To estimate corrosion environment for weathering steel bridge, we investigated chemistry of salt and corrosion level on girders of the bridges in Shimane. Quantities of Na⁺ and Cl^- on girders are positively correlated with rust thickness and corrosion level, indicating that these quantities are proxies for corrosion environment. Girders with Na⁺ and Cl^- volumes higher than 5 mg/m²/y show thicker rust than 400 μm and worse corrosion feature, suggesting weathering steel should not be used under such environment. Relative to web, lower flange is enriched in Na⁺ and Cl^-, and shows worse corrosion feature. Accumulating salt on web potentially migrates to lower flange due to dew, and corrosion on flange probably advances.

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The paper presents characteristics and challenges of Japanese maintenance technology through investigation of historical development and comparison with U.S. It is shown that Japanese development is motivated by the status of infrastructure stock of each age, i.e., A) functional obsolescence at Taisho era, B) deterioration at WWII period, and C) initial defect at post war economic growth period. In comparison to U.S., Japanese development is more focused to technological aspects, while importance of resource allocation is stressed in U.S. from social point of view. In both countries, technological development is highly influenced by implementation of systematic inspection and information management

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The relationship between initial displacement and converged one, which has been used to judge the convergence and the time for execution of tunnel supports, is conventionally evaluated to be one linear line. Though, the actual situation of convergence during tunneling is influenced by the bench length. In order to construct tunnel more safely and rationally, tunnel convergence should be predicted accurately and be controlled by tunneling method. In this paper, the effects of tunneling methods to the relationship between initial displacement and converged one are analysed based on the convergence data, measured in the sqeezing rock tunnel. Also, qualitative evaluation using 3D numerical analysis is carried out.

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Feasibility study of the longer continuous composite two I-girder bridges was done utilizing the Bridge High performance Steels (BHS) in combination with the conventional steels. First, allowable unit stress and minimum plate thickness of steel girders were formulated. Then, the difference between the BHS and the conventional steels on local buckling of flanges and on lateral buckling of the girders was clarified and structural characteristics and cost effectiveness were investigated based on the outline design of actual bridges. Finally, problems of the longer continuous composite two I-girder bridges using the BHS were examined and necessary means against these problems were proposed.

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Recently, increasing amounts of reinforcement are used in reinforced concrete rigid-frame railway viaducts in order to build them earthquake resistant. Especially, joints of columns consisting of single piles are congested with bars, and thus it is difficult to assemble bars and place concrete.
The authors devised a structure in which not the bars of the pile but a steel square pipe embedded to the head butts is fixed to the joints. This study investigated the load carrying mechanisms and the deformation performance of the structure from the results of alternating loading tests, and showed the effectiveness of the structure.

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The design model for load acting on the segment during tunnelling in a shield tunnel is not prescribed clearly. However, it becomes necessary to build the design model because it is very likely that load during tunnelling becomes critical in a large depth tunnel where increase of a plan is anticipated.
Therefore we examined behavior and the stress state of the segment by analyzing measurement of the segment during tunnelling in a large depth tunnel and three-dimensional FEM which simulated a construction step. Based on these results, we presume damage factors of the segment during tunneling and show the opinion for the design for load acting on the segment during tunneling.

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Masonry walls made with ashlars are often applicable as a protection work for cut or embankment slopes along railways. However, adequate methods to reinforce the masonry walls have not carried out, because the behavior of masonry wall during the earthquake has not been clear. Therefore, we devised quakeproof reinforcement methods taking account of a deformation mechanism of the masonry wall during the earthquake, and clarified their effectiveness by tests using scale models. In addition, we investigated the method considered about the real works, in consequence we concluded that devised reinforcements are applicable by simple methods.

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The Philippines is essentially a typhoon-prone area which poses a threat to the structural integrity of wind turbines. Due to this scenario, the authors classified the country’s wind climate according to the IEC classes. The generalized extreme value distribution was used to model the extreme wind speeds from each of the fifty stations. Areas exceeding the IEC class I 50-year return wind speeds were classified as Class 1a.
Subsequently the probability of buckling failure of a wind turbine was analyzed. The analysis shows that there is a need to increase the mean of the tower buckling resistance by a factor of 1.02 to 1.74 to mitigate buckling failure due to typhoons.

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