In this study, we proposed a method to evaluate a site spectrum using amplification factors for peak ground acceleration and JMA seismic intensity, H/V spectrum of microtremor at local government observation sites where seismic waveform records were not stored. Firstly, the amplification factors and site spectra of acceleration response spectra at JMA, K-NET, KiK-net observation sites in the Chubu region were evaluated by a regression analysis. The amplification factors and site spectra have a good correlation at less than one second of period. In order to improve the evaluation to site spectra at more than one second of period, we used a function approximated by the H/V spectra as a parameter of the site spectra. The site spectra by a regression analysis using amplification factors and the approximated function were evaluated. The precision of evaluation at more than one second of period was improved.

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 Recently in Japan, fatigue cracks which initiated from the root of welding joint between deck plate and U-shaped rib and propagated toward the upper surface of deck plate in orthotropic steel decks have been reported. In this study, to evaluate fatigue life of welding joint for these root cracks, the reference strain was defined. First, the position of the reference strain was discussed. Second, the relationship between the reference strain and stress of root was investigated by analytical method, based on the results of wheel trucking tests with actual size specimens and filed stress measurements. Finally, fatigue life was evaluated and was clarified the quantitative effect that thicker deck plate influenced to fatigue durability of welding joints.

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 This paper presents a method for the evaluation of the rock capturing performance of a grid-shaped steel check dam. The evaluation method is based on the probabilistic estimation of the number of rocks passing through the grid; this number follows a random geometric dist ribution. In order to predict the probability of the plugging of the grid by the rocks, the plugging phenomena were defined on the basis of the geometrical combinations and arrangement of rocks; the probabilities of these plugging phenomena were simulated through the Monte Carlo simulation method. The coefficient used in the proposed method is fit to the experimental results. Finally, the capturing performance and robust ness of some actual check dams were evaluated using the proposed method.

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 For the purpose of clarifying the fatigue strength of a main girder web connected to a lateral girder flange which is repaired by bolting stop-hole method with attached steel plates, fatigue tests have been performed on girder specimens. In addition, fatigue tests have been also carried out on small specimens modeling the repaired parts in order to investigate the fatigue crack origins of the repaired parts. Furthermore, the effect of the repair method has been compared with those of stop-hole method and/or bolting stop-hole method though the fatigue tests. It has been confirmed that the fatigue strength of repairedparts is considerably high and almost equal to that of friction type of high strength bolted connections.

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 In this study, the scale-down RC storage tank models 3D shell were tested under reversed cyclic loads to clarify the load-carrying mechanisms of the underground LNG storage tank.
 As a result, when the sidewall of the tank is shear-deformed, overall load-carrying capacity of the structure is controlled mainly by the capacity of the web side parallel to the displacement direction, and the decrease in load-carrying capacity is caused by the localization of strains according to the compression failure in web concrete. Moreover, 3D nonlinear FEM analyses could be reproduce accurately the relationship of load ver sus deformation angle obtained by the tests, and a response value of compressive strain gave good agreement with the deformation angel of maximum load.

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 Empirical relationships are evaluated to predict site amplification factors due to deep underground structure beneath engineering bedrock based on the characteristics of strong motion data which are observed in Kanto plain. As the result of estimation regarding the characteristics of strong motion data, amplification factors almost agree with the theoreti cal amplification factors estimated from the deep underground structure by Yamada (2000) in the case of coincident source and site basin locations (CBL). On the contrary, amplification is much larger than th e theoretical one in case of distinct source and site basin locations (DBL). For the difference of charact eristics between CBL and DBL, it's the reason that the mechanisms of seismic basin response de pend on the location of earthquake sources.
 The relationship between the corrected factor and the basin depth is compared with the apparent incident angle of seismic motion to include the effect of the locations of the sources. The corrected factor is defined as the ratio of the amplification of the observation records divided by the theoretical amplification. The variation between the amplificati on factors and basin depth is decreased by including apparent incident angle. The equations for estimating the amplification factors which are considered from the amplification factor at the vertical incident, the basin depth and the apparent incident angle. For the validation of the evaluation, the equations are applied to Osaka Plain. The result shows that ground motion spectrums which are estimated by this study almost agree with the observed ones.

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 As trains are getting faster rapidly, it is necessary to adjust RC railroad viaducts and their components for coping with structure noise. In this study, th e authors conducted a train running test to grasp the vibration characteristics of the slabs of actual RC beam viaducts and RC rigid frame viaducts, in order to clarify the vibration characteristics of the components of RC railroad viaducts, which are necessary for evaluating and predicting structure noise. Then, it was found empirically that an RC beam viaduct has a vibration mode of the intermediate slab around 130Hz, and this mode becomes remarkable when a train passes. It was also revealed that in the case of an RC rigid frame viaduct, several vibration modes of the intermediate slab are excited in the frequency range over 50Hz and the second-order mode of the middle slab becomes significant around 60Hz when a train passes.

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 The quasi-dynamic equivalent linear analysis method has been used in a current design of in-ground LNG tanks. The dynamic nonlinear analysis method is expected to contribute to more rational design.
 3D nonlinear seismic response analysis was conducted to verify the applicability of the analysis method to the tank-soil coupled system and to evaluate the seismic performance of in-ground LNG tanks under level 2 earthquakes. The recorded responses were simulated and the results from 3D dynamic analysis coincided with the observed records. It was confirmed that the existing in-ground LNG tank has sufficient safety against level 2 earthquakes and this means more rational design is applicable to the in-ground LNG tank.

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 Fatigue cracks have been reported in the column and beam connection of steel trestle bents of highway bridges. The previous studies have showed that a prism shaped incomplete penetration in the intersection of three welding lines reduced the fatigue life. When the weld groove finishing and/or welding process was inappropriate, those incomplete penetrations were left. This study is aimed at detecting the incomplete penetration by the ultrasonic nondestructive technique. There are three patterns of the plate assembly applied in Japan. This study focuses on two of them. Two specimens were made, considering the details of the connections. This study also utilizes the information of plate assembly, because the orientation and size of the incomplete penetration depends on the plate assembly. Under the assumption that an incomplete penetration consists of five surfaces, ultrasonic test was carried out. It was possible to obtain some echoes from the incomplete penetrations. Based on the test data, the image of the incomplete penetrations could be reconstructed.

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 Although introduction of vibration control systems for bridges have advantages in terms of both seismic performance and construction cost, seismic design method of the bridges utilizing dampers is still developing. The purpose of this study is to promote the design method of bridges utilizing dampers. This paper describes the result of shaking table tests of bridge models with friction slip dampers. Followings are found. (1) It was observed the dampers and the pier models exhibiting nonlinear behavior resisted to the earthquake action in cooperation. (2) It is found that the friction slip damper is effective to reduce the response displacement. (3) The contribution of the damper to the each level earthquake is determined. Furthermore, numerical modeling of the damper is developed through the dynamic analysis.

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 The large scale sliding seismic isolation bearing was employed on Tokyo Gate Bridge. The sliding isolation bearing consists of two supporting members: a horizontal buffer which resists horizontal reaction forces ; and a vertical bearing which bears vertical reaction forces and functions to attenuate energy via friction resistance of the sliding surface. Accordingly, a friction coefficient on the sliding surface is an important factor in designing the Bridge. In the past researches, it has been known that a friction coefficient varies depending on a surface pressure and speed of displacement. In this paper, we conducted a repeated loading test to study mechanical characteristics such as contact pressure dependence and velocity dependence of a friction coefficient in a sliding surface. We examined that, by calculating the dynamic response, how this factor affects the earthquake response of this bridge, and confirmed that the employed the large scale sliding bearing for seismic isolation reduces the movement of the bridge within the allowance range defined on the basis of the ground motion.

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 This paper describes experimental results on cracking behavior under hogging bending moment and flexure strength under sagging bending moment of a composite girder with the newly developed hybrid slab. The slab has a bottom plate, longitudinal ribs welded to the bottom plate, laying bar studs inserted into the ribs and reinforcing bars longitudinally and transversely installed on the top of the ribs. Under hogging bending moment, it was shown that produced crack width was considerable small compared to that reported in other type of hybrid slabs. Under sagging bending moment, the obtained ultimate flexure strength was a little bit smaller than plastic moment. However, taking into account of ductility condition (concrete crushing before reaching plastic moment), the obtained strength can be predicted with good accuracy.

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 The purpose of this study is to propose the simplified method to identify human walking force by using FFT power spectrum from the experimental acceleration data of the human body. An experiment on human walking is carried out on a stationary surface. Effectiveness of the proposed method is discussed for the measured acceleration data of the human body compared with the existing walking forces for both vertical and lateral component. It is pointed out that a little difference between men and women occur through the human walking on a stationary floor. These results also showed that the present method could identify the walking vertical and lateral forces with sufficient accuracy and less complexity.

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 In continuous composite steel-concrete structures, cracking of the concrete slab in the hogging moment region decreases the global stiffness of composite steel-concrete structures and reduces the effect of continuity, thus making the structural behaviour highly nonlinear even for low stress levels, so special consideration is necessary. An experimental investigation on the behaviour of steel-concrete composite beams in hogging moment region is presented in this paper. A total of four specimens were tested under point load in the mid-span. Two of the composite beams with headed studs as the shear connectors, while the other two specimens are using Perfo-Bond Strips (PBLs) as the connection devices between the steel girder and the concrete slab. Ultimate load bearing capacity of composite sections in negative moment region was calculated and compared with experimental values. Crack formation, crack widths development process and strain distribution of the composite section before and after cracking were observed and presented in this study. Interface slip distribution was also given. Research results indicate that the current specifications such as AASHTO, JSCE, and EUROCODE-4 can provide appropriate values for ultimate strength of a composite girder under negative bending moment.

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 There were the following typos in the article, "Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE)) Vol.67 (2011) , No.2 pp.446-453"

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