This research aims to determine the effect of loading pattern on the damage of a reinforced concrete bridge column. Five specimens were tested with uni-directional or bi-directional cyclic loading patterns combined with a constant axial load. In this report, a simple procedure to predict the damage and failure of a reinforced concrete column, that is subjected to an arbitrary seismic loading pattern, is proposed using the fatigue based damage model combined with the energy dissipation.

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Proposed in this paper is a seismic retrofitting method utilizing carbon fiber reinforced plastic sheets for circular columns in existing steel bridge piers. The method can be considered to be practical and convenient in retrofitting works compared with other current retrofitting methods. In the method, a circular column is wrapped with CFRP sheets of extremely high tensile performance. The validity of the proposed method is investigated through a bending test, compression test and cyclic loading test. It is concluded that the proposed method can control and improve the ductility capacity of the column without increasing its flexural stiffness and ultimate strength. Applications of the method are also discussed.

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This paper deals with the response mechanisms of person trips after the Geiyo Earthquake in 2001 that occurred near Hiroshima, Japan. Such data are essential for post-earthquake road planning and travel demand management after disasters. This survey of person trips was undertaken by randomly sampling 1, 038 residents of the Hiroshima metropolitan region which suffered the brunt of damage. The response in travel demand due to the earthquake was mainly centered on trips transferring from trains to cars, as these activities comprised 38.1% of the amount of diverted travel demand. The response of travel demand often involved young trip-makers and those who are socially active. With information acquired through TV, radio, and announcements, these people undertook the majority of their trips using public transportation. A small number of companions and long trip-distances were also factors. Furthermore, the response was caused by the influence of physical restrictions such as traffic restrictions and suspended transportation services.

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Impact response and radiation of impact sound generated from bridge slabs and its joints under the action of moving vehicles have been one of the environmental noise problems. In view of troublesome nature of impact sound, several authors reported a series of studies on impact noise. However, attention was given to the radiation of residual sound after the impact of a body and a plate.
This paper presents the generation mechanism of impact sound generated from plates subjected to colliding spherical bodies by the acoustic experiment, and the effects of geometric and material properties of plates and spherical bodies on frequency spectrogram of sound pressure have been clarified. The correlation between frequencies of vibrating plates and impact sound caused from plates due to colliding spherical bodies are also investigated. It is found that the peek values of impact sound coursed by the local deformation of plates are dependent on the material and geometry of colliding spherical bodies and plates.

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This paper presents a simple estimation method of the remaining compressive strength for corroded flange plates. Non-linear finite element analyses of compression flange plates with corroded surface generated by the spatial autocorrelation model were performed parametrically using isoparametric shell elements.
From the numerical results, it is concluded that the compressive strength of corroded flange plates can be estimated from the buckling strength curve of corrosion-free plate by using two parameters, t_R=t_avg+2σ_t and e_avg/t_avg, where t_R=representative thickness for rating width-thickness ratio, t_avg=average thickness, σ_t=standard deviation of plate thicknesses and e_avg=average eccentricity.

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The scattered wave field from a crack in an elastic solid is represented by the integral over the crack surface. Introductions of the far-field approximation to Green's function and the high frequency approximation to the crack opening displacement lead to the oscillation phenomena of the scattering amplitudes. The period of the oscillations is utilized to characterize the crack geometry. In this paper, the explicit expressions to determine the length and inclination of the crack are derived from the periodicity of the scattering amplitudes. The versatility of the method is verified from the experimental measurements in the combined use of the pulse-echo and pitch-catch configurations of transducers.

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Firstly, failure mode and shear strength of the stud connectors were investigated based on the push-out test results. Secondly, availability of the proposed analytical method was verified on the basis of the comparison with the test results and the failure mechanism of the grouped arrangement was studied. Lastly, parametric analyses on concrete strength and on the longitudinal spacing of the stud connectors were conducted and equations of the reduction of the grouped arrangement of stud connectors in the shear strength behavior were proposed.

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In 2 dimensional problems, the utility of the vertex rotations on membrance element has been discussed and proved by a lot of researchers. However, up to now, the study of the solid element which has the vertex rotations has not been performed. Therefore, in this work, we propose the tetrahedral element including the vertex rotations based on Cook's assumption and Sekiguchi's, and these elements are applied to the free mesh method which is a kind of mesh-free method. As the result of numerical analysises made in this study, it was found that the accuracy problem of the free mesh method is eliminated by using these elements.

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The authors earlier developed an elastic equation by extending the beam-bending theory while considering the shear deformation of the corrugated steel web, and discussed additional stress induced by the bending acting solely on the slab. Similar additional stress is induced where torsional loads acting on the box girder with corrugated web causes the warping of the slab. In this study, the amount and distribution of the stress were analyzed by the matrix method, which solves differential equations for problems of cross-sectional deformation. The knowledge obtained is so important that bridge engineers should take it into consideration in actual design and construction.

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In order to investigate the responses of a vehicle under strong cross-wind, numerical simulations and driving simulator experiments were conducted. The responses of a vehicle under cross-wind were simulated using a numerical model, which can consider the interaction between the reaction of a driver and the motion of the vehicle. The simulated results showed good agreements with those obtained from the driving simulator experiments. Hence, the responses of a vehicle under cross-wind can be simulated systematically using the numerical model if the parameters for different vehicles are properly determined.

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When the infinite domain is treated in finite element analysis, infinite elements are frequently used to decrease the number of elements. In this study, the hierarchical infinite elements that can obtain highly accurate solutions by few elements are developed. These elements can be applied to curved infinite elements with arbitrary shape by using the hierarchical mapping technique with semi-infinite functions. Furthermore, the singular infinite elements where singularity is introduced into those mapping functions are proposed for the stress concentration in the vicinity of singular points of the infinite domain. By using numerical examples, the accuracy and availability of these elements are demonstrated.

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After the 1995 Hyogoken-nanbu earthquake, real-time earthquake damage estimation systems have been into the national government and local governments. Hiroshima city also introduced such a system and got a opportunity to utilize the system for the first time as a local government at the 2001 Geiyo earthquake.
In this study, we investigated the estimation accuracy of strong earthquake motions which are the base of the damage estimation of the system. There were large difference between observed earthquake motions and estimated ones at some recording sites. The three main reasons of the differences are as follows; first, the difference of spectral characteristics in the high frequency range of the estimated motions from the observed ones, second, extrapolation technique which is used to estimate the distribution of ground motions from observed ones, third, the variation of modeling the surface ground to estimate the ground motions.

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Engineering structures are often subjected to dynamic loads, such as earthquakes, winds or sea waves, which are most appropriately characterized as random processes. In the past much effort has been paid to evaluate the first excursion probability of randomly excited nonlinear dynamical systems. However, analytical solutions are available for a restricted class of systems only, whereas Monte Carlo simulation technique offers a feasible alternative for solution of first excursion probabilities except prohibitive computational costs. This paper investigates the variance reduction technique, which is the importance sampling technique utilizing the measure transformation method for the non-linear dynamic system. To attain the purpose, the importance sampling function is obtained by using the stochastic terminal state control theory. The efficiency of the proposed method is demonstrated by numerical examples of non-linear restoring force systems under the external white noise excitation.

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It is known that the bending moment of pile foundations is generated not only by the inertial interaction due to superstructure, but also by the kinematic interaction due to large deformation of soft soil layers. Therefore, it is highly necessary to investigate the characteristic of kinematic pile bending. The present study focuses on the appropriate diameter of pile foundations affected by the kinematic interaction. In this research, the relation between the diameter of pile and its bending strain is evaluated based on theoretical approaches and the seismic deformation method. As a result, the inadequate diameter that maximizes the kinematic pile bending strain is found and its characteristics are investigated.

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The authors investigated into the fundamental characteristics of the external loads on foundation piles from flowing liquefied soil based on the experimental results under a centrifuge condition. The followings were obtained as conclusions; The viscous load depending on the ground flow velocity of liquefied soil was dominant on the piles when model ground was completely liquefied. On the contrary, the external load resulting from ground displacements was governing the pile deformation when the model ground was not liquefied or partially liquefied. Furthermore, when a non-liquefied soil was overlaying on the liquefied soil, an external load due to ground displacements of the non-liquefied soil was dominant.

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A new numerical simulation method for analysis of failure phenomena, namely, FEM-β, is proposed. This method can be regarded as FEM (finite element method) with special displacement field (discretized by discontinuous, non-overlapping shape functions).
Particle physics model for continuum body formulated by FEM-β can easily deal with failure phenomena and keeps equivalence to FEM in its accuracy and sparsity of the stiffness matrix. In this sense, FEM-β can also be regarded as reformulation of DEM (distinct element method) in the framework of FEM which gives rigorous inter-block spring constants to DEM.

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Service structures, such as sign structures and lighting poles installed on highway bridges, are often subjected to stress cycles due to traffic-induced vibration, and this causes fatigue problems. Vibration and stress measurements were carried out for frame structures on a viaduct. The viaduct was structurally modified from a simple girder to 3-span continuous girder to increase seismic resistance. The natural frequency of the first bending mode of the simple girder of 3.78Hz decreases to 3.58Hz with elastomeric bearing and 3.58Hz for 3-span continuous girders. Fatigue life calculated from stress range histogram was reduced, when the natural frequency of the viaduct was near to that of the service structures.

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By utilizing ripple web (waveform), high degree of shear buckling strength can be obtained. Therefore it is possible to reduce the thickness of the web. As the lighter self-weight of the superstructure is attained, the economic efficiency of the bridge is obviously achieved. Furthermore if the high strength steel is used for the lower flange, this new structural type provides more economical design for bridges. However, in girder bridges with ripple web, high stress concentration occurs at the welded joint between the corrugated web and lower flange. It is thought that this stress concentration would cause fatigue problems. In this research, stress conditions and fatigue performance of girder bridges with ripple web were discussed by using FEM analysis and static loading tests and fatigue tests for large-scale specimens.

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Steel arch bridges constructed before the Kobe earthquake were designed with only moderate earthquake consideration, and they may suffer severe damages if subjected to major earthquakes. Seismic performance upgrading and retrofit approaches are of great significance for aseismic consideration against major earthquakes. Presented in this paper is a seismic performance upgrading approach for steel arch bridges using buckling-restrained braces as dampers. Inelastic behaviors of a representative steel arch bridge with buckling-restrained braces subjected to the major earthquake are investigated by three-dimensional modeling time-history analyses, and compared with the result from the original structure. It is found that replacement of diagonals of some parts by buckling-restrained braces can greatly improve seismic performances of the steel arch bridge. As a result, this approach is believed to be an effective way for seismic performance improvement of new bridge designs as well as retrofit of existing ones.

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The present study focuses on impedance functions at the head of single pile foundations that support bridges and viaducts. It is predicted that slippage and separation occur at the interface between soil and the pile foundations when subjected to strong motions. Therefore, it is desirable to know the effect of slippage and separation on the impedance functions. This study investigates the characteristics of the impedance functions by means of analytical approach based on a three-dimensional wave propagation theory, including the influence of inertial and kinematic interactions. The present study gives physical understanding of the effect of slippage and separation upon the impedance functions.

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The authors have already investigated the structural performance of the energy-dissipating structural system with hysteresis braces (Damper Brace) by analyses and verified the hysteresis properties of Damper Brace by experiments. However for implementing the systems to bridges, it is important to verify the effect of reducing structural response under a ground motion. In this paper, seismic response tests were conducted with a scaled model of abutment structure in which Damper Braces were installed. As a result, it was confirmed that the seismic response of the model reduced significantly comparing to the standard structure without Damper Braces and that the Damper Braces had good energy dissipation during the excitation.

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This study examined corrosion characteristics and durability of painted steels with different surface preparations of steel substrates through accelerated exposure tests. Steel plates were fabricated with structural steels for twelve specimens and weathering steel plates for twelve specimens conforming to JIS SM490A and SMA490AW, respectively. Nine of the twelve plates in each group were pre-corroded in the accelerated exposure test equipment for S6-120 cycles (30 days), and then the surface treatment of the pre-corroded specimens was conducted by a grinder in three ways, i. e. complete rust removal, slight rust removal, and no rust removal in each for three corroded specimens. Non-corroded steel plates were grit-blasted before coating. Based on C-3 or C-4 painting systems, the coating of all the plates was performed. The accelerated exposure tests of the painted specimens were continued for S6-1000 cycles (251 days). From the test results, the effect of different surface preparations degree on corrosion deterioration of the painted steels was clarified.

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The present paper discusses characteristics of coupled cable vibration and its effects on damping of the Tatara Bridge, the world-longest cable-stayed bridge at the moment, by the theoretical modal analysis based on the substructural synthesis and also by the experimental modal analysis based on the Eigensystem Realization Algorithm.
It is found through this study that many numbers of cables' local modes can be coupled with the principle globalmodes of long-span cable-stayed bridges, which can reduce the damping ratios of the global modes of bridge due to low damping characteristics of the stay cables.

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Tokaido Shinkansen plays a major role in the domestic transportation system, while in some cases it gives rise to noise and vibration problems in the wayside. Many efforts have been made to solve the problems, but practical measures for reducing the vibration to acceptable level are not developed until now. This paper proposes a new vibration reduction method applicable to rigid frame bridges with cantilever girders adopted in urban areas. At first, field vibration measurement is made and a numerical analysis tool is developed to simulate the traffic induced vibration. Based on the field measurement and numerical study, a new method that rigidly connects the cantilever girders is proposed and the practical structural system is carefully designed. The new measure is installed to an actual rigid frame bridge. The numerical as well as field investigation shows satisfactory behavior for the reduction measure. Successful agreement of field data in the effectiveness with numerical ones is also confirmed.

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Tuned Rotary-Mass Damper (TRMD) is a type of passive dynamic damper which can reduce the vibration of the structure by using the control power generated by the rolling movement of a rotary-mass. In order to verify the effectiveness of TRMD, we applied TRMD to the vibration of a lighting pole on a highway bridge. The 2nd inplane vibration mode of the lighting pole was resonant with the vibration of the highway bridge caused by the vehicles. As a result of the application of TRMD, the vibration of the lighting pole was reduced. In addition, we measured the strains near the base of the lighting pole and determined that the fatigue life of the lighting pole was extended.

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The effect of plate thickness on fatigue strength of the out-of-plane welded gusset joints was investigated through out-of-plane bending fatigue test and 3-D finite element analysis for the joint specimens made of JIS SM570 high strength steel plates of 25mm and 75mm thicknesses. The specimen with the thickness of 75mm has such a lower fatigue limit as about one-half or one-third of that of 25mm thick joint under out-of-plane bendeing, because of its very high stress concentration at the fillet weld toe. Finally, the authors proposed the correction factor for fatigue strength of the out-of-plane welded gusset joint taking account of thickness effect under both of out-of-plane bending and tensile loading.

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If fatigue damage or its possibility can be estimated easily and economically, the efficiency of maintenance inspection for steel bridge is considered to be drastically advanced. For this purpose, a system was developed, in which thin stainless steel with a fatigue crack is stuck on a real bridge to measure crack propagation and the cumulative amount of fatigue damage. In this study, high sensitive monitoring sensor is proposed in order to accumulate the crack propagation and shorten the monitoring period, and an evaluation formula for estimating the acceleration is developed. Furthermore, the validity of the formula is examined through stress intensity factor analyses and fatigue crack propagation tests.

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