摘要:

AbstractIn pseudodynamic tests, experimental feedback errors are accumulated in the step‐by‐step integration procedure. In this paper, the growth of cumulative experimental errors is examined. Approximate cumulative error bounds are derived for linear single‐ and multi‐degree‐of‐freedom systems, based on realistic models of random and systematic feedback errors. These studies show that the rate of cumulative error growth with respect to the integration time step increases rapidly with the natural frequency of the specimen and the integration time interval used. Hence, the higher modes of a multi‐degree‐of‐freedom system are more sensitive to experimental errors than the lower ones. Furthermore, it is shown that some systematic errors are extremely undesirable. Rational criteria for assessing the reliability of pseudodynamic test resu

ISSN:0098-8847    

DOI:10.1002/eqe.4290150402

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractIn a pseudodynamic test, errors in restoring‐force feedback are introduced into numerical computations. Some of these errors can excite the higher‐frequency response of the specimen. In this paper, the use of viscous and numerical dampings to eliminate spurious higher‐frequency effects is studied. Since the tangent stiffness of a non‐linear specimen cannot be measured accurately, initial‐stiffness‐dependent viscous damping is considered. In addition, an explicit integration algorithm with desired numerical damping properties is proposed and examined. The analytical and numerical studies presented indicate that viscous‐damping properties can be substantially changed by non‐linear deformations. For this reason, the use of numerical damping appears to be mo

ISSN:0098-8847    

DOI:10.1002/eqe.4290150403

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractIn this investigation, the coupling effects of the axial motion and other parameters on the bending eigenfrequencies and eigenmodes of laterally vibrating frames are re‐examined. To this end an energy variational approach is performed on a rigid‐jointed triangular frame, whose joint mass is eccentrically located with respect to its theoretical position. The governing partial differential equations subject to the appropriate boundary conditions are very conveniently formulated and successfully solved in a closed form by using generalized functions and Laplace transforms. Contrary to the usual assumptions of the standard dynamic analysis of continuous systems, herein the effect of axial contraction and extension is accounted for when establishing the translational kinematic boundary conditions. This may lead to considerable discrepancies that reveal the decisive role of the axial motion effect on the dynamic response of framed structures. Such discrepancies are clearly confirmed through a thorough numerical discussion of the governing parameters: joint mass and its rotatory inertia, joint angle, positioning of the mass, slenderness ratios, stiffness and length rat

ISSN:0098-8847    

DOI:10.1002/eqe.4290150404

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA finite element technique is developed for two‐dimensional problems of dynamics of dam–water–foundation systems taking into account all interactions rigorously. Water–foundation interaction, which previous developments have only simulated, is considered by imposing proper conditions at the fluid–solid interface. Furthermore, the technique permits treatment of layered foundations. An application to a concrete gravity dam–water–foundation system is presented

ISSN:0098-8847    

DOI:10.1002/eqe.4290150405

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractPresented in this paper is a detailed parametric study of the coupled lateral and torsional response of single‐storey building models subjected to earthquake base loadings. The aim is to assess the influence of torsional coupling on the elastic responses of buildings subjected to transient ground motion records, and to make comparisons with current code provisions which make allowance for coupling effects by means of empirical design procedures. The study of building responses to selected earthquake excitations shows that the qualitative effects of the controlling parameters on the maximum translational and torsional responses of the coupled system are similar to those observed in analyses using idealized response spectra to represent the input ground motion. It is also demonstrated that for particular ranges of the key parameters defining the structural system, typical of the properties of many actual buildings, torsional coupling induces significant amplification of earthquake forces. This amplification is shown to be inadequately accounted for in the current design provisions of major building codes. Recommendations for improving existing design practice for asymmetric structures are outline

ISSN:0098-8847    

DOI:10.1002/eqe.4290150406

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThe effectiveness of the design recommendations made by various major building codes to account for torsional coupling effects is evaluated with respect to the parametric responses to earthquake ground motion of a simple single‐storey asymmetric building model supported on an elastic foundation. The objectives are to determine the extent to which the response trends observed in previous studies of asymmetric rigidly based buildings are affected by changes in the flexibility of the foundation medium and to comment on and suggest necessary amendments to the design recommendations in order that suitable allowance be made for the resultant changes in the magnitude of torsional coupling effects. It is concluded that whilst the qualitative effects of torsional coupling are not affected by soil–structure interaction, their magnitude depends significantly on the frequency content of the free‐field motion. The response to the El Centro earthquake record is conservatively accounted for by assuming the structure to be supported on a rigid foundation. An allowance for increased response effects due to soil–structure interaction is suggested for incorporation in the torsional design recommendations when European earthquake records are e

ISSN:0098-8847    

DOI:10.1002/eqe.4290150407

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290150408

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290150401

出版商:John Wiley&Sons, Ltd    

年代:1987

数据来源: WILEY