bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seismic testing of large panel precast walls: Comparison of pseudostatic and shaking table tests
Authors: Oliva Michael , Gavrilovic Predrag , Clough Ray W. 
Published: April 2007

AbstractUrban housing has been provided economically in many parts of the world by large panel precast building systems; in seismic regions, however, special attention must be given to the connections between panels in order to achieve the necessary earthquake resistance. In this paper a comprehensive seismic test programme of concrete panel assemblages done as part of a U.S.‐Yugoslavia cooperative research plan in earthquake engineering is described. The test structures were three‐storey assemblages of 1/3 scale concrete panels supplied by a Yugoslavian construction company; the models were about 12 ft high and 6 ft long, with the panels interconnected by various types of joint systems along their tops, bottoms and sides.Cyclic pseudostatic testing of the models was done at the IZIIS Laboratories in Skopje, Yugoslavia. A second set of models was assembled at the University of California, Berkeley from identical panels that had been shipped from the Belgrade factory; these models were tested on the 20 ft square EERC shaking table. The purpose of this paper is to compare the earthquake response represented by the two different types of test procedures.A major conclusion was that the response mechanisms in both cases were similar, with the principal deformation being opening of the panel joint at the base of the model due to overturning moments. As the rocking response continued, tension and compression failure occurred alternately at the two ends of the joint. The principal difference between the results was that pseudostatic testing imposed an increasing sequence of symmetric deformation that was independent of the damage being developed in the model, while the shaking table response was greatly influenced by the damage as it occurred—leading to significant unsymmetry. Moreover, the damage occurred in a concentrated region with the shaking table test. This difference emphasizes the fact that pseudostatic test results must be interpreted with caution because they do not fully simulate an actual earthquake response.
Ritz method for dynamic analysis of large discrete linear systems with non‐proportional damping
Authors: Ibrahimbegovic Adnan , Chen Harn C. , Wilson Edward L. , Taylor Robert L. 
Published: April 2007

AbstractReal and complex Ritz vector bases for dynamic analysis of large linear systems with non‐proportional damping are presented and compared. Both vector bases are generated utilizing load dependent vector algorithms that employ recurrence equations analogous to the Lanczos algorithm. The choice of static response to fixed spatial loading distribution, as a starting vector in recurrence equations, is motivated by the static correction concept. Different phases of dynamic response analysis are compared with respect to computational efficiency and accuracy. It is concluded that the real vector basis approach is approximately eight times more efficient than the complex vector basis approach. The complex vector basis has some advantages with respect to accuracy, if the excitation is of piecewise linear form, since the exact solution can be utilized. In addition, it is demonstrated that both Ritz vector bases, real and complex, possess superior accuracy over the adequate eigenvector bases.
Regional seismic slope failure probability matrices
Authors: Lin Jeen‐Shang 
Published: April 2007

AbstractA method for constructing seismic slope failure probability matrices is presented. The core of the method is a probabilistic sliding block model which allows for systematic incorporation of the uncertainties associated with both the ground excitation and the strength of the slope materials. The extent of damage to a slope is defined in terms of the magnitude of the earthquake‐induced permanent displacement. The intensity of the ground shaking is characterized by a peak ground acceleration as well as an earthquake magnitude, and the possible scatter in the ground motion details is included through the use of an equivalent stationary motion model. After the effects of essential contributing factors are discussed, regional seismic slope failure probability matrices are presented for general applications.
A simple boundary element formulation and its application to wavefield excited soil‐structure interaction
Authors: Auersch L. , Schmid G. 
Published: April 2007

AbstractA simple boundary element formulation which is based directly on the point load solutions for an elastic full‐space is presented. It is integrated in a finite element program to calculate dynamic soil‐structure interaction problems. The combined boundary and finite element method is applied to structures which are excited by horizontally propagating waves in the soil.For three different types of flexible structure‐elastic beams, low and high (square) shear walls‐and the corresponding rigid structures the vibration modes and the soil‐structure transfer functions have been investigated. The flexible foundations display the same wave pattern as the exciting free‐field of the soil, but the amplitudes are reduced with increasing frequency, depending on the stiffness or wave resistance of the structure. Rigid structures show, in part, quite different behaviour, giving free‐field reductions caused by kinematic and inertial soil‐structure interaction.
Analysis of saturated dense sand‐structure system and comparison with results from shaking table test
Authors: Fukutake Kiyoshi , Ohtsuki Akira , Sato Masayoshi , Shamoto Yasuhiro 
Published: April 2007

AbstractAn effective stress method is presented for the analysis of liquefaction of ground including soil‐structure interaction, based on an explicit‐implicit finite element method. A simple constitutive model is developed to be incorporated in the effective stress method. The constitutive model consists of the Ramberg‐Osgood model extended to two‐dimensional problems and a new dilatancy model. The effectiveness of the constitutive model is examined with results of a simple shear test. Besides, the effective stress method is verified by comparing its numerical results with results of a shaking table test. It is found that the present method can simulate well the response of a saturated dense sand‐structure system. The difference of the response computed by the effective stress method and the total stress method is discussed. It is found that the total stress method can simulate the response of the saturated sand within an accumulating excess pore water pressure of less than 70 per cent of the initial overburden stress.
The many steady state responses of a rigid block under harmonic forcing
Authors: Hogan S. J. 
Published: April 2007

AbstractRecent mathematical advances in the study of the response of a rigid block to horizontal simple harmonic forcing conclude that (i) all types of subharmonic response are possible, (ii) several types can occur at one point in parameter space, (iii) exact expressions are available for stability boundaries in parameter space, (iv) asymmetric solutions exist just outside the upper boundaries of symmetric solutions, (v) period‐ and impact‐doubling cascades occur as parameter values are varied even further outside the boundaries, (vi) aperiodic (or chaotic) responses are possible, (vii) periodic responses can occur which appear to violate West's formula and (viii) steady state responses of the forced system can be so large as to produce toppling of the block if the system were unforced.These results are used to explain and extend recent computational work. Also we find quantitative agreement between our theoretical work and some recent experimental work of Tso and Wong.
A strong motion database for the chiba seismometer array and its engineering analysis
Authors: Katayama Tsuneo , Yamazaki Fumio , Nagata Shigeru , Lu Lin , Turker Turgay 
Published: April 2007

AbstractA three‐dimensional seismometer array was installed in the Chiba Experiment Station of the Institute of Industrial Science, University of Tokyo in 1982. The array system consists of 44 three‐component accelerometers densely placed both on the ground surface and in boreholes. A complementary system for the measurement of ground and buried pipe strains was also installed at the same site. The array system has been successfully in operation, and more than 160 earthquakes have been recorded. Considering a wide use of these seismograms, the Chiba array database has recently been created comprising twenty‐seven major events. This paper describes the Chiba array system and its strong motion database. Results of engineering analysis using the selected records are also presented.
Attenuation models inferred from intraplate earthquake recordings
Authors: Dahle Anders , Bungum Hilmar , Kvamme Leif B. 
Published: April 2007

AbstractStrong‐motion recordings at 87 sites from 56 different intraplate earthquakes from North America, Europe, China and Australia have been used through a two‐step regression analysis to develop new attenuation models for peak ground acceleration, and for pseudo‐relative velocity for frequencies of 0.25, 0.5, 1.0, 2.0, 5.0 and 10.0 Hz, all for 5 per cent of critical damping. The estimates are obtained along with an analysis of residuals and scatter.A similar regression analysis has been performed also for Fourier spectra of acceleration, in which case the coefficient for the anelastic term has been interpreted in terms of a frequency dependent quality factor Q. The resulting Q‐model shows a strong frequency sensitivity with values around 600–700 at 1 Hz, around 2000 at 10 Hz and around 5200 at 25 Hz.These PGA, PSV and Q results depend, however, on the underlying assumption for geometrical spreading, in particular for low frequencies.
Investigation of the dynamic interaction between a high‐pressure pipeline and the moving liquid inside under seismic loading
Authors: Kisliakov Dimiter 
Published: April 2007

AbstractThe response of an open high‐pressure pipeline containing moving liquid to horizontal seismic loading is investigated. The problem of the interaction between the pipe and the liquid inside it is solved after thorough kinematic analysis, involving two‐stage application of the Coriolis theorem. The basic axial loading on the pipeline is also taken into account. As a result, the equation of motion of an arbitrary one‐span part of the pipeline under seismic loading is obtained. The harmonic balance is used to find the solution. As an illustration to the theory a numerical example is given with the data of a real water power station pressure pipeline under a past earthquake record.
Consistent lumped‐parameter models for unbounded soil: Frequency‐independent stiffness, damping and mass matrices
Authors: Wolf John P. 
Published: April 2007

AbstractA systematic procedure to develop consistent (symmetric) stiffness, damping and mass matrices with real coefficients to represent any unbounded soil is developed. These property matrices are based on the lumped‐parameter models of Reference 1. Either stiffness and damping matrices corresponding to first‐order differential equations involving the internal degrees of freedom and those on the structure‐soil interface result or, alternatively, in addition mass matrices are introduced, corresponding to second‐order differential equations, which reduce the number of internal degrees of freedom by a factor 2.The stiffness, damping and mass matrices can easily be incorporated in a general‐purpose structural dynamics program working in the time domain, whereby the structure can even be non‐linear.
A method to estimate intensity occurrence probabilities in low seismic activity regions
Authors: Egozcue J. J. , Barbat A. , Canas J. A. , Miquel J. , Banda E. 
Published: April 2007

AbstractThe estimation of site intensity occurrence probabilities in low seismic activity regions has been studied from different points of view. However, no method has been definitively established because several problems arise when macroseismic historical data are incomplete and the active zones are not well determined. The purpose of this paper is to present a method that estimates site occurrence probabilities and at the same time measures the uncertainties inherent in these probabilities in low activity regions. The region to be studied is divided into very broad seismic zones. An exponential intensity probability law is adjusted for each zone and the degree of uncertainty in the assumed incompleteness of the catalogue is evaluated for each intensity. These probabilities are used to establish what may be termed ‘prior site occurrence models’. A Bayesian method is used to improve ‘prior models’ and to obtain the ‘posterior site occurrence models’. Epicentre locations are used to recover spatial information lost in the prior broad zoning. This Bayesian correction permits the use of specific attenuation for different events and may take into account, by means of conservative criteria, epicentre location errors. Following Bayesian methods, probabilities are assumed to be random variables and their distribution may be used to estimate the degree of uncertainty arising from (a) the statistical variance of estimators, (b) catalogue incompleteness and (c) mismatch of data to prior assumptions such as Poisson distribution for events and exponential distribution for intensities. The results are maps of probability and uncertainty for each intensity. These maps exhibit better spatial definition than those obtained by means of simple, broad zones. Some results for Catalonia (NE of Iberian Peninsula) are shown.
Inelastic seismic response of one‐storey, asymmetric‐plan systems: Effects of system parameters and yielding
Authors: Goel Rakesh K. , Chopra Anil K. 
Published: April 2007

AbstractThe inelastic response of one‐storey, asymmetric‐plan systems to two excitations is presented and analysed with the objective of identifying the influence of system parameters: uncoupled lateral vibration period, uncoupled torsional‐to‐lateral frequency ratio, stiffness eccentricity, relative values of the strength and stiffness eccentricities, and yield factor. Furthermore, the influence of yielding on the response of asymmetric‐plan systems is examined. In particular, we determine whether the well known relationship between the response of yielding and elastic single‐degree‐of‐freedom (SDF) systems is also applicable to asymmetric‐plan systems.
Dynamic response of buildings due to trains in underground tunnels
Authors: Balendra T. , Koh C. G. , Ho Y. C. 
Published: April 2007

AbstractThe interaction of a tunnel‐soil‐building system due to trains is investigated by a substructure technnique. The soil medium is assumed to be a viscoelastic halfspace. The method of wave function expansion is used to construct the displacement fields in terms of potentials. The total soil‐structure interaction problem is decomposed into a foundation radiation problem and a tunnel radiation problem. The impedance matrices for the corresponding substructure problems are obtained using a collocation technique. The steady state response of buildings for a given tunnel‐foundation geometry is determined using the impedance matrix. Hence, the response of the building to train loading at different speeds is evaluated and compared with allowable vibration limits.
Earthquake induced hydrodynamic pressure on axisymmetric offshore structures
Authors: Sun Keming , Nogami Toyoaki 
Published: April 2007

AbstractThe horizontal earthquake induced hydrodynamic pressure acting on the surface of axisymmetric offshore and coastal structures is explored. A semi‐analytical and semi‐numerical approach based on the use of a complete and non‐singular set of Trefftz functions is developed. Using this method, one can model accurately the compressibility of the sea water and gravity waves on the water surface. The proposed method shows a relatively simple and efficient approach. This is because the number of degrees of freedom in the matrix equation depends only on the number of selected Trefftz functions and because the discretization of the fluid domain into boundary elements is restricted to the structural surface only. This method is also easy to apply in engineering analysis of hydrodynamic pressure induced by an actual earthquake acceleration. Numerical examples are presented to illustrate the results obtained from this method. Several special interesting topics, such as the effects of the water compressibility, the gravity waves on the water surface and the geometrical shape of the structural surface, are also discussed.
Dynamic interaction between flexible strip foundations
Authors: Wang Y. , Rajapakse R. K. N. D. , Shah A. H. 
Published: April 2007

AbstractThis paper is concerned with the dynamic response of a system of flexible strip foundations resting in smooth contact with a homogeneous isotropic viscoelastic half space. An arbitrary number of foundations with different flexibilities and geometries subjected to time‐harmonic distributed loadings are considered in the formulation. The response of each strip foundation is governed by the classical plate theory and its transverse deflection is represented by an admissible function containing a set of generalized co‐ordinates. A coupled variational‐Green's function scheme is employed to establish the equations of motion of the strip foundation system. The numerical stability and convergence of the solution scheme are established. The influence of the foundation flexibility, distance between adjacent foundations and frequency of motion on the response of the foundation system is investigated in the numerical study.
An assessment of seaonc draft code for resilient sliding isolators
Authors: Mostaghel N. , Mortazavi A. R. 
Published: April 2007

AbstractThe displacement responses of rigid structures supported on resilient sliding isolation systems with various frictions to six different ground motions normalized to ground velocity levels from 1 to 25 in per sec are evaluated. Through the application of an equivalent damping procedure, the minimum required displacement capacities as dictated by the SEAONC draft code are also estimated. It is concluded that, even though the code displacement requirement is on the conservative side, the displacement capacity requirement is not excessive.
Dynamic behaviour of R/C highway bridges under the combined effect of vertical and horizontal earthquake motions
Authors: Saadeghvariri M. Ala , Foutch D. A. 
Published: April 2007

AbstractMeasurements of ground motions during past earthquakes indicate that the vertical acceleration can reach values comparable to horizontal accelerations or may even exceed these accelerations. Furthermore, measurements of structural response show the possibility of significant amplification in the response of bridges in the vertical direction that can be attributed to the vertical component of ground motion. In this study, the relative importance of the vertical component of ground motion on the inelastic response of R/C highway bridges is investigated. Particular emphasis is placed on modelling of the deck and piers to account for complex loading histories under combined vertical and horizontal earthquake motions. Analyses of actual bridges indicate that, in general, the vertical motion will increase the level of response and the amount of damage sustained by a highway bridge. Vertical motion generates fluctuating axial forces in the columns, which cause unstability of the hysteresis loops and increase the ductility demand. Furthermore, vertical motion can generate forces of high magnitude in the abutments and foundations that are not accounted for by the current seismic design guidelines. Thus, it is important to consider this component of the ground motion in the design of highway bridges, especially for those located in regions near seismic faults.
Periodic response of a rigid block resting on a footing subjected to harmonic excitation
Authors: Matsui Kunihito , Iura Masashi , Sasaki Toshimi , Kosaka Iku 
Published: April 2007

AbstractThis study presents the dynamic behaviour of a rigid block which rests on a footing supported by a spring and a dashpot on a rigid base. The response of the rigid body is examined carefully when the base is excited by a harmonic force. It is found that a periodic motion appears in three different modes: stick‐stick, stick‐slip and slip‐slip. The conditions that initiate the stick‐stick and slip‐slip modes are derived in explicit forms and the maximum sliding displacement is also obtained analytically. Useful dimensionless parameters are proposed for the presentation of the dynamic behaviour. The accuracy of results is confirmed by the response history computed by the Nigam‐Jennings method.
Ambient vibration measurements on a cable‐stayed bridge
Authors: Wilson John C. , Liu Tao 
Published: April 2007

AbstractAn extensive programme of full‐scale ambient vibration tests has been conducted to measure the dynamic response of a 542 m (centre span of 274 m) cable‐stayed bridge—the Quincy Bayview Bridge in Illinois. A microcomputer‐based system was used to collect and analyse the ambient vibration data. A total of 25 modal frequencies and associated mode shapes were identified for the deck structure within the frequency range of 0–2 Hz. Also, estimations were made for damping ratios. The experimental data clearly indicated the occurrence of many closely spaced modal frequencies and spatially complicated mode shapes. Most tower modes were found to be associated with the deck modes, implying a considerable interaction between the deck and tower structure. No detectable levels of motion were evident at the foundation support of the pier. The results of the ambient vibration survey were compared to modal frequencies and mode shapes computed using a three‐dimensional finite element model of the bridge. For most modes, the analytic and experimental modal frequencies and mode shapes compare quite well, especially for the vertical modes. Based on the findings of this study, a linear elastic finite element model appears to be capable of capturing much of the complex dynamic behaviour of the bridge with very good accuracy, when compared to the low‐level dynamic responses induced by ambient wind and traffic excitations.
Control of seismic response of turbomachin foundations
Authors: Pantelides C. P. 
Published: April 2007

AbstractThe safety of structures built in seismic regions can be improved by energy absorbing devices. Passive isolation systems such as base isolators are suitable for low‐rise structures, but they provide only a partial solution to the problem. Three active control techniques for reducing the dynamic response of machine supporting foundations using various control strategies are presented. The active tendon, active mass damper and active base control systems are studied for active control of machine foundations in seismic regions. Numerical simulations show that active control can reduce the dynamic response of turbomachine foundations under seismic loads. This reduction in dynamic response can limit damage to power plants during earthquakes and restore their operation in a short time.