摘要:

AbstractThe analysis of dynamic soil‐bridge interaction has been performed in three steps. These are:1.The analysis of input motions.2.The force‐displacement relationships for the foundations.3.The dynamic analysis of the structure itself, i.e. the bridge.Based on the exact solution of the first two steps, the dynamic interaction of a simple two‐dimensional bridge model erected on an elastic half‐space has been investigated for a single span case. The two‐dimensional model under study consists of an elastic shear girder bridge supported by two rigid abutments and rigid foundations which have a circular cross‐section and are welded to the half‐space. It has been shown that the dynamic interaction depends on:1.The incidence angle of plane SH‐waves.2.The ratio of the rigidity of the girder and the soil.3.The ratio of the girder mass to the mass of the rigid abutment‐foundation system.4.The span of the bridge.The dynamic response of the girder and the effect of the radiative damping in the half‐space on the interaction of the girde

ISSN:0098-8847    

DOI:10.1002/eqe.4290050202

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe problem of vibrations at the free surface of an elastic half‐space due to detonation of a buried source is studied here from the viewpoint of the geophysical seismic technique employed in oil exploration. The fundamental assumption of the theory, therefore, is that the pressure at the source is impulsive and a Dirac delta function of time. The depth of the source below the surface of the medium is considered in the present theory as an additional parameter which has hitherto made the buried source problem formidable and, therefore, has limited almost all previous works to the relatively easy problem of surface blasting.An exact formulation is presented by dividing the half‐space into a stratum above the level of the buried source and a half‐space below it. For boundary conditions at the interface, it is assumed that the vertical displacement and shear stress at the level of the source are continuous while the direct stress is discontinuous. A numerical evaluation of the contour integration in the analysis is presented for the components of vibrations at any point of the free surface for a Poissonian medium. Finally, the analysis provides a theoretical justification for the interesting results obtained from field experiments recorded in an earlier

ISSN:0098-8847    

DOI:10.1002/eqe.4290050203

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe largest British earthquake to occur in several hundred years took place in Essex, in the south east of England, in 1884. From contemporary accounts and a recent visit to the area affected by the earthquake, the intensity of the earthquake was assessed. It is estimated that the peak accelerations generated may have been as much as 0.1 g. This would be of consequence to some modern structures, designed without earthquake provisions.

ISSN:0098-8847    

DOI:10.1002/eqe.4290050204

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290050205

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractShear wave velocities of soils, which provide shear moduli for earthquake response calculations, can be measured clearly and accurately using the down‐hole method. Such a method has been used at a number of sites in California with good results to depths of 200 ft. Seismic waves from hammer blows, delivered to the ends of a heavy plank loaded by the front wheels of a vehicle, are received by a three‐component geophone in a carefully prepared vertical hole and recorded at 1 mm/ms with a six‐channel seismograph. A series of records are obtained at various measured depths in the hole, allowing calculation of interval velocities. Shear waves are easily identified by a clear 180 degrees phase difference between waves generated by blows on the opposite ends of the plank. Compressional waves are routinely logged by a vertical hammer blow at each recording depth. Shear velocities are reproducible to about 5 per cent in surveys of neighbouring holes. The reading uncertainty of ± 1 msec for the S arrival gives a resolution sufficient to detect a buried layer 5–10 ft thick with a velocity contrast of only 20

ISSN:0098-8847    

DOI:10.1002/eqe.4290050206

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe finite strip procedure is used to predict the free vibration response of both planar and non‐planar coupled shear wall assemblies. The solid walls are considered as vertical cantilever strips and a comparison is made between modelling the spandrel beams as discrete beams and as an equivalent continuum with orthotropic plate properties. It is shown that both approaches lead to essentially the same frequencies. The effects of vertical inertial forces and shear deflection are included, and structures considered may have properties that vary with height. The method presented appears to be more versatile than previously published techniques and numerical comparisons with existing methods indicate the predicted results to be accurat

ISSN:0098-8847    

DOI:10.1002/eqe.4290050207

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290050208

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290050209

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290050201

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY