ISSN:0098-8847    

DOI:10.1002/eqe.4290060102

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractA study is made of the harmonic response of a rigid massless rectangular foundation bonded to an elastic half‐space and subjected to the action of both external forces and obliquely incident plane seismic waves. The associated mixed boundary value problem is discretized and solved numerically. The results obtained indicate that the angle of incidence of the seismic wave has a marked effect on the nature and magnitude of the foundation respons

ISSN:0098-8847    

DOI:10.1002/eqe.4290060103

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractAn analysis is made of the steady‐state response of a bilinear hysteretic structure supported on the surface of a viscoelastic half‐space. The method of equivalent linearization is used to solve the equations of motion, and simplified approximate formulas are obtained for the fundamental resonant frequency of the system and for an effective critical damping ratio. Numerical results indicate that for non‐linear hysteretic structures compliance of the soil foundation may lead to larger displacements than would occur if the base were rigid. This behaviour differs from that generally observed for linear systems, for which the effect of soil‐structure interaction is to reduce the rigid‐base

ISSN:0098-8847    

DOI:10.1002/eqe.4290060104

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractNear‐fault records of the 1971 San Fernando earthquake contain severe, long duration acceleration pulses which result in unusually large ground velocity increments. A review of these records along with the results of available theoretical studies of near‐fault ground motions indicates that such acceleration pulses may be characteristic of near‐fault sites in general.The results of an analytical study of a building severely damaged during the San Fernando earthquake indicate that such severe, long duration acceleration pulses were the cause of the main features of the observed structural damage. The implications of such pulses on current aseismic design methods, particularly those used to establish design earthquakes, are examined for buildings located near potential earthquake faults. Analytical studies of the non‐linear dynamic response of single and multiple degree‐of‐freedom systems to several near‐fault records, as well as to a more standard accelerogram, indicate that at near‐fault sites: (a) very large displacement ductilities may result for current levels of code design forces; (b) smoothed elastic design response spectra should reflect the larger ground velocities that may occur; and (c) peak inelastic response cannot reliably be inferred from elastic respo

ISSN:0098-8847    

DOI:10.1002/eqe.4290060105

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractAn experiment was carried out to develop a technique to measure shear wave velocity simultaneously with the standard penetration test popular in soil engineering. In the standard penetration test an impact at the bottom of a borehole is produced by weight dropping and may be expected to generate seismic waves. A three‐component geophone was set on the ground surface near the borehole and the waves generated were recorded with a magnetic recorder at successive depths of the penetration test. The predominance of the SV wave obtained with this simple method was assured by measurement of the particle orbit. Signal amplitudes decrease with depth and become less than the noise level at a certain depth. Therefore records from deeper sources must be processed to disclose the shear waves. Since waveforms of SV events generated by blows of the penetration test at a given depth are very similar, the signal to noise ratio would be expected to be improved by a stack of wave trains. A paste‐up of the radial component after stacking was compared with that before stacking and a refinement was clearly recognized.A vertical distribution of shear wave velocity was obtained by reading the onset time at each depth. Shear wave velocities thus obtained were compared with N values from the standard penetration test and specific resistivities from electrical logging in the same borehole. The data were mutually consistent.This experiment showed that a convenient, precise shear wave velocity measurement can be conducted during the routine work of a standard penetration t

ISSN:0098-8847    

DOI:10.1002/eqe.4290060106

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractA general substructure method for analysis of response of structures to earthquake ground motion, including the effects of structure‐soil interaction, is presented. The method is applicable to complex structures idealized as finite element systems and the soil region treated as either a continuum, for example as a viscoelastic halfspace, or idealized as a finite element system. The halfspace idealization permits reliable analysis for sites where essentially similar soils extend to large depths and there is no rigid boundary such as soil‐rock interface. For sites where layers of soft soil are underlain by rock at shallow depth, finite element idealization of the soil region is appropriate; in this case, the direct and substructure methods would lead to equivalent results but the latter provides the better alternative. Treating the free field motion directly as the earthquake input in the substructure method eliminates the deconvolution calculations and the related assumption—regarding type and direction of earthquake waves—required in the direct method.Spatial variations in the input motion along the structure‐soil interface of embedded structures or along the base of long surface supported structures are included in the formulation.The substructure method is computationally efficient because the two substructures—the structure and the soil region—are analysed separately; and, more important, it permits taking advantage of the important feature that response to earthquake ground motion is essentially contained in the lower few natural modes of vibration of the structure

ISSN:0098-8847    

DOI:10.1002/eqe.4290060107

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290060108

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThis paper presents an approximate analytical technique for determining the steady‐state response of a class of systems with spatially localized non‐linearity. A method of finding the amplitude peaks in various modes is presented. Numerical examples illustrate the nature and accuracy of the results of the approximate analy

ISSN:0098-8847    

DOI:10.1002/eqe.4290060109

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe dynamic response to ground motion of hemispherical shells in a fluid, medium is studied numerically. In the analysis, linear thin shell theory is used and the fluid is assumed to be compressible and inviscid. The effect of the duration of the ground motion on the dynamic response is studied using two forcing functions, one with a very short duration and the other in the form of a Heaviside function. As special cases, dynamic responses of the shellin vacuoand of a rigid hemisphere in the fluid medium are investigated. The results are valid also for a ring‐stiffened complete spherical shell accelerating in an acoustic mediu

ISSN:0098-8847    

DOI:10.1002/eqe.4290060110

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe concept of collocation, originally used by Wilson in the development of dissipative algorithms for structural dynamics, is systematically generalized and analysed. Optimal schemes within this class are developed and compared with a recently proposed family of dissipative algorithms, called a methods. The α methods are found to be superior on the basis of standard measures of dissipation and dispersion.It is pointed out that the tendency to overshoot is an important and independent factor which should be considered in an evaluation of an implicit scheme. The basis for studying overshoot is discussed and the optimal collocation and α methods are compared. It is found that pathological overshooting is an inherent property of collocation schemes, whereas the overshooting characteristics of the α methods are go

ISSN:0098-8847    

DOI:10.1002/eqe.4290060111

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY