摘要:

AbstractSpecially designed arrays of strong motion seismographs located near earthquake sources are required for engineering studies of the near‐source properties and the spatial variation of seismic waves. The SMART‐1 array in Taiwan provides good records for this type of study. Careful study of the observed strong motion data permits the identification of wave types, directions and apparent wave velocities. In this paper, a principal direction ratioR(f,α) is defined; this indicates the principal direction of the motion (along a nearly straight line) within the range 0

ISSN:0098-8847    

DOI:10.1002/eqe.4290130502

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA method for analyzing the earthquake response of elastic, cylindrical liquid storage tanks under vertical excitations is presented. The method is based on superposition of the free axisymmetrical vibrational modes obtained numerically by the finite element method. The validity of these modes has been checked analytically and the formulation of the load vector has been confirmed by a static analysis. Two forms of ground excitations have been used: step functions and recorded seismic components. The radial and axial displacements are computed and the corresponding stresses are presented. Both fixed and partly fixed tanks are considered to evaluate the effect of base fixation on tank behaviour. Finally, tank response under the simultaneous action of both vertical and lateral excitations is calculated to evaluate the relative importance of the vertical component of ground acceleration on the overall seismic behaviour of liquid storage tanks.

ISSN:0098-8847    

DOI:10.1002/eqe.4290130503

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe effect of the base mat flexibility on seismic soil‐structure interaction is studied for an axisymmetric reactor building on a soft and a stiff soil. As a preliminary step, the dynamic response of a massless flexible circular plate with two rigid concentric walls, through which the plate is loaded, is analysed.The response of the plate is found to depend on the plate flexibility, the load distribution and the frequency of excitation. For practical, in‐phase load distributions, the response of the flexible plate is close to that of a rigid plate at low frequencies, but deviates at high frequencies.Including the flexibility of the mat has hardly any effect on the frequencies and damping of the fundamental rocking and vertical modes of the reactor building. This is the case for soft and stiff soil conditions. However, the flexibility of the mat strongly affects the first and higher structural deformation modes. In both cases the amount of energy dissipated in the soil is a significant percentage of the total dissipation, and is essentially unaffected by the mat flexibil

ISSN:0098-8847    

DOI:10.1002/eqe.4290130504

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA simplified analysis procedure for the non‐linear hysteretic earthquake‐response of earth dams is presented. The dam is modelled as a one‐dimensional hysteretic shear‐wedge subjected to base excitation. The hysteretic stress‐strain behaviour of the dam materials is modelled by using elasto‐plastic constitutive equations based on multi‐surface kinematic plasticity theory. The method is based on a Galerkin formulation of the equations of motion in which the solution is expanded using eigenmodes of the linearized problem defined over the spatial domain occupied by the dam. The technique is applied to analyse the non‐linear dynamic response of an earth dam subject to two very different input ground motions. The following investigations are presented: (i) comparison between the results obtained using two soil models depicting different nonlinear properties, (ii) comparison between the results of the one‐mode and the multi‐mode solution expansions, (iii) comparison with the results obtained through an elaborate finite element representation of the dam, and finally, (iv) comparison with the results obtained through the Makdisi‐Seed11iterative procedure for earth dam analysis. The comparisons show that the proposed technique can be used to determine adequately the transient earthquake response of long earth dams. Furthermore, the efficiency and low computational cost make the technique very attractive; it can easily and systematically be extended to two‐ and three‐dimensional calculati

ISSN:0098-8847    

DOI:10.1002/eqe.4290130505

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThis paper evaluates a class of practical optimization techniques for parameter identification of realistic structural dynamic systems. The techniques involve quasi‐Newton methods together with an efficient procedure for estimating complicated error functions. The optimization procedures are verified through their application to several representative examples, including finite‐element models of realistic structural systems. Extensive numerical and graphical results demonstrate the effects of various optimization algorithm parameters on the rate of convergence of the objective function, the parameter vector error norm and the gradient norm. Guidelines are presented as an aid for addressing several significant issues in the practical application of structural dynamics optimization procedures, such as sensitivity problems, uniqueness, initial value definition for the parameter vector, convergence rates, constraints, the effect of alternative cost function definitions, accuracy of alternative gradient evaluation procedures, alternative procedures for estimating the inverse of the Hessian matrix and the use of a quadratic approximation of the objective funct

ISSN:0098-8847    

DOI:10.1002/eqe.4290130506

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractExact stiffness and consistent mass matrices for beams on elastic foundations are derived. Using these matrices it is possible to find the natural frequencies and mode shapes of vibrations, for beams fully or partially supported on elastic foundations. Several examples are given for frequencies and mode shapes of beams partially supported on elastic foundations.

ISSN:0098-8847    

DOI:10.1002/eqe.4290130507

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA method is presented for generating floor response spectra for aseismic design of equipment attached to primary structures. The method accurately accounts fortuning, interactionandnon‐classical damping, which are inherent characteristics of composite oscillator‐structure systems. Modal synthesis and perturbation techniques are used to derive the modal properties of the composite system in terms of the known properties of the structure and the oscillator. Floor spectra are generated directly in terms of these derived properties and the input ground response spectrum using modal combination rules that account for modal correlations and non‐classical damping. The computed spectra, in general, are considerably lower than conventional floor response spectra due to the effect of interaction. They provide more realistic and economical criteria for design of equipment. The method is accurate to the order of perturbation and is computationally efficient, as it avoids time‐history analysis and does not require numerical eigenvalue evaluation of the composite oscillator‐structure system. The results of a parametric study demonstrate the accuracy of the method and illustrate several key features of floor respons

ISSN:0098-8847    

DOI:10.1002/eqe.4290130508

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290130509

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290130510

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290130511

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY