Coastal revetments are required to keep a designated height to protect the hinterland from damage due to tsunami after an earthquake. This paper proposes a new type of steel sheet pile wall which consists of long and short piles. Only long piles are embedded in the non-liquefiable layer, and consequently, the proposed sheet pile wall has many openings between them. Liquefied ground behind the wall allowed to pass through the openings. The wall, therefore, turns aside the pressure from the liquefied ground, and the height of the wall can be secured. In this paper, the applicability of this type of sheet pile wall is discussed based on the results of experimental and numerical studies. Furthermore, simulation method of bending moment of piles to design a specifications of sheet piles is verified.

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 The soundness of structural stability of railway bridge substructures, which is designed by bearing capacity of foundations and stiffness of a pier body, deteriorates over time because the riverbed and overburden that support the substructures can be gradually eroded by river flow and be affected by neighboring construction. The soundness is diagnosed by the size of natural frequency of a primary vibration mode of a pier identified by measuring free vibration of the pier loaded by an impact force, which is called the impact and vibration test. However, it is required that a more efficient method by using long term monitoring because the impact and vibration test requires considerable labor, and also, with such a field test, it is impossible to perform a continuous diagnosis and therefore a change in the soundness can be missed. In this study, the applicability of soundness diagnosis indices for the long-term monitoring with area ratio of acceleration power spectrum of microtremors and ratio of amplitude of acceleration during train passage was investigated through experimental model tests and in situ measurements. Consequently, it was confirmed that there was a correlation between the indices and the natural frequencies of the piers. The soundness diagnosis of the piers was performed by using the size of indices measured from the long term monitoring. Additionally, the methodology to predict the future change in the area ratio of acceleration power spectrum of microtremors was proposed by using a three dimensional frame analysis.

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 After the 2011 off the Pacific coast of Tohoku Earthquake, contents for seismic assessment of transmission towers far exceed the assumption of the past assessment. Limit state evaluation is performed for the seismic assessment of transmission towers during Level 2 earthquake motion, and the importance of damping constant increases in evaluating seismic performance. The purpose of this paper is to investigate the equivalent damping constant used for seismic performance evaluation of transmission towers with a new kinetic energy absorption device. That is, the kinetic energy absorption performance of lead filling shear bolt joint is examined by material tests on lead and cyclic loading tests of the joint model. Furthermore dynamic response analyses using a transmission tower model with the damper are executed under two Level 2 seismic motions, and the effectiveness of the damper is confirmed.

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 Accelerometers, easy to install and inexpensive, could play an important role in status monitoring of civil engineering structure. When they are installed on a bridge, the dynamic displacement response under live load can be found by double integration of the acceleration time history observed by the sensor installed, which helps us to estimate the local damage and cause of the damage. However, as acceleration time histories are integrated to the response, measurement error of accelerometer has an large negative effect on the result. Moreover, it is very difficult to determine the boundary condition because bridge under live load vibrates at all times.
 In this study, firstly, the effect of measurement error of accelerometer on the accuracy was mathematically revealed. Secondly, we proposed “FREE VIBRATION METHOD”. Assuming bridge is vibrating with its natural vibration before and after vehicular pass, displacement and velocity can be calculated. The velocity and displacement while vehicular is passing on the bridge are calculated by using initial and terminal conditions estimated above. Finally, we conducted the measurement on an actual bridge to examine the effectivity of the proposed method.

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 The purpose of this research is to assess structural parameters such as aspect ratio, plate slenderness parameter and flange web thickness ratio of shear panel damper on the seismic performance of multi-pipe integrated bridge pier originally proposed by Hanshin expressway corporation for further development. In this research, FE analytical model were constructed based on the experimental results for the real scale shear panel damper of the pier. And then cyclic and seismic response analyses for various the structural parameters were carried out to investigate the cyclic behavior and energy absorption performance of the shear panel analytically.
 Based on results of the FE analysis the new relationship of limit shear strain of the shear panel to plate slenderness parameter was proposed. The result of seismic response analysis also concluded the correlation of the structural parameters of the shear panel to the seismic responses.

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 In face of applying the limit state design method for bearing resistance to high strength frictional bolted joint, concrete definition of bearing resistance state and a rational evaluation method for bearing resistance corresponding to the definition are required. But, there is no provision of deformation property such as hole deformation in Eurocode already using the limit state design method, and the bearing limit state is not prescribed in Japan. In the past, we revealed bearing resistance based on hole deformation by tensile tests for frictional bolted joint with one bolt. In according with the test results, we carried out the same tests with a few bolts, then demonstrate relationship the bearing resistance of the overall joint and each hole deformation. Therefore, when the ratio of bolt pitch of bolt diameter p/d is more than or equal to 4.5, the bearing resistance of the over all joint is taken as the number of bolts multiplied by that resistance with one bolt.

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 Earthquake early warning systems are working to stop running trains immediately when earthquakes, that are large enough to affect the safety of railway facilities and running trains, occur. These systems have worked effectively in the past large earthquakes. On the other hand, it is expected that the performance will be improved to enhance the safety and reliability. The seismographs utilized for earthquake early warning systems have important functions to estimate the seismic parameters for issuing the warning and to discriminate seismic motion from other vibration. In this paper, we present the developed algorithms for actual use and the results of validation between the current methods and the proposed ones.

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 Reinforced concrete (RC) members covered by high-density polyethylene pipe with arc shape controller system have been firstly proposed to be applied as vibration controller or damper, which requires high deformation capacity. The arc shape controllers are set at the end of RC member to appropriately control its bending deformation in plastic hinge region. Moreover, high-density polyethylene pipes are used to cover the RC member for its durability and to confine and prevent the spalling of concrete cover efficiently. These systems can improve the deformation capacity dramatically. To evaluate the deformation characteristics of the proposed RC damper, cyclic loading tests and simulation analyses are conducted in full scale of RC dampers by varying the dimension of arc shape. In this research, it is found that the deformation capacity of the proposed RC damper is more than twice of conventional RC damper under cyclic loading. The deformation mechanisms of the proposed dampers are evaluated and discussed in this paper.

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 In this paper, influence of number of rows of bolts and plate thickness on slip resistance is discussed based on the slip resistance tests. The slip resistance tests of high strength bolted friction type joints with uncoated contact surfaces were carried out for the test specimens which have combinations of 50/75mm thickness plates and 3/8/12 rows of bolts. As a result of these tests, it was observed that all the specimens had slip coefficients over 0.4 which is specified in the current deign code, Japanese Specification for Highway Bridges, and it is found that the slip resistance of the 12-row-specimens decreased approximately 3% compared with 8-row-specimens.

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 In seismic design, it is important to consider uncertainties in structural response. Although experimental data of material variations has been accumulated, there is very few data of nonlinear dynamic structural response to be able to evaluate quantitatively. This paper presents 3D shake table experiments on 16 middle-scale reinforced concrete bridge column type specimens at E-Defense. Simultaneous excitation of specimens on the same shake table can guarantee the same dynamic inputs. As the results, the COV of the displacement response of the first nonlinear excitation was found to be not so large because the response on the skeleton curve was much more stable than the response in the hysteresis loops. This result can be the evidence to support validity of the current displacement-based seismic design.

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 Many fatigue cracks are observed at welded toe between steel deck plate and vertical stiffener. In this study, to compare the effects of fatigue life extension of three repair methods for crack initiated at the welded toe, bending fatigue tests were carried out. The repair methods are crack removal method by disk grinder, ICR treatment and stop hole. As the results of fatigue tests, it was clear that crack removal method by disk grinder and ICR treatment could prevent crack re-initiation. On the other hand, in case of stop hole, fatigue crack was re-initiated at stop-hole edge under low stress range, if stop-hole edge was not treated by disk grinder. Furthermore, the effect of fatigue life extension by the repair methods cold be evaluated qualitatively by FE analysis.

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 Fatigue cracking in the rib-to-deck weld of the orthotropic steel deck system has been one of the most serious problems in recent years. In Japan, a closed section of U shaped longitudinal rib plate has been employed. Usually, a fatigue crack is initiated at the root of the weld. The fatigue crack cannot be detected by the visual inspection. A phased array ultrasonic testing system was newly developed especially focusing on the nondestructive evaluation for the fatigue cracks in the rib-to-deck weld. In the system, two types of data acquisition process were employed. One was the conventional steering and focusing method. The acquired wave data were superposed in the flaw detector (superposition in hardware). The other was the full matrix capture. Wave forms were acquired one element by one element, and superposed in the computer (superposition in software). Specimen with an artificial slit made by electrical discharge machining was used for the validation. Fatigue test was carried out. The specimen was failed after more than 1 million cycles. Beach marking showed the propagation of the fatigue crack. Both data acquisition methods showed good agreement with the actual crack height. Even the full matrix capture showed better agreement. The minimum crack height was estimated about 2 mm.

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 There are some problems in the vehicles overturning due to strong crosswinds. For road managers who decide a traffic regulation, designing an algorithm to give a warning signal in advance is an important issue. The purpose of this research is to obtain aerodynamic knowledge and wind condition when running vehicles overturn. In this paper, the following items are discussed: (1) To derive two components of static aerodynamic force: aerodynamic force coefficients in a boundary layer and gust response factor taking into account a probability of up-crossing the overturning wind speed level. (2) To obtain an on-site wind condition when overturning occurs by solving the equation of angular motion. (3) To examine the running vehicles aerodynamic characteristics caused by sudden strong crosswind using wind tunnel tests and onsite observation tests. As a result, the aerodynamic force acting on running vehicles can be estimated by static force. Finally, a risk curve to indicate critical on-site average wind speed and wind direction is to be obtained. It is also investigated whether this method is applicable to strong wind area.

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 High frequency component predominant ground motions were observed at Tsukidate, Miyagi during the 2011 Great East Japan Earthquake. The mechanism of seismic response and resistance of bridge column with rubber bearing supports which is concerned to resonate in high order vibration mode due to the high frequency component predominant ground motion was studied by the shaking table test using the quarter sized model. The result of this test showed that the reinforced concrete pier itself shaked in the high frequency, in the same way as the dynamic analysis. Meanwhile, the high frequency vibration of the reinforced concrete pier increased its shear strength by the strain rate effect and the deep beam effect. It was also estimated from the study of the shake table test results that the reinforced concrete bridge column with the flexural failure type was unlikely to be damaged, since the period of the motion became longer and the seismic response of the column was less likely to be amplified, if the column base section reached flexural-yielded by the vibration of the column itself.

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 In this study, the hysteretic behavior of High Damping Rubber (HDR) bearings under bi-directional loading condition is discussed and a new numerical model is proposed for accurate seismic response simulation of isolated bridges. The difference of hysteretic behavior of HDR under horizontal uni- and bi-directional loading was analyzed based on results of loading tests. Representative simple numerical models, such as the orthogonal combination of bi-linear hysteretic models, Multiple Shearing Spring (MSS) model and the Park-Wen model were found having significant different in simulating the tests results. As a consequence of discussion on the source of the difference of numerical and test results, a modified version of Park-Wen model is developed and proposed. The modified Park-Wen model allows effective representation of effect of the bi-directional shear strain components to the increase of hysteretic energy dissipation at high strain levels, with a minimal number of model parameters. Validity of the modified Park-Wen model is shown by comparison with bi-directional static loading test results, as well as pseudo-dynamic tests of high-damping rubber bearings.

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 On the orthotropic steel deck, thickness reduction of the deck plate sometimes occur due to rainwater from pavement crack and salt supplied by deicing agent. The one-sided plate bonding method, that can be done in a short time and do not affect traffic flow, for repairing the thickness reduction has been studied by bending tests and FE-analysis.
 In this paper, the effect of the one side patch plate technique is confirmed by the static and fatigue wheel loading tests and FE-analysis, using the real-sized specimen with an introduced thickness reduction which simulates corroded damage. The stress distribution due to the different size or position of the thickness reduction area were also examined. In addition, it is confirmed that the required thickness of patch plates resulting from real-sized tests and analysis have conformed with the thickness design method for the corroded plate proposed in the previous study.

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 This study experimentally investigates the ultimate strength and load-displacement relationship of steel columns with rectangular hollow cross section. Firstly, compression tests using short column specimens are carried out to obtain their load carrying capacity. Secondly, monotonic and cyclic loading tests using long column specimens are carried to reveal the effects of local and member buckling and loading patterns on the ultimate strength and load-displacement relationship. It is concluded that the loading pattern does not influences on the load carrying capacity of the column and the load carrying capacity of a column without local buckling can be figured out through frame structure analysis.

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 We have installed a high-density monitoring system for the seismic motions of ground and viaducts, in order to understand dynamic behaviors of the viaducts during earthquake ground motions. It is also expected that the observed data is applied to verify numerical techniques for seismic response analyses. A new data logger is developed for this system to record more accurate motions than conventional loggers. The new logger can provide dynamic range of more than 120dB with 24-bit resolution and sampling rate of 200 samples per second. Sensors of the system are set under and on the ground, and on the structures. We introduce the details of the system and discuss some preliminary results of analysis in this manuscript: basic parameters for dynamic properties and difference of motions between neighbor structures, which play very important roles for the safety of moving trains.

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 This paper describes an experimental study on video image based analysis by using digital image correlation method so as to acquire the dynamic behavior of concrete structures. In the laboratory and in the field test, we used video images recorded by a high-frame-rate video camera and then calculated the time histories of in-plane displacement distribution of the images to measure the behavior of concrete structures, such as the change in deflection and crack. As a result of the cyclic loading test of a damaged T-shaped concrete beam, it was successfully proven that our method provides reasonable dynamic deflection and crack opening displacement. In the field traffic loading test, a concrete bridge deck was measured from the ground. It was found that the in-plane displacement of images is affected by deflection due to live loading, thus we estimated deflection by video images recorded under the deck. In fact, the estimated deflection was satisfactorily shown to correspond to the laser displacement sensor. Moreover, we demonstrated the extraction of the maximum crack opening displacement by subtracting the estimated deflection.

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 When a high-speed train moves into a tunnel, a compression wave forms in the tunnel and propagates towards the tunnel exit. A part of the compression wave is diverged from the main tunnel route to the side branch tunnel, and then a micro-pressure wave, a low frequency noise, is discharged from the portal of the branch end. To reduce a micro-pressure wave, we propose a porous absorber attached to the wall of a wind path in the side branch. The effect of the absorber is studied with a scale-model experiment, where a model train moves into a model tunnel with a side branch. The result shows that a micro-pressure wave is reduced by up to half, and that the reduction increases with the area of the porous wall of the absorber. Then, a porous absorber is constructed in the test railway line in Yamanashi, and the field measurement result also shows the reduction of a micro-pressure wave by the absorber.

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