摘要:

AbstractBased on cyclic load tests of large‐scale reinforced concrete elements and assemblages, a probabilistic model of member failure is developed. The model gives the probability of survival at timetas a functional of damage ratio and dissipated energy up tot. After extension to multivariate survival of several members with correlated resistance, the model is used to calculate the safety of reinforced concrete frames subjected to given input motions. Results are in terms of the probability of local failure and of no failure anywhere in the syste

ISSN:0098-8847    

DOI:10.1002/eqe.4290100202

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe effect of placing barriers in the travel path of P, SV and SH seismic waves has been studied using time‐domain solutions of plane‐strain finite element programs for two‐dimensional crustal models. The wavefields considered propagate parallel to the free surface of an elastic medium consisting of a single layer over a halfspace. Barriers take the form of open‐air trenches. Effects of damping are assessed by considering representative viscoelastic conditions. Computations are presented as the ratio of spectral energy observed at a point with the barrier system in place in the model to the spectral energy observed at the same point without the barrier system in the model. These spectral ratios are dependent upon the direction of wave propagation.The calculations brought to light the marked role of surficial layering and attenuation properties of the surface rocks or soils on the effectiveness of seismic trench barriers. Barrier models without these features cannot in general reliably predict seismic wavefields at the surface. In the range of cases studied, trench depthdrather than width is the most sensitive parameter. When the ratiod/λ, the ratio of trench depth to the wavelength of shear waves, is greater than about 0·6, power spectral ratios of 0·06 and less are found for SH waves and the vertical component of SV motion for frequencies of 4–6 Hz. By contrast, for frequencies less than 3–4 Hz, power spectral ratios from unity to about two and greater are observed, indicating amplification for the horizontal component of wave motion. Spectral ratios calculated at some locations in front of the barrier system show over two‐fold amplification. Spectral ratios also change significantly with the relative location of the free surface o

ISSN:0098-8847    

DOI:10.1002/eqe.4290100203

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractUsing a 40‐storey building as an example, the structural response under the excitation of horizontal earthquake ground motion is shown to vary greatly with the direction from the building site to the epicentre. Two mathematical models are used to represent the ground motion: the stationary random process model and the evolutionary‐type non‐stationary random process model. The former model is suitable if the duration of the most intense portion of an earthquake is much longer than the fundamental natural period of the structure. The maximum standard deviations of selected structural response quantities are computed and plotted for all possible epicentre directions, and the information is believed to be useful for design pur

ISSN:0098-8847    

DOI:10.1002/eqe.4290100204

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA reactor building founded on a large number of piles situated in a layered site is analysed for an historic earthquake assumed to be propagating horizontally. Pile‐soil‐pile interaction is properly accounted for, incorporating the frequency‐dependent stiffness and radiation damping. Compared to vertical incidence, the pile forces are increased and the piles close to the boundary are loaded more heavily than those in the centre region of the ba

ISSN:0098-8847    

DOI:10.1002/eqe.4290100205

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractBased on an incremental Hamilton's principle a versatile and systematic computer method for analysing non‐linear structural vibrations is developed in this paper. The essence of the proposed method can be regarded as an incremental harmonic balance method associated with a finite strip procedure in the time‐space domain. Only linearized equations in terms of frequency increment, amplitude increments, etc. have to be formulated and solved in each incremental step. This method is applicable to highly non‐linear problems and may be generalized to related non‐linear periodic structural motions such as dynamic stability, flutter and some motions of a rotating body, etc. To show the effectiveness and versatility of this method, a typical time‐space finite strip for beam problems is worked out and examples for a wide variety of vibration problems including free and forced vibrations, super‐ and sub‐harmonic resonances, and complicated phenomena such as internal resonance are computed. Comparisons with previous results

ISSN:0098-8847    

DOI:10.1002/eqe.4290100206

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractAnalytical results are presented for the dynamic interaction of an elastic flexural plate and an elastic half‐space subjected to harmonic seismic waves. Displacements and contact stresses are presented for square, massless plates having a practical range of flexural stiffness and subjected to incident waves oriented parallel to either an edge or a diagonal of the plate. The behaviour of massive plates is also briefly discussed; such plates exhibit additional resonances higher than those normally associated with the motion of a rigid mas

ISSN:0098-8847    

DOI:10.1002/eqe.4290100207

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractAn experimental study of non‐linear mechanisms that may occur during intense seismic response of arch dams is described in this paper. The presentation deals with three types of non‐linearity that were observed during shaking table model studies: monolith joint opening, cantilever cracking, and reservoir cavitation at the dam face.The monolith joint opening phenomenon was represented by a segmental arch ring model that simulated a horizontal slice of a prototype dam. The cantilever cracking and reservoir cavitation mechanisms were studied using a model gravity dam section. The principal conclusion of the investigation was that shaking table experiments provide a practical means of studying the non‐linear earthquake response of concrete arch dams, including their actual failure mecha

ISSN:0098-8847    

DOI:10.1002/eqe.4290100208

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe apparent horizontal propagation velocity, that is the propagation velocity of seismic waves with respect to the ground surface, is discussed in this paper. This parameter is needed to determine the effects of earthquakes on long structures such as bridges and buried pipelines as well as the torsional rotation of foundations of multi‐storey buildings. A time window intensity tensor introduced by Penzien and Kubo is used herein to determine the predominant directions of ground motion during an earthquake. Considering the reflection of waves at a free surface, an approximate relationship between the predominant direction and the angle of incidence of body waves with respect to the ground surface is presented. Knowing the material properties of the top layer and the angle of incidence, the desired propagation velocity with respect to the ground surface is readily calculated.The median value of the apparent propagation velocity of shear waves for near field sites which recorded the 1971 San Fernando earthquake was determined to be about 2‐1 km/s using the above method. A similar value for the 1979 Imperial Valley earthquake is 3·7 km/s. These values are consistent with the range of values for the apparent propagation velocity determined by other researc

ISSN:0098-8847    

DOI:10.1002/eqe.4290100209

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractMode superposition has become a standard tool in the treatment of seismic analysis. Its advantages are appealing to the analyst. After years of widespread use of the method, it could be said that it is well understood, both in theory and application. However, its routine application can lead to errors caused by the analyst neglecting truly representative modes in the system response.In this paper, a very simple technique is suggested for representing, under certain conditions, the effect of the higher modes: the residual mode method. The effectiveness of the method in the context of response spectrum analysis is discussed, and such analysis is illustrated by a numerical example.

ISSN:0098-8847    

DOI:10.1002/eqe.4290100210

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractAn analysis procedure in the frequency domain is developed for determining the earthquake response of two‐dimensional concrete gravity and embankment dams including hydrodynamic effects; responses of the elastic dams and compressible water are assumed linear. The dam and fluid domain are treated as substructures and modelled with finite elements. The only geometric restriction is that an infinite fluid domain must maintain a constant depth beyond some point in the upstream direction. For such an infinite uniform region, a finite element discretization over the depth is combined with a continuum representation in the upstream direction. The fluid domain model approximately accounts for interaction between the fluid and underlying foundation medium through a damping boundary condition applied along the reservoir bottom, while the dam foundation is assumed rigid. Several examples are presented to demonstrate the accuracy of the fluid domain model and to illustrate dam responses obtained from the analysis procedur

ISSN:0098-8847    

DOI:10.1002/eqe.4290100211

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY