摘要:

AbstractThe available substructure method and computer program for the steady‐state, harmonic response analysis of arch dams, including the hydrodynamic effects, are extended to consider flexibility of the foundation rock and to include Fourier synthesis of harmonic responses to obtain the earthquake response of arch dams. By efficient evaluation of hydrodynamic terms, interpolation of frequency response functions and more efficient computer programming, the computational costs for analysing arch dams have been reduced by an order of magnitude relative to the available procedur

ISSN:0098-8847    

DOI:10.1002/eqe.4290140202

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractProposed is a new definition of earthquake response spectra, which takes account of the number of response cyclesN.TheNth largest amplitude of absolute acceleration response of a linear oscilator with natural periodTand damping ratioh, which is subjected to ground motion at its base, is defined asSA(T,h,N). By defining a reduction factor η(T,h,N) asSA(T,h,N)/SA(T,h, 1), characteristics of η(T,h,N) were investigated based on 394 components of strong motion records obtained in Japan. Two practical empirical formulae to assess the reduction factor η(T,h,N) are propos

ISSN:0098-8847    

DOI:10.1002/eqe.4290140203

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper presents the result of multiple regression analysis of 197 sets of two orthogonal horizontal strong motion acceleration records. They were obtained at 67 free field sites in Japan from 90 earthquakes with focal depth less than 60 km. Because sensitivity of the Japanese SMAC accelerograph is appreciably low at the high frequency range, instrument correction was performed on the original data. Each pair of two orthogonal horizontal components was combined in the time domain to get the maximum peak ground motions in the horizontal plane.The records were classified into three groups due to subsoil condition. With the use of multiple regression analysis, empirical formulae of attenuation of the maximum peak ground acceleration, velocity and displacement were proposed for three subsoil conditions.

ISSN:0098-8847    

DOI:10.1002/eqe.4290140204

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA critical, textbook‐like review of the generalized modal superposition method of evaluating the dynamic response of nonclassically damped linear systems is presented, which it is hoped will increase the attractiveness of the method to structural engineers and its application in structural engineering practice and research. Special attention is given to identifying the physical significance of the various elements of the solution and to simplifying its implementation. It is shown that the displacements of a non‐classically dampedn‐degree‐of‐freedom system may be expressed as a linear combination of the displacements and velocities ofnsimilarly excited single‐degree‐of‐freedom systems, and that once the natural frequencies of vibration of the system have been determined, its response to an arbitrary excitation may be computed with only minimal computational effort beyond that required for the analysis of a classically damped system of the same size. The concepts involved are illustrated by a series of examples, and comprehensive numerical data for a three‐degree‐of‐freedom system are presented which elucidate the effects of several important parameters. The exact solutions for the system are also compared over a wide range of conditions with those computed approximately considering the system to be classically damped, and the interrelationship of two sets of s

ISSN:0098-8847    

DOI:10.1002/eqe.4290140205

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractFundamental principles from structural dynamics, theory of random processes and perturbation techniques are used to develop a new method for seismic analysis of multiply supported secondary subsystems, such as piping attached to primary structures. The method provides a decoupled analysis of the secondary subsystem wherein the response is given in terms of response spectra associated with the attachment points (‘floors’). In order to account for correlations between modal responses and between support motions, an extension of the conventional floor response spectrum, denotedcrossoscillator, cross‐floor response spectrum, is introduced. Important effects of tuning, interaction, non‐classical damping and spatial coupling, which are inherent characteristics of combined primary–secondary systems, are included through the extended spectra. An efficient method for generation of the extended spectra directly in terms of a ground response spectrum is developed.Numerical comparisons with exact results are used to examine the accuracy of the proposed method and to demonstrate the importance of the characteristics mentioned above. In all cases examined, the proposed method shows excellent agreement with exact results. By accounting for the effect of interaction, the proposed method leads to more realistic and economical design criteria for secondary s

ISSN:0098-8847    

DOI:10.1002/eqe.4290140206

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThis study not only attempts to justify an equivalent stationary motion model, but also endeavours to illustrate its potentials as an attractive analysis tool. Using 38 ground accelerations recorded on rock sites as data base, this study first demonstrates that the equivalent stationary motions do give average response spectra compatible with real records. This study also shows that through the equivalent stationary model, a set of motions may be defined by specifying the joint distributions of the model parameters. Finally, by converting a relationship between earthquake magnitude and liquefaction potentials of ground motions, this study has derived normalized magnitude‐dependent response spectra for rock site

ISSN:0098-8847    

DOI:10.1002/eqe.4290140207

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe earthquake response of Pine Flat Dam is examined by a study of time history responses computed for a large set of earthquake ground acceleration records whose time axes have been systematically varied. Linear elastic behaviour is assumed. Topics considered include an investigation of the importance of the presence of water, water compressibility and the vertical component of ground motion; an evaluation of the accuracy of the lumped, added mass representation of the water; and a determination of the intensity of earthquake required to initiate non‐linear behaviour in both the dam and wate

ISSN:0098-8847    

DOI:10.1002/eqe.4290140208

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe dynamic response of unreinforced concrete structures is studied taking account of initiation, extension, closing and reopening of so‐called discrete cracks. The computational procedure is based on the finite‐element method and is at present restricted to two‐dimensional situations. The discrete cracks are simulated by separation of originally adjacent finite elements. An equivalent tensile‐strength criterion is used for the initiation and extension of the cracks which are assumed to propagate perpendicularly to the principal tensile stress. If this direction does not coincide with the interelement boundaries of the finite‐element mesh, the latter is automatically altered. Between elements being separated by a crack special ‘crack elements’ are introduced, which take account of the stress transfer by aggregate interlock. The equations of motion are integrated numerically using an explicit formulation. The procedures outlined are demonstrated on a simplified cross‐section of a concrete gravity dam subjected to horizontal earthq

ISSN:0098-8847    

DOI:10.1002/eqe.4290140209

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290140210

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290140211

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY