摘要:

AbstractA discrete model to represent the unbounded soil (halfspace) in a soil–structure interaction analysis in the time domain is developed. For each dynamic degree of freedom of the foundation node, the discrete model consists of a massM0which is attached to a rigid support with a springKand with a damper C0. In addition, a free node with the massM1is introduced, which is connected to the foundation node with a damperC1. All coefficients are frequency‐independent. The discrete model is semi‐empirical. It is based on a semi‐infinite truncated cone, whereby, after enforcing the static stiffness, the remaining parameters are modified to achieve an optimal fit of the dynamic‐stiffness coefficient in the frequency domain.The springKis equal to the static stiffness. The coefficients appearing in the equations for the dampersC0,C1and the massesM0,M1are specified (assuming a homogeneous halfspace) for the disc, the embedded cylinder, the rectangle (also embedded) and the strip. A square on a layer whose stiffness increases with depth resting on a homogeneous halfspace is also treated. For an embedded foundation, eccentricities arise. Material damping increases the damperC0and t

ISSN:0098-8847    

DOI:10.1002/eqe.4290140502

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractMode‐superposition analysis is an efficient tool for the evaluation of the response of linear systems subjected to dynamic agencies. Two well‐known mode‐superposition methods are available in the literature, the mode‐displacement method and the mode‐acceleration method. Within this frame a method is proposed called adynamic correction methodwhich evaluates the structural response as the sum of a pseudostatic response, which is the particular solution of the differential equations, and a dynamic correction evaluated using a reduced number of natural modes.The greater accuracy of the proposed method with respect to the other methods is evidenced through extensive numerical tests, for classically and non‐classically dam

ISSN:0098-8847    

DOI:10.1002/eqe.4290140503

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAn index is proposed for the quantitative evaluation of topographical effects, as may be required in seismic microzoning and structural design applications. This topographical effects index (TEI) is defined as the relative Arias intensity for a given position.As an example, the TEI is calculated for a semicircular canyon excited by an earthquake signal that consists of plane elastic SH waves and is characterized by a theoretical spectrum of accelerations. The analytical solution by Trifunac15provides the transfer functions for this problem. The behaviour and spacial distribution of the calculated TEI values are illustrated for different incidence angles and spectral parameters.The proposed index appears useful for generating quantitative criteria which, after proper confirmation by instrumental recordings, could be considered in earthquake code provisions.

ISSN:0098-8847    

DOI:10.1002/eqe.4290140504

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractOnly when the data base is of sufficient quality can a theoretical model of any process be justified. Such a data base has recently been assembled in the field of damping in tall buildings. It is now possible to specify a damping value appropriate to a particular building vibrating at a specified amplitude which is well correlated with values which are measured in practice. The mechanism on which this predictor is based suggests that the predictor will be applicable to other types of structure as well. As yet the data base for these other structures does not exist, but some circumstantial evidence is encouraging.

ISSN:0098-8847    

DOI:10.1002/eqe.4290140505

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractUnder the assumption of an immovable point source for the earthquake energy release, a mathematical model is developed to compute the components of the free field surface rotation consistent with assigned translational components.Experimental evidence on these quantities is offered by the strong‐motion instrument arrays. However, lack of adequate identification of the different wave contributions prevents in general a direct measurement of rotational and torsional components, allowing only a qualitative assessment of just how large these components might be. The only exceptions are the records of SMART‐1, which offer the entire information to derive rotations.The available data of strong‐motion instrument arrays for this problem are summarized in Table I. They are in qualitative agreement with the suggestions of the mathematical model.Earthquake response spectra for the rotational components are developed for a few selected cases, in particular a rotational spectrum consistent with the prescription ofUSNRC Regulatory Guide1.60.The correlations between the translational and rotational components of the ground motion are also

ISSN:0098-8847    

DOI:10.1002/eqe.4290140506

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe linear response of a selected arch dam to harmonic upstream, cross‐stream or vertical ground motion is presented for a wide range of the important system parameters characterizing the properties of the dam, impounded water, reservoir boundary materials and foundation rock. Based on these frequency response functions, the hydrodynamic and foundation flexibility effects in the dynamic response of arch dams are investigate

ISSN:0098-8847    

DOI:10.1002/eqe.4290140507

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe necessary and sufficient conditions for global optimality and the closed form solution are derived for a problem of minimizing a weighted sum of storey stiffnesses of a shear building subject to a fundamental frequency constraint. A set of higher frequency formulae is derived for optimally designed shear buildings with equal masses. It is shown that, if the weight coefficients are regarded as parameters for adjustment, the distribution of the SRSS estimates of the maximum interstorey drifts can be adjusted so as to coincide with a specified one. The base shear–fundamental period formulae and the base shear–design drift formulae are derived semi‐analytically for shear buildings with equal masses on the basis of the optimum design formulae and the SRSS estimates of the maximum interstorey drifts. Some numerical examples are presented in order to illustrate the validity of the proposed method of earthquake‐response constrained

ISSN:0098-8847    

DOI:10.1002/eqe.4290140508

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290140510

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290140512

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290140513

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY