摘要:

AbstractThe cyclic shear stress‐deformation response of dry sand‐concrete interfaces is described using a modified form of a Ramberg–Osgood (R‐O) model. The model permits the description of the interface secant stiffness as a function of the normal stress, shear stress, sand density and number of loading cycles. Stiffening behaviour, or an increase in secant shear stiffness with number of cycles, may be represented, as well as degradation behaviour.Typical results from a series of cyclic direct shear tests are presented. A methodology is described by which the parameters for the (R‐O) model can be determined from the laboratory shear tests, and the functional forms of the parameters for the sand‐concrete interface are provided.The model is verified by predicting the response of two displacement controlled laboratory tests that were used for the determination of the model parameters. An additional verification is presented in which the response is predicted for a test not used in the parameter determination. The model is shown to simulate satisfactorily the cyclic response, including the effect of number of loa

ISSN:0098-8847    

DOI:10.1002/eqe.4290140102

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA rigorous analytical solution is developed for the lateral linear shear response of embankment dams in semi‐cylindrical valleys. Closed‐form algebraic expressions are presented pertaining to both free and base‐induced oscillations, and extensive parametric and comparative studies elucidate the prominent effects of canyon geometry (shape and aspect ratio) on dynamic response. Harmonic steady‐state as well as earthquake‐induced accelerations, displacements and shear strains in the dam are studied and compared with those obtained from 3‐Dimensional analyses for other canyon geometries, as well as from 2‐Dimensional (2‐D) analyses of the dam mid‐section. It is shown that such 2‐D analyses may provide significantly lower values of near‐crest accelerations, but slightly higher values of shear strains and stresses than the 3‐D analyses. The proposed method of analysis is at least three orders of magnitude less expensive than other presently availab

ISSN:0098-8847    

DOI:10.1002/eqe.4290140103

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA method for the dynamic finite element analysis of a non‐axisymmetric soil model with an axisymmetric boundary is presented. In the non‐axisymmetric soil domain an arbitrary discretization with three‐dimensional isoparametric solid elements is used. At the boundary a transmitting element is arranged. It is based on the semi‐analytical element of Waas and Kausel. The transformation of the stiffness matrix of the Waas/Kausel element with cyclic symmetric displacements to general displacement fields is presented. For earthquake excitation the forces acting on the discretized domain are given. The method is illustrated by the dynamic analysis of an embedded box‐type building. The distribution and magnitude of significant section forces are

ISSN:0098-8847    

DOI:10.1002/eqe.4290140104

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA method is developed applicable to problems of dynamics of arbitrary‐geometry foundations. Finite elements are employed in the near field in order to obtain a discrete solution. In the far field, a semidiscrete solution is synthesized from modes also calculated by the finite element method. The solutions are matched by applying the stationarity condition of a functional. Examples of application are presented in order to verify the validity and illustrate the use of the metho

ISSN:0098-8847    

DOI:10.1002/eqe.4290140105

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe problem of determining the limiting performance of vibrating systems under shock loading is solved by replacing portions of the system by control forces which can represent any design. For the class of problems treated here, the performance index and the constraints are linear combinations of system response variables such as displacements, velocities and accelerations. Furthermore, the equations of motion are linear, so that it is possible to formulate the optimization procedure as a linear programming problem. In expressing the performance index and the constraints as linear functions of the unknown control forces, a modal approach is used to simplify and improve previous treatments of this problem. In spite of these linearity requirements, the control forces are not required to be linear functions of the response variables.

ISSN:0098-8847    

DOI:10.1002/eqe.4290140106

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe various boundary‐element methods, well established in the frequency domain, are developed in the time domain for a foundation embedded in a layered halfspace. They are the weighted‐residual technique and the indirect boundary‐element method, based on a weighted‐residual equation, and the direct boundary‐element method based on a reciprocity equation, both equations involving time and space. In the indirect approach, formulating the weighted‐residual equation over the last time step only results in the truncated indirect boundary‐element formulation which requires a reduced computational effort. In all cases, convolution integrals occur.The truncated indirect boundary‐element method leads to a highly reliable algorithm, as is verified when a linear analysis in the time domain is compared to the corresponding one in the frequency domain. This boundary‐element formulation, which is non‐local in space and time, represents a rigorous generally applicable method taking into account a layered halfspace in a non‐linear soil‐structure interaction analysis.As an example, the non‐linear soil‐structure interaction analysis of a structure embedded in a halfspace with partial uplift of the basemat and separation of th

ISSN:0098-8847    

DOI:10.1002/eqe.4290140107

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe paper examines the effect on the structural response of the inevitable correlation which exists between the six earthquake components acting along a set of structural axes. The rotational components are expressed in terms of the spatial derivatives of the translational components. For the calculation of response, modal analysis is employed so that ground response spectra can also be used as seismic input. A methodology is developed to obtain the maximum mean square response which can occur in a structure, irrespective of its orientation with respect to the impinging seismic waves. The application of this methodology for the calculation of design response is advocated, especially for asymmetric structures. For the assumed model of seismic wave motion, the numerical results show a significant contribution to the response from the rotational components. This contribution is, however, expected to be reduced by structural foundation averaging and interaction effects. Further studies with more complete models of seismic wave motions, and their interaction with structural foundations, are thus warranted for a realistic evaluation and characterization of the rotational inputs for design purposes.

ISSN:0098-8847    

DOI:10.1002/eqe.4290140108

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe transient extensional vibrations of a slender and uniform bar, which is clamped at one end and is subjected to an axial force at the other free end, are investigated by applying three methods: the Laplace transform method, the normal mode and Newmark β methods in conjunction with the finite element method (FEM); the errors caused by the spatial discretization of the FEM and the direct integration of the Newmark β method are studied and compared with those of the previous paper where the flexural vibrations of a cantilever beam were considered. The reason why the extensional vibration problem is investigated here is that the condition seems to be severe due to the closeness of adjacent natural frequencies, the larger values of natural frequencies and the smaller number of nodal variables of the FEM in comparison with those of the flexural vibration problem. The numerical results show that the errors in response of the extensional vibration problem are large. However, if one follows the criterion proposed in this paper, accurate response is obtainable by the Newmark β method, which requires less computer time than either of the other methods mentioned abo

ISSN:0098-8847    

DOI:10.1002/eqe.4290140109

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe step‐by‐step modal time history integration methods are developed for dynamic analysis of non‐classically damped linear structures subjected to earthquake‐induced ground motions. Both the mode displacement and mode acceleration‐based algorithms are presented for the calculation of member and acceleration responses. The complex‐valued eigenvectors are used to effect the modal decoupling of the equations of motion. However, the recursive step‐by‐step algorithms are still in terms of real quantities. The numerical results for the acceleration response and floor response spectra, obtained with these approaches, are presented. The mode acceleration approach is observed to be decidedly better than the mode displacement approach in as much as it alleviates the so‐called missing mass effect, caused by the truncation of modes, very effectively. The utilization of the mode acceleration‐based algorithms is, thus, recommended in all dynamic analyses for earthquake‐i

ISSN:0098-8847    

DOI:10.1002/eqe.4290140110

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290140111

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY