In the conventional studies on the seismic behavior of bridge piers, it is common to use an in-plane modeling where the real behavior of frames subjected to the three-dimensional seismic loading is ignored. Herein, we present a three-dimensional nonlinear dynamic analysis for frames, where the panel zone deformation is also considered. In this analysis, geometrical nonlinearity is precisely taken into account by using the co-rotational method, whilst the member plastification is analyzed by the plastic-zone method. With the numerical method, the three-dimensional seismic behavior is examined for bridge piers of single post-type and portal frame-type in which effect of panel-zone deformation is also discussed.

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Kaore arch dam is subjected to forced vibration fields tests with a high water level, with a water level 27m below the crest and with a water level 70m below the crest. Dynamic water pressures are measured with newly developed hydrodynamic pressure measuring instruments and displacements are also measured. Measured frequency response curves and resonating shapes for dynamic water pressures and displacements are simulated by using a finite element model and good agreements are obtained. It's shown that the hydrodynamic pressure measuring instrument is practicable and a computer code for three dimensional dam-foundation rock-reservoir water system is also effective for analysis of dynamic water pressures.

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The ability of neural networks to approximate functions was discussed in this study. The dynamic analysis algorithm using neural networks to evaluate nonlinear hysteretic behavior of high damping rubber bearings was developed. The feedforward multilayer neural network was trained with the cyclic loading test data of the bearing. The neural network memorized the nonlinear hysteretic behavior of the bearing closely. In the next step, the trained neural network was applied to evaluate nonlinear hysteretic behavior of the bearing during an earthquake. The calculated result using the neural network as a subroutine of dynamic analysis was compared with the shaking table test of the bearing. The result closely agreed with the experimental result. The applicability of developed algorithm to dynamic analysis of nonlinear hysteretic behavior was confirmed by this comparison.

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So far many studies have been reported about vibration characteristics and dynamic increment factor of Steel cable-stayed bridges due to vehicle's movement, conversely, there is not any such study concerning PC cable-stayed bridges. Therefore this study is concerned with vibration tests in 2 span continuous PC cable-stayed bridge due to test vehicle's movement. In addition, the simulation of dynamic response was carried out, in which analytical model was made based on the measurement results, in order to compare analytical results with measurement ones. The results of this study showed that dynamic increment factor did not increased, even if the weight of test vehicle increased. It is found that the dynamic increment factor is twice to two and half times as that of the design impact regulation of JRA, when minus bending moment was occurred in cross section under running test vehicle.

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The Hanshin/Awaji Earthquake caused extensive damage to many bridge of the Hanshin Expressway. Especially falling-down of superstructures and other destructive damage occurred at Benten Kouku which locates b downtown of Kobe. After the earthquake, the continuous 19-span space frame bridge with lead rubber bearings which has approximate 565m bridge length was reconstructed in this region. It is the first trial in Japan to use large lead rubber bearings as an isolator or as a damper at the bottom of the steel pier for the purpose of reduction of seismic force acting on this bridge. Therefore this study had vibration tests via a jack. This paper describes the results of vibration tests and make a comparison between experiment and analysis.

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When a structure is subjected to a strong earthquake motion, damage of an upper-structure is immediately investigated by structural engineers. On the other hands, damage of pile foundation is likely not investigated because of economical and technical reasons. A new damage-inspection method for concrete piles damaged by an earthquake has been developed using AE waves emitted from damaged portions of piles. In this paper, a principle of the proposed method, background and hypotheses of this method are discussed. Then, a principal applicability of the proposed method is demonstrated by some laboratory tests. A field applicability is shown by field tests conducted onto real piles broken by a big earthquake.

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This paper discusses a fatigue durability of longitudinally prestressed concrete slabs under running wheel load. The ordinate of S-N diagram is necessary to express the ratio of the applied wheel load divided by the shearing capacity. There are two phases in this paper. In the first phase, the formulae on the punching shear strength of prestressed concrete slabs proposed by the authors are verified about the coincidence with experimental results. In the second phase, a relation between the fatigue lives and the prestressing level is found from the fatigue test results of longitudinally prestressed concrete slabs. As a result, the relation between the fatigue lives up to the serviceability limit state and the effective prestresses is derived. Furthermore, applicability of the S-N curves for reinforced concrete slabs on the S-N data of longitudinally prestressed concrete slabs are discussed.

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The amplification factor due to multiple reflection has been widely used to estimate the characteristics of ground motions. However, as had been observed during the 1995 Hyogo-ken Nanbu earthquake disaster, the amplification of the ground motion due to irregular subsurface topography has to be considered. From this point of view, an incident boundary amplification factor was firstly introduced wherein it was revealed that contributions from the irregular boundary appear not only in the immediate vicinity of the irregular boundary but the whole of the sedimentary region considered in this study. Next, an averaged amplification factor to distributed incident plane waves was formulated, and the amplification characteristics of the ground were estimated from it. It has been concluded that when the incident wave field is not predictable, the averaged amplification factor is more reliable than the amplification factor due to either one-dimesional multiple reflection or an incident plane wave in a ground with irregular subsurface topography.

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Moderately thick perfect cylindrical shells under axial compression first exhibit axisymmetric deformation patterns, where a localization of buckling patterns, i. e. an elephant foot bulge, occurs at the first plastic bifurcation. However, the transition from the axisymmetric buckling mode to a diamond buckling mode may occur due to the next bifurcation if we continue the loading under displacement control. Herein, this phenomenon is examined based on a rigorous plastic bifurcation analysis. As a result, it is observed that the circumferential wave number of the diamond buckling mode increases with the decrease of the wall thickness. It is also found that the strain concentration is intensified for the diamond buckling mode, compared with the axisymmetric buckling mode.

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In this study the effect on the seismic resistance of steel pipe piers of the existence of two different sections, the thickness of pipe plate, loading patterns, and weld residual stresses, were studied. The specimens were made by two different sections, representing actual bridge piers. The elastic-plastic behaviour of steel pipe piers under the following conditions are discussed by experiment, response and FEM analysis. Three different loading histories were used in the experiment, increasing loading monotonically, increasing loading cyclically between tension and compression and pseudo dynamic loading with ground motion data of the Hanshin-Awaji earthquake. As a result, it was found that the modes of buckling and hysterisis curves are strongly influenced by the existence of two different sections and by the loading patterns.

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A solution method for the time-dependent, incompressible Navier-Stokes, and advective-diffusive equations is presented. The method is based on a set of highly accurate superstable time integration algorithms of implicit two step which have been developed by the authors, and finite element equations of the primitive variable formulation. Particular processes regarding the convective terms lead to an iteration algorithm under linear, symmetric coefficient matrices, not to be introduced additionally artificial techniques, as for N-S equations. An unique feature in the advective-diffusive solution is the evaluation process of artificial diffusive matrices.
Numerical examples with vortex shedding behind a circular cylinder are presented to illustrate the features of the proposed method. A spot of the advective-diffusive results is shown in comparison with the integrated streaksheets visualized by S. Taneda

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This paper, aiming at train induced vibrations near the track, analyzed an embankment type track over lying layered soils for a harmonic moving load of a constant speed on it. The discretized wave number solution was first obtained by using the relevant Green function for layered soils under a specific load distribution. The hybrid solution method was taken between the BEM for the layered soils and the FEM for the embankment. The computer simulation cleared the vibration features of embankment and the nearby ground with respect to the dynamic interaction between embankment and underlain layered soils, and the wave dispersion characteristics of the layered soils. Also demonstrated was the wave impeding block (WIB) effect for the response reduction.

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The effects of solid-fluid interactions and gravity on wave propagation in the SOFAR channel are investigated by using a discrete wavenumber and normal mode superposition method. Numerical results show that the arrival time of the gravity perturbated wave which has the largest amplitude is delayed. Therefore, it is possible that the propagation of TSUNAMI is largely affected by the compressibity of fluid as well as the heterogeneity of the sound velocity of fluid. Another effect of the SOFAR channel on wave propagation is in that the fundamental Rayleigh wave shows the anormalous dispersion property.

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This paper aims at an elaborate interpretation of the wave propagation in a soil stratum over rigid base. Such stratum models, in contrast to a halfspace model, have eigenmode waves which are dispersive to frequency. First, the wave field is clarified in reference to the dimensionless frequency-wave number characteristic curves, covering, the wave propagation to the soil vibration. Then, the wave motions due to different loading conditions are evaluated for such as impulse loads and moving constant/harmonic loads. The features of wave propagation/impediment due to the cut-off frequency are confirmed with respect to the depth and shear velocity of the stratum soil, and of the moving speed and frequency of loads.

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The purpose of this research is to represent Green's function for an elastic layered medium in terms of eigenfunctions for the discrete and continuous spectrums. The concept of the energy integral for the continuous spectrum is established to decompose the kernel of the branch line integral into eigenfunctions for the continuous spectrum. The formulation carried out in this paper is based on the physical interpretations, but is not based on the strict mathematical ones. Numerical calculations are performed so as to veryfy the formulation for decomposing Green's function into eigenfunctions for the discrete and continous spectrums. Numerical results show the efficiency of the formulation which is applicable to the engineering problems.

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The present paper deals with the external force of liquefaction-induced lateral flow on an in-ground duct and supporting piles. For this purpose, the author conducted a model shake table test and a static load test. The lateral flow occured like a muddy flow in the soil container. In this reflection, the test results show that the degree of the external forces on the duct and piles are roughly proportional to the lateral flow velocity. Also the external force on the pile can be estimated by drag force utilization. Furthermore, the peak external forces on the duct and pile yield to total lateral earth pressure which can be estimated using the earth pressure coefficient equal to 0.15. This finding is believed to be a lead for developing an earthquake resistant desing practice.

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To verify the seismic isolation effect in the cross sectional direction of rectangular tunnel, model vibration tests were performed. Two 1/25 tunnel models made of acrilyc plates were embedded in the sand layer constructed in the shear stack box on the shaking table. One model was covered by a soft isolation layer, the other one was non-isolated. The test results indicated remarkable reduction of cross sectional forces and tangential earth pressures acting on the isolated model. The authors also simulated the test results using a dynamic finite element method. Good agreement on the seismic isolation effect was obtained between the test and the analytical results.

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Seismic design method for underground structure is proposed taking note of the relative displacement between the ceiling and base slab as the deformation characteristics of the structure. The examination of the seismic performance is carried out by the comparison of the dynamic response deformation characteristics of the structure with the deformation characteristics associated with the damage mode of each member. The major characteristic of this method is that not only the seismic performace of each menber but also that of the structure is exami ned by the comparison between both deformation characteristics. This method was applied to evaluate the damage mechanism of Daikai station, Kousokunagata station and connecting tunnel between Daikai and Shinkaich station at KOBE Rapid Transit Railway which was seriously damaged by HYOGOKEN NANBU earthquake. It is found that this method is useful.

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This paper shows the method of instantaneous optimal control algorithm by using time-frequency domain data derived from real-time wavelet decomposition for seismic wave. To improve the precision of real-time wavelet decomposition, the method using time series prediction model is proposed and its effect is examined. Furthermore, proposed method is applied to feedforward control and its control efficiency is examined by simulation analysis in one degree of freedom system having one control system.

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Optimization of passive energy dissipation devices, such as isolator bearings, to improve seismic performance of elevated bridges is studied. At the first half of the paper, general optimization procedure for seismic response reduction is constructed through approximating the seismic excitation by stationary Gaussian white noise. Following the construction of this general method, optimal design of deck connections and bearings is investigated in details using simple linear two-degree-of-freedom structural models. Analytical expressions for optimal design values are also developed for these devices. The validity of the proposed optimization procedure and design values is demonstrated using the observed ground motions of 1940 El Centro earthquake, and 1995 Kobe earthquake measured at the JMA Kobe Station. Characteristics of seismic response of these controlled structures and limitation of performance improvement by energy dissipation devices are also discussed.

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A new formulation of the finite deformation theory for thin-walled beams is presented by introducing the orthogonal warping functions. The new theory is not only simple and clear but also possible to extend following the many knowledge of the small deformation theory for thin-walled beams. As analytical examples a thin-walled bar subjected to axial compressions and a beam subjected to couples at the ends are treated. The results are compared with known results from stability theory, and perfect agreement is obtained.

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This paper deals with the characteristics of ultimate strength in the form of stress resultants, and then their interaction curves of unstiffened and stiffened thin-walled box stub columns subjected to compression, bending (including biaxial bending), torsion and their combinations are investigated based on an analytical method. This interaction curve for the ultimate stress resultants is verified through a parametric study based on elasto-plastic and finite displacement analysis by using F. E. M.

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Interaction curves have been proposed to predict the ultimate stress resultants of thin-walled unstiffened and stiffened box members due to the local buckling by the authors. The verifications of these interaction curves have already been confirmed through an experimental research by using fourty four specimens. Presented in this paper is an additional experimental study carried out to verify still more the interaction curves. Then, five specimens of stiffened box stub columns subjected to five combinations of compression, biaxial bending and torsion have been tested. Furthermore, the results of the experimental study through fourty nine specimens in total, which were carried out by the authors, are summarized herewith.

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In order to examine the effects of static strength of steel and softening weld material on the fatigue strength, fatigue tests have been carried out on three types of cruciform fillet welded joints, which were made of high strength steel and weld material for the high strength steel, the high strength steel and weld material for mild steel, and mild steel and weld material for the mild steel. Test results indicate that the effects are not significant if the size and the weld toe geometries of joints are the same.

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