimentally (e.g. Kanai, 1949,'1957; Gutenberg, 1957; Duke, 1958; Medvedev, 1955) by considering various overall measures of strong shaking or its effects on different types of structures. Beginning in the 1960's and 1970's these studies took on more detailed and more complete nature because of the increased availability of recorded strong motion accelerograms. Through comparison of the shapes of the Fourier and response spectrum amplitudes, it became possible to describe the effects the local soil conditions have on the local site response (Seed et al., 1974) and to extend the results of Gutenberg (1957) about the effects of the local geologic conditions to the high frequency spectral amplitudes (Trifunac, 1976). Through the 1970's and early 1980' s these studies were further refined by detailed regression analyses which were made possible by still larger numbers of well documented records of strong ground motion (Trifunac, 1976,1979; Trifunac and Lee, 1987a,b,c).; However, to this date these studies considered either the local soil or the local geologic site conditions and never combined the simultaneous effects of both media in the development of one and more general scaling relation. Since the typical dimensions of the local soil versus the local geologic site conditions are so different one might expect that their effects would be reflected in the recorded spectral amplitudes in high and in low frequencies respectively. If both of these effects can be shown to contribute significantly to the variation of spectral amplitudes between 0.05 and 25 Hz, the frequency range of interest to earthquake engineering, then both soil and geologic site condition should be considered simultaneously. The purpose of this report is to investigate this and to find how these effects should be used in the empirical scaling of Fourier amplitude spectra.
DOI: 10.25549/uscfac-m38
title: Influence of local soil and geologic site conditions on pseudo relative velocity spectrum amplitudes of recorded strong motion accelerations, 1987
title: Civil Engineering Technical Report Series - Strong Motion Group Contributions CE 87-06

description: It is well recognized now that the soil and geologic site conditions modify the amplitudes and the duration of incident strong earthquake waves (Kanai, 1949,1957; Gutenberg, 1957; Duke, 1958; Medvedev, 1955; Tsai, 1969). This has been studied empirically (e.g. Trifunac 1971a,b; 1976a,b,c; 1978, 1979, 1980; Trifunac and Anderson 1977, 1978; Trifunac and Brady 1975a,b,c; Trifunac and Lee, 1978, 1979, 1987a,b; Trifunac and Udwadia, 1974; Trifuanc and Westenno, 1977, 1982; Udwadia and Trifunac, 1973 and Westenno and Trifunac, 1978) and theoretically (e.g. Moeen-Vaziri and Trifunac, 1987a,b; Trifunac, 1971, 1973; Wong and Trifunac, 1974 and Wong, et al. 1976). The overall effects of both soil and geological site conditions have been synthesized recently by Trifunac (1987).; One of the first studies which analyzed the effects of local soil conditions on the changes of the shape of the response spectrum has been carried out by Zhou (1965). This was followed by Seed et al. (1974, 1976), who analyzed. this effect quantitatively, by comparing the average spectrum shapes for four different classifications of the soil characteristics at the recording sites. The effects of the geological site characteristics were investigated by Gutenberg (1957) and by Trifunac (1976c).; The purpose of this report is to present an extension of the work of Trifunac (1987) to the scaling of the Pseudo Relative Velocity Spectra. Since the format of this work will follow closely that of Trifunac (1987), the reader may wish to peruse his results before proceeding to read this report. Furthermore, the reader will find many sections of this report to be repetitive in the format, style and details, as the reading progresses from Parts I into Parts II, III, IV and V. For completeness in presentation many equations and many plots have been repeated from one part of this work to the next. It was felt, however, that after the proper selection of the scaling models is done, some fine points, particularly some minor inconsistencies among different models might be "forgotten." Thus, every effort has been made to document all results, and to present all details as graphically as possible. The casual reader may wish, to glance over the end results, and to read the summary in Section V as well as the conclusions. The rest of this report should serve as a pictorial archive summary on the properties of our regression models for scaling the Pseudo Relative Velocity (PSV) response spectra, and may be helpful for the formulation of better regression models in future analyses.