Analytical parametric study on dynamic characteristics of steel tower of cable-stayed bridges is performed to investigate the individual influence of different design aspects, such as damping mechanism, input ground motion, allowable initial construction imperfections, energy dissipation and tower modal shapes. The results show that the horizontal beam height and length and the low yield energy dissipation system significantly affect tower structural behavior. The initial imperfections within design range have slight detrimental effects on the tower seismic response but these effects grow rapidly beyond the design range. Mass proportional damping leads to overestimate tower axial forces and acceleration response.

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Realistic simulation of the mechanical behavior of concrete and reinforced concrete structures is performed by using a lattice type numerical model. Five different types of lattice members with simple constitutive models are introduced for mortar, coarse aggregate, steel, aggregate-mortar interface and steel-concrete interface. The meso-scopic morphology of concrete, which can be realized by the image-based geometry modeling technique, is taken into account. By the incorporation of the accurate meso-scopic morphology into the lattice type numerical modeling, the cracking behavior induced by the meso-scopic heterogeneities has been successfully captured.

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For seismic evaluation of upper-deck type steel arch bridges subjected to Level 2 ground motion, the influence of varying axial forces and bi-axial bending moments should be accounted for in the analysis. Moreover, due regard has to be paid to the integrated behavior of the superstructure composed of concrete deck, slab anchors, and stiffening steel girders. In this study, with a deck model considering both the nonlinear material characteristics of concrete and the reinforcing bar and the sliding behavior of slab anchor, transient response analyses are carried out by using the 3D fiber model. From the analyses, seismic behaviors of upper-deck type steel arch bridges are demonstrated. Furthermore, on this basis, a retrofit method by using a hysteretic damper is proposed for such structures.

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If railway bridges suffer damages by earthquakes, appropriate train control and repair work according to damage levels have to be determined. In this study, a new method to evaluate the damage levels of RC rigid frame bridges is suggested. The decrease in stiffness of the bridge under damages and decrease in the natural frequency with increase in response ductility factor were grasped using the reversal cyclic loading test for half-scale model of the standard type rigid frame bridges of the Tokaido Shinkansen. As a result, it was found possible to evaluate the damage level of bridges by measuring their natural frequency using the dynamic percussion test. And a new rational method to evaluate the damage levels from decrease rate in stiffness of bridges obtained through frequency analysis and response ductility factor calculated by push over analysis of structural members is proposed. These proposed methods were erified through the site tests of the real railway bridge planned to be removed.

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The experimental study is carried out, in which the full-scale models using the perfobond rib shear connectors and the angle shear connectors are used, in order to investigate the mechanical behavior of the shear connectors including the headed studs. From the experimental results, the fundamental properties of these shear connectors are cleared, that is the strain of the shear connectors, the quantity of the opening between concrete slab and steel girder, the shear failure mechanism of the concrete slabs and so on.

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Strong ground motion of the 1948 Fukui earthquake was studied. Using discontinuous FDM grids and dynamic model, the effect of 3-D structure and dynamic source process was considered. The fault was assumed to be strike slip with relatively simple rupture process on a vertical plane. The velocity motions calculated by considering the two processes, i. e. the fault rupture process and the amplification process by sediment, were compatible with the observed directions of fall and collapse. However, the results disagreed slightly in the northern part. The simulation in the northern part might be improved by incorporating the role of dip angle and dip slip of the fault into the analysis.

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In this study, the investigations were conducted on the required fracture toughness of steels to prevent brittle fracture during earthquakes in steel bridge piers. By considering the scenarios of the occurrence of brittle fracture, the patterns of prestrain that should be considered were shown, and then the effects of various patterns of prestrain on fracture toughness of steels made to be clear by the development of the method to introduce prestrain into specimens. Finally, by arranging all the results of this study and our previous study on the effects of plastic prestrain, the level of the required fracture toughness was suggested. To prevent brittle fracture during earthquakes, the temperature shift of 50 degrees of Celsius of the critical CTOD curves by plastic prestrain should be considered.

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Ultrasonic test will be applied to evaluate welded joints of steel bridges. As the recent tendency of bridge construction, 2 or 3 main girder bridges are constructed. Flange plates of those bridges are welded at site. Automatic ultrasonic test (AUT) will be applied for the evaluation of field welded joints. However, there are not appropriate specifications for AUT. A collaborative study was started. The final goal of the study is establishment of AUT specifications for welded joints of steel bridges based on performance-based design. As the step of the study, round robin test was carried out. This paper describes the outline of the round robin test.

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The authors developed a dynamic interaction analysis program for Maglev vehicle and guideway structures. In this program, the Maglev vehicle is three dimensionally modeled as having a body, a truck, and a superconducting magnet connected by springs and dampers. The structures are modeled by three-dimensional finite element method.
Using this program, it was carried out that the second resonance to the first horizontal bending mode of the twin beam is caused at 400km/h and the vibration of the Twin Beam exerts the influence only by about 1.0dB at the riding comfort level of the vehicle. By the train running examination up to 500km/h in speed, it was clarified that the partial bearing was able to control a dynamic response to 1/3.

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Mathematical models of the failure behaviors of a rubber material and the laminated rubber bearing are studied. At first, the mechanical behaviors of rubber failure are investigated through shear and tension experiments of the material. In these experiments, an image processing is utilized to trace the deformation field of the specimens accurately. Then, based on the experimental results, a failure criterion is proposed and it is verified in comparison with the results of the failure experiment of a laminated rubber bearing. Finally, utilizing the proposed failure criterion, design equation for the failure of laminated rubber bearing is proposed. This equation also shows good agreement with the experimental result of a bearing.

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There are a lot of previous studies which have introduced the Huber's hypothesis on the torsional stiffness for the orthotropic plate analysis. However, research of the general slab with arbitrary bending and torsional stiffness has seldom been reported. In this paper, authors carry out three-dimensional finite element analysis in order to obtain the bending and torsional stiffness of symmetrical circular voided slab as an example. The results prove that Huber's hypothesis is not always accurate. Then, we acquire the series solution of the orthotropic plates with arbitrary torsional stiffness under uniform load. The analysis is conducted under 3 cases boundary condition.

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Strong motion indices such as the instrumental JMA seismic intensity provide important information in earthquake emergency management. Because observed seismic motion is strongly affected by site response characteristics, some estimation procedures are necessary to obtain spatial distributions of these indices. Microtremor observations were conducted at 116 seismic stations in Hyogo prefecture. After confirming that the horizontal-to-vertical (HIV) Fourier spectral ratio of microtremor can express the site response characteristics, a method to estimate the JMA seismic intensity was proposed using the ratio of H/V spectral ratios of microtremor and a strong motion record of the reference station, and its accuracy was compared with other exiting methods.

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A dynamic response analysis method for evaluation of the maximum and residual displacements of steel piers or frames with box sections is proposed. A “plastic deteriorating hinge” is defined as a deteriorating area in the stiffened plates, which is due to local buckling. The buckling stress, the softening stress-strain relation and the decrease in unloading stiffness of a plastic deteriorating hinge are formulated from FEM studies with shell elements, and they are implemented in the stress-strain relation of a beam element.
The maximum and residual displacements of steel frames are successfully predicted by finite displacement analyses with such beams, which can be used for evaluation of seismic performance of existing steel frames.

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This paper addresses an evaluation methodology for function of a transportation network in emergency injured transportation. In the post-earthquake emergency response phase, the traffic time delays due to damage of the transportation system has a significant effect on the earthquake casualty. The index of life-saving performance is proposed in the term of survival ratio of injured people. The simulation of injuries transportation has been done by a decision detecting the fastest destination to a hospital, considering both malfunction of transportation system and hospital, which can accept the injured people.

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Required computational domain size was investigated and new boundary treatments and numerical solution method were proposed for the numerical prediction of local wind in complex terrain and were verified by a wind tunnel test. The effect of computational domain height, width and the position of the inlet boundary on the flow field was examined. Buffer zones were added at inlet, outlet and side boundaries, in which the volume of the terrain is maintained. An additional domain was introduced at the windward of the analytical domain to take the effect of the upwind terrain into account. Numerical methods for linear equation systems were examined in detail and new method was proposed, which was found to be fast and stable. Comparison of the mean wind velocity field between the numerical predictions and the measurements shows that the proposed nonlinear model is significantly better than the conventional linear model.

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In aseismic design or seismic damage prediction, it is important to grasp the surface ground characteristics which affect dynamic behaviors of the structures during earthquakes. This paper describes an identification analysis method of the surface ground characteristics using horizontal array earthquake observation records. It is based on the assumption that each incident wave of neighboring observation points in the common basement deconvoluted by the multiple reflection theory almost agrees. The method is applied to a practical problem using actually observed earthquake records, and the validity of the results is examined through the comparison with results by the other method. Because the horizontal array observation can be carried out easily in a wide field, the analysis method proposed here should can make a contribution to improvement of the accuracy of aseismic design or seismic damage prediction. However, the surface ground structure must be roughly grasped to evaluate the incident wave in the basement.

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Recently, a developed form of the PC box girders using corrugated steel web are flourishingly under construction at many sites. The form begins to be used for the continuous girders and the usage expected to be developed even for the cable stayed bridges. Since the corrugated web does not possess rigidity along the span axis, the influence due to shear deformation strongly appears under bending. The authors have developed an elastic equation extending beam-bending theory considering shear deformation. Expanding the equation, the advanced structural analysis by the theorem of dual three-moment method and the CWB (Corrugated Web Beam) matrix displacements-method are formularized. The knowledge introduced through the analysis is so important that the practical bridge engineers should take it into their consideration.

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This paper is to propose an efficient method of three-dimensional dynamic analysis for multi-layered elastic systems with non-proportional damping. Since such problems have high degrees of freedom, computational efforts become enormous when a direct integration method is utilized. Ritz vectors are introduced to reduce a system of equations of motion, which is solved analytically with the use of eigenvalue analysis. It is confirmed that the system of equations with over 25000 degrees of freedom can be reduced drastically to the system of 10 equations without a loss of the accuracy. It also becomes apparent that the accuracy of sensitivity analysis can be improved with the increase in number of Ritz vectors.

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Peak ground acceleration of K-NET, KiK-net records of the 2000 Ishikawa-ken seiho-oki, Japan earthquake were relatively large and regionally biased. Its causes were examined from source effect of the earthquake, path and site effects in the Hokuriku region. We clarified that the relatively large peak ground accelerations were caused from the relatively large stress drop of this earthquake. The spatial distribution of peak ground acceleration seems to depend on differences of Qs-value and site effect in each region.

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We investigate the behavior of scattering waves generated in the ground with topographic irregularity in relation to eigenmodes derived from Rayleigh wave characteristic equation. The pole of leaking mode, which is derived from the characteristic equation, is on a Riemann sheet with which are not satisfied the radiation condition. The behavior of the leaking mode can be interpreted as relation between the incidence and reflection of P wave or SV wave. The responses of surface displacement obtained from the wave propagation analysis by boundary element method are expanded in a series of components whose amplitude are predominantly large in terms of the wavenumber. The influence of leaking mode appears in a Riemann sheet which is satisfied the radiation condition across a branch cut. It is found that Rayleigh wave is main component of the scattering wave and the ground response near the edge is influenced considerably from the leaking mode.

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In the design of railway bridge crossing over road or river, the height of bridge from the lowest portion to the railway level is sometimes restricted by the height of the road or the high-water-level of the river. In order to satisfy these conditions, the authors propose an application of Steel-Reinforced-Concrete (SRC) slab structures to floor system in through-truss bridges. Since the behaviors of this type of bridges have not been clarified, pull-load and dry-shrinkage experiments of concrete slab structure are conducted in this study. These experiments demonstrate the location of cracks in the slab concrete, their developing patterns, and the axial assignment-force of lower chord member.

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In this study, in order to investigate the effects of various boundary conditions on the impact behaviors of Reinforced Concrete (RC) beams under impact loadings, falling-weight impact tests were conducted on 22 simply supported rectangular RC beams and the following effects of the boundary conditions were discussed: 1) use of supporting apparatus; 2) measuring method for impact loads; 3) use of absorber with a hard/soft rubber; 4) nose-shape of steel-weight. From this study, it can be found that the dynamic responses of reaction force and mid-span displacement of RC beams may be similar, irrespective of the use of absorber with a hard/soft rubber and the nose-shape of steel-weight.

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The present study focuses on input loss of deeply embedded foundations that support bridges and viaducts. In recent years, deeply embedded foundations have been longer and of various diameters so that flexural movement of sidewalls presumably dominates in the foundations. Therefore, it is highly necessary to investigate the influence of the flexible sidewall on input loss. In the previous studies, however, the characteristic of input loss has been frequently evaluated under perfectly or compatibly rigid body conditions. Therefore, the present study reveals the characteristic of input loss affected due to the flexibility by means of a closed form solution derived based on a three-dimensional wave propagation theory.

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In order to investigate the suppression mechanisms of the vortex-induced vibration of a circular cylinder by applying periodic velocity excitation to the flows around the cylinder, numerical simulations of the flows were carried out. The vortices induced by the periodic excitation with a high growth rate merge frequently behind the cylinder, and then these vortices change the unsteady lift phase. Such intermittent change of unsteady lift phase stabilizes the cylinder aerodynamics.

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This paper proposed the rational design method of seismic unseating prevention cables for bridges based on their response velocity. The present design load of unseating prevention cable is determined based on the beam weight and the dynamic response of the bridge is not taken into account. In this paper, the demand strength and the sectional area for the unseating prevention cable were derived from the law of conservation of energy. Then, the shock stress was calculated for the designed cable, as its activation should cause the shock wave. Furthermore, the rigidity of the shock absorber was derived based on the cable rigidity and the limitation of its deformation. The numerical simulations also were conducted to estimate the efficiency of the proposed method. The results showed that the cables designed by the proposed procedure were fit to prevent the girder from unseating.

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Performance-based design has been prevalent, in which new technology can be easily configured, compared with regulation-based design. In the guard fence design, a new code under the performance-based design concept was implemented and issued in April 1999 in Japan. Also, the environmental problem has become a serious issue in civil engineering field. It is necessary for the researchers and the engineers to pay attention to the environmental impact in addition to the function, safety, cost and aesthetics at all lifecycle stages. In this study, the problems in the guard fence design are first investigated. Taking the results into account, an integrated performance-based design system of bridge guard fences with low environmental impact is developed. It is shown that the system enables us to design the guard fences having high environmental performance and safety performance.

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Strength of corroded galvanized bridge wires were studied in this paper. Galvanized wires were wrapped with wet gauze and kept at high temperature, producing corroded galvanized specimens in different corrosion levels. Actual tensile strength of the corroded wires did not depend on the corrosion level. On the other hand, elongation and torsional strength decreased sharply after the zinc layer consumed and the steel started corrosion. It was estimated that this deterioration was caused by the surface roughness due to corrosion. This was verified by the tests which showed that elongation was recovered after the surface roughness of corrosion was smoothed. Volume of hydrogen absorbed in the corrode wires was measured, indicating that it did not reach a level to cause embrittlement.

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In this paper, investigation on dynamic properties of concrete is performed. 9 RC specimens were tested by impact acoustics. Longitudinal, flexural and torsional resonant frequencies were measured and examined by a three-dimensional eigenvalue analysis. It is concluded that the number of reinforcement steel-bars in cross-section is less than two, the analytical resonant frequencies in the case are well consistent with measured results. Otherwise, because the stress-strain relationship of concrete around reinforcement becomes complicated, the analytical results are obtained as higher than the measured. Therefore, the theory of one-dimensional elastic vibration is applied, and a numerical formula for solving dynamic properties of concrete is proposed.

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As a versatile tool to update random fields, Bootstrap filter/Monte Carlo filter is focused that is a sequential algorithm of generating a set of sample realizations of a predicted state vector and a filtered state vector respectively.
In order to clarify the potential of this method, stochastic interpolation of a lognormal spatial random field is demonstrated by using numerically simulated data.

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