摘要:

AbstractThe convergence and energy‐dissipation characteristics of an unconditionally stable implicit time integration scheme that has been adopted for pseudodynamic testing are examined in this paper. A convergence criterion is derived for general multiple‐degree‐of‐freedom softening systems. Furthermore, it is shown that undesired loading and unloading cycles can be avoided in numerical iterations by scaling down the incremental corrections. Finally, it is proved that the total energy dissipation introduced by the residual convergence errors and proposed numerical correction is always positive for any softening str

ISSN:0098-8847    

DOI:10.1002/eqe.4290200902

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe ground motions produced by an earthquake at the multiple support points of large structures can differ considerably. In this study, the quasi‐static, the dynamic and the total structural responses of a multiply supported rigid plate to spatially varying multiple ground motion inputs are analysed. The results, together with those obtained by neglecting ground motion phase shifts and those by neglecting ground motion coherency losses, are compared with the corresponding structural responses to a single input. The comparisons show that the single input method overestimates translational responses and underestimates rotational responses. They also show that the responses are sometimes overestimated and sometimes underestimated by neglecting the coherency loss effects between the multiple ground motion excitation

ISSN:0098-8847    

DOI:10.1002/eqe.4290200903

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe safety of structures built in seismic regions can be improved by energy absorbing devices. Passive isolation systems such as base isolators are suitable for low‐rise structures, but they provide only a partial solution to the problem. Three active control techniques for reducing the dynamic response of machine supporting foundations using various control strategies are presented. The active tendon, active mass damper and active base control systems are studied for active control of machine foundations in seismic regions. Numerical simulations show that active control can reduce the dynamic response of turbomachine foundations under seismic loads. This reduction in dynamic response can limit damage to power plants during earthquakes and restore their operation in a short tim

ISSN:0098-8847    

DOI:10.1002/eqe.4290200904

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe transient response of a concrete gravity dam to a selected earthquake record is determined in order to evaluate the significance of the sedimentary material accumulating on the bottom of the reservoir. The sediment is modelled as a two‐phase medium (fluid‐filled, poroelastic solid), and the analysis is carried out accounting for all interactions between system components (dam, water, sediment, foundati

ISSN:0098-8847    

DOI:10.1002/eqe.4290200905

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThree‐dimensional scattering of seismic waves by a cylindrical alluvial valley embedded in a layered half‐space is investigated by using the combination of the boundary integral representation and the finite element method. The surface displacements due to incident plane harmonic body waves (P, SV and SH) propagating at an arbitrary angle to the axis of the cylindrical valley are evaluated numerically for two semi‐elliptical alluvial valleys. The presence of the layer is found to have a strong effect on the amplification of the surface displacements in some cases. The three‐dimensional motion seems to be quite critical and may cause large amplification. The surface ground motion becomes significant when compared with corresponding free‐field motion as the wavelengths become comparable to the characteristic length of the valley. The maximum amplification always occurs atop the valley. Numerical results show that the amplitude and the amplification pattern of the surface displacement strongly depend upon the frequency, the angle and the type of the incid

ISSN:0098-8847    

DOI:10.1002/eqe.4290200906

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA simple local error estimator is presented for time integration schemes in dynamic analysis. This error estimator involves only a small computational cost. The time step size is adaptively adjusted so that the local error at each time step is within a prescribed accuracy. It is found that the estimator performs well under various circumstances and provides an economical adaptive process. Attempts to estimate the global time integration error are also reported.

ISSN:0098-8847    

DOI:10.1002/eqe.4290200907

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290200908

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290200909

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290200901

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY