摘要:

AbstractA generation procedure of Ritz vectors to control the inclusion of static effect and the number of vectors in mode superposition dynamic analysis is presented. The original algorithm of the Ritz vectors15is modified to improve stability in the generation procedure and to include the use of static residual. To reject unimportant Ritz vectors, cut‐off criteria, which are based on the participation of mass distribution and spatial load distribution, are proposed. Numerical examples are presented to illustrate the effectiveness of the derived Ritz vectors over the eigenvectors and the performance of the cutoff criteria in the mode superposition dynamic analysi

ISSN:0098-8847    

DOI:10.1002/eqe.4290180203

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe bulging observed on the wall of a ground supported cylindrical storage tank, located at the Chiba Experimental Station of the University of Tokyo, is investigated. This damage is correlated with a ground motion recording obtained very near the tank base during a moderately strong earthquake that occurred on September 25, 1980 not far from the Chiba Experimental Station. From this correlation the importance of the horizontal excitation in amplitude and direction is clearly established. In addition, good agreement can be seen between the predicted tank wall earthquake performance, derived by an empirical approach proposed by the first author, and the shell deformation observed at the Chiba Experimental Station.

ISSN:0098-8847    

DOI:10.1002/eqe.4290180204

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAsymmetric steady‐state structure‐media interaction due to obliquely incident body waves is investigated via a version of the global local finite element method. In the present version, a local region that houses an axisymmetric structure is modelled by conventional finite elements, while the behaviour in the remaining portion of the homogeneous semi‐infinite medium is presented by the spherical harmonics that are the eigensolutions of the entire space problem. The solution scheme involves (1) full displacement and traction continuity along the boundary between the local and the exterior regions and (2) satisfaction of the traction‐free requirement on the surface of the half‐space beyond the discretized region by virtue of a sequence of integral constraints of the non‐zero weighted surface tractions of the spherical harmonics. The numerical results presented are for a perfectly bonded rigid circular foundation resting on the surface of the half‐space and subjected to obliquely incident body waves. Dependence of the displacement response of the footing upon incident angles and dimensionless wave numbers is thoro

ISSN:0098-8847    

DOI:10.1002/eqe.4290180205

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractExpressions for both the rectilinear and rotational inertial and damping coefficients for a circular monolithic tower of uniform radius are derived. The analysis matches the fluid velocity, derived from potential theory, with the structural velocity in sway. That is, the motions of the tower are assumed to be in a vertical plane. The analysis is then applied to a tower composed of (lumped‐mass) elements, where the expressions for the added‐mass and damping coefficients are shown to be functions of wave number. The added‐mass is shown to be a product of two wave systems: a travelling wave system, which is responsible for the radiation damping, and a standing wave system, called the evanescent system, which is attached to the structure.The added‐mass of the evanescent system is negative for small wave numbers, while that of the travelling waves is positive. The negative sign simply means that the inertial force of the evanescent waves is 180° out of phase with that of the travelling system. Furthermore, it is shown that the contributions of the two wave systems to the total added‐mass of the structure counteract each other, resulting in a total added‐mass which varies gradually with the wave number.Finally, the analysis is applied to an experiment, and results of the analysis and the experiment are found to agree

ISSN:0098-8847    

DOI:10.1002/eqe.4290180206

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe reduction of the spectral accelerations to account for inelastic response of structures as given by the 1976 Regulations for the Federal District of Mexico is evaluated relative to the records obtained at the Secretaria de Communicaciones y Transportes (SCT) during the September 19, 1985 Mexico earthquake. It is concluded that the 1976 Regulations do not treat all types of structural systems equally. On a relative basis the 1976 Regulations provide less protection for those structures designed to larger values of ductility factors. This could have contributed, together with other characteristics of the ground motions and construction practices, to the heavy damage of highrise buildings in Mexico City.

ISSN:0098-8847    

DOI:10.1002/eqe.4290180207

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractIn this study a mathematical model is proposed to predict the non‐linear in‐plane behaviour of clay brick masonry walls when subjected to dynamic excitations. Owing to its length, the study is divided into two parts. This part is devoted to a description of the appropriate experiments and to the development of the mathematical model, including use of experimental data. In Part 2 the model is completed by establishing the parameter functions appearing in it.The form of the non‐linear model is established by developing a simple, linear model from more complicated ones previously developed by the authors, and then extending this simple model to cover behaviour in the non‐linear range. The model contains two types of parameter function. One describes elasto‐plastic stresses and depends on strains; the other describes viscous stresses and is a function of strain rates.The experimental work was carried out using the shaking table of the Earthquake Engineering Research Center, University of California, Berkeley. The experiments involved in‐plane horizontal earthquake excitations. The intensity of excitation, starting with a small value, was increased gradually through the beginning of cracking until damage was complete. Time histories of accelerations and displacements relative to a fixed frame were recorded at the upper and lower edges, and at the mid‐height of the wall specimen.At the end of this part, the experimental data are processed to obtain the data for a ‘complex frequency response function’ of the wall specimen. The reduced data will be used in the optimization a

ISSN:0098-8847    

DOI:10.1002/eqe.4290180208

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractIn this part, the parameter functions for clay brick masonry appearing in the non‐linear model are established for the wall material used in the experiments by means of experimental data and a particular type of optimization. This special optimization makes use of the fact that the wall behaves linearly at the intensity level of each excitation, as described in Part 1, and involves matching in frequency space the experimental and theoretical complex frequency response functions relating the Fourier transforms of the top and base accelerations of the wall.It is found that the envelope curves for the parameter functions are bilinear and that the dynamic values of mechanical properties of masonry differ greatly from their static values.The completed model is appraised by comparing how the wall will respond to strong earthquake excitations when predicted using the model and how it actually responded on the shaking table. The predicted response is remarkably close to the experimenta

ISSN:0098-8847    

DOI:10.1002/eqe.4290180209

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractTraffic and wind excitation has been used to obtain the dynamic characteristics of the first Bosporus (Bogazici) Suspension Bridge. Structural symmetry and the absence of suspended side‐spans allowed attention to be focused on the main span and the Asian tower. For the main span, 18 vertical and 20 lateral modes were obtained, including torsional modes. For the tower, 12 longitudinal and 12 lateral modes were identified. All these models lie in the range 0–1‐1 Hz.A detailed comparison is given between these modes and corresponding calculated modes, obtained by use of a three‐dimensional finite element model which includes a geometric stiffness matrix. Of particular interest is the validity of the theoretical model used for the box‐deck, because of its subsequent use in response studies of asynchronous seismic excitation.Comparison with a more limited study made in 1973 shows that the bridge continues to behave as it was designed to behave, particularly with regard to the deck‐tower interface. From natural frequency measurements of two hangers, the load which they carry w

ISSN:0098-8847    

DOI:10.1002/eqe.4290180210

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractScattering of elastic waves by inhomogeneous and anisotropic bodies in a half space is considered. The integral equation method is formulated by using the fundamental solution of a homogeneous isotropic body in elastostatics and regarding the resulting inhomogeneous terms as equivalent body forces. Numerical examples are presented for the wave scattering by inhomogeneous and/or anisotropic alluvial valleys and for the dynamic analysis of an inhomogeneous dam. The effect of inhomogeneities and anisotropy on the dynamic behaviour of alluvial valley and dam is discussed.

ISSN:0098-8847    

DOI:10.1002/eqe.4290180211

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290180212

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY