摘要:

AbstractThe calculation of design spectra for building sites threatened by seismic ground motion is approached by considering the maximum responses of linearly elastic oscillators as indicators of ground motion intensity. Attenuation functions describing the distribution of response as a function of earthquake magnitude and distance are derived using 68 components of recorded ground motion as data. With a seismic hazard analysis for several hypothetical building sites, the distributions of maximum oscillator responses to earthquakes of random magnitude and location are calculated, and spectra are drawn to indicate the maximum responses associated with specified probability levels. These spectra are compared to design spectra calculated from published methods of amplifying peak ground motion parameters. The latter spectra are found to be inconsistent in terms of risk for building sites very close and very far from faults. A ground motion parameter defined to be proportional to the maximum response of a 1 Hz, 2 per cent damped linearly elastic oscillator is investigated; this parameter, in conjunction with peak ground acceleration, is found to lead to risk‐consistent design spectra. Through these two parameters, a design earthquake magnitude and design hypocentral distance are defined, for a specified building site and risk level. The use of these parameters in the seismic hazard mapping of a region is illustrate

ISSN:0098-8847    

DOI:10.1002/eqe.4290050302

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractApproximate solutions to the forced vibrations of a rigid circular plate attached to the surface of an elastic halfspace are presented for large values of the frequency factor. These results are important when solving soil‐structure interaction problems when such problems involve high‐frequency factors. This situation arises when high‐frequency components of earthquakes are associated with a relatively rigid foundation of a large base area and located on a soft terrain. Similar situations occur in cases of blast loadings and impact and in the foundations of large high‐speed machinery. These solutions are used to solve the problem of the motion of a rigid mass on an elastic halfspace subjected to steady state and transient horizontal accelerations. From these results, it is deduced that a large rigid mat foundation located on soft terrain significantly attenuates input accelerations and consequently may be useful as the foundation of large massive rigid structures such as a nuclear power

ISSN:0098-8847    

DOI:10.1002/eqe.4290050303

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe resistance of a soil layer to steady horizontal vibration of an elastic pile is theoretically investigated. The pile is assumed to be vertical and of circular cross‐section. The soil is modelled as a linear viscoelastic layer with hysteretic material damping. A closed form solution is obtained for the resistance of the soil layer to the motion. This resistance depends on shear modulus of soil, frequency, pile slenderness, material damping and Poisson's ratio. A parametric study of the effect of these parameters is included. The soil layer resistance is expressed in a form which can be used directly in the solution of the soil‐pile interaction problem which is treated in a subsequent paper. The approach also applies for rigid deeply embedded footi

ISSN:0098-8847    

DOI:10.1002/eqe.4290050304

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractInteraction between soil and an elastic pile vibrating horizontally is theoretically examined. The soil is modelled as a linear, viscoelastic layer overlying rigid bedrock. The pile is assumed to be vertical and point bearing. This study utilizes the definition of soil resistance presented in a preceding paper.1A direct solution is developed which yields closed form formulas for pile displacement, stiffness and damping. A parametric study clarifies the role of the parameters involved, illustrates the interaction between the soil and the pile and shows the stiffness and damping properties of the soil‐pile system for typical values of the governing parameter

ISSN:0098-8847    

DOI:10.1002/eqe.4290050305

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractA new family of unconditionally stable one‐step methods for the direct integration of the equations of structural dynamics is introduced and is shown to possess improved algorithmic damping properties which can be continuously controlled. The new methods are compared with members of the Newmark family, and the Houbolt and Wilson method

ISSN:0098-8847    

DOI:10.1002/eqe.4290050306

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractTwo efficient schemes have been developed for the analysis of discrete systems of sites. Both schemes have the same objective of finding the probability of simultaneous failure of any number of sites belonging to a given system of sites subject to threats from a given set of earthquake sources with known seismic history. In the first scheme, systems with deterministic site resistances can effectively be analysed using a non‐linear transformation of variables. In the second scheme, systems with random site resistances can be analysed. To overcome the computational difficulties involved in the analysis, a new set of simple recursive formulas has been developed and used effectively. Based on these two schemes, two efficient computer programs were prepared and used to perform a parametric study on a system of nine actual or contemplated nuclear power plants in New England. The results have shown that the problem is very sensitive to the coefficient of variation of the resistances and not so sensitive to the mean resistance

ISSN:0098-8847    

DOI:10.1002/eqe.4290050307

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractSome results of approximate analyses of the safety of earthquake protection systems with reserve elements are presented. Systems with one and several reserve elements are considered. The overshoot random vibration approximation is used for analysis. A numerical example is given. It is shown that the failure probability of structures with reserve elements is considerably lower and the safety is much higher when compared with similar characteristics of structures without reserve elements.

ISSN:0098-8847    

DOI:10.1002/eqe.4290050308

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290050309

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290050301

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY