According to Japanese specifications for highway bridges, the frictional bolted connection has had to carry out to be safe for the major slip or the member yield. On the other hand, other specifications based on the Limit State Design method permit the connection to design for after major slip. Therefore, it is desirable that the after major slip design is also possible in Japan to convert the Allowable Stress Design to the Limit State Design method. However, the present Japanese bearing strength of bolted connection is lower than foreign. In addition, the initial residual axial force may be able to tolerate greater bearing stress than non tightening connection. Therefore, we carried out the test of frictional bolted connections to measure the limit-bearing-stress based on hole deformation and reveal mechanical behavior of them. Furthermore, we tried the quantitative evaluation of the effect of frictional force remaining after the major slip.

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 The long-period ground motion class of Japan Meteorological Agency (JMA), which is divided into four classes depending on the maximum velocity response spectrum, is tried for the long-period ground motion, though the seismic intensity scale of ten classes based on the instrumental seismic intensity is used. The present study proposes the long-period ground motion class by using a long-period seismic intensity level to have an intermediate characteristic of the velocity and the displacement. The long-period seismic intensity level based on the seismic intensity level is obtained for the maximum value to have the correlation between the long-period ground motion class of JMA. Not only a design long-period ground motion waveform but also observed seismic waves are used for comparison with the long-period seismic intensity level and various seismic intensity levels, maximum velocity response spectrum.

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 This paper is concerned with experimental tests on the ultimate shear strength of steel plate girders composed by corroded web plates with different corrosion patterns. The experimental investigation, performed through three points bending tests on the girder models with the full scale original forms of corroded web plates, have been carried out in order to asses the influence of different corrosion patterns on the strength. The influence on the shear buckling of the corrosion patterns is also discussed together with the failure patterns observed during tests.

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 The 2011 off the Pacific coast of Tohoku Earthquake with the moment magnitude of 9.0 caused severe damage to lifeline systems. In Sendai City, Miyagi Prefecture, where is the most populated city in Tohoku district, the suspension of water supply was occurred at approximately 230, 000 family units. This study investigates the relationship between the damage ratio of water distribution pipeline and ground motion intensity in Sendai City during the earthquake. The damage ratios in the developed hilly areas are compared with those in lowland considering the ground motion intensity. Based on the results, the use of correction coefficient for the developed hilly area is proposed to predict the number of pipe breaks of water distribution pipeline.

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 Japanese specifications of railings require minimization of the cost, landscape-friendly appearance and continuous flow in the road user's as well as the four basic performances. In this paper the optimum design method of new bridge railings using the genetic algorithm for the multi-purpose functions has been developed to obtain the Pareto solutions. They were confirmed the availability comparing with the existing railings satisfied all requirements of the specifications. The static and collision analyses of vehicle and railing finally certificated the efficiency and safety of the developed design method.

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 In recent years, for making bolted connections convenient and compact, higher bolt axial force of the high-strength bolt is required. In this background, a development project of 1,800 N/mm² class ultra-strength bolts was launched by NIMS (National Institute of Materials Science). The key point of this project is prevention from the delayed fracture of the bolt, which the tensile strength of the bolt is over 1,000 N/mm². The delayed fracture is easy to happen in a high stress and a large plastic strain location. Therefore, in this paper a new thread form (called NEW thread form) has been developed for reducing the high stress and the large plastic strain on the location of thread roots. Finite element analysis was executed to compare reduction of the stress and the plastic strain on the thread roots between NEW thread form and usual thread form (JIS thread form/SHTB thread form). Finally, performance verification tests has been done for NEW thread form bolts and JIS thread form bolts made from a developed material (tensile strength 1,800 N/mm²) by NIMS.

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 This study aims at establishing the evaluation method of optimum earthquake resistant level of quay walls considering seismic hazard. The proposed method evaluates optimum earthquake resistant level of quay walls using optimization algorithm. Both recovery cost and economical loss cost according to earthquake resistant level of quay walls are taken into account considering all the wharves in the port of interest. Examples of application of the proposed method for three ports are shown.

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 It is known that stationary human occupants act as dynamic mass-spring-damper systems and can change modal properties of civil engineering structures. However, there is a lack of information on the properties of such structures occupied by stationary people. The purpose of this study is to extend the limited knowledge available. A full scale measurement is carried out to investigate the influence of stationary people on a slender and lightly footbridge with center span length of 33m. Modal properties (frequency and damping) were estimated from the damped free vibration. Complex eigenvalue calculation is also conducted using two degree of freedom ISO5982:1981 human model. Based on experimental and analytical results, it is revealed that the structural damping of the footbridge increases according to the increase of number of stationary people on the center span of the bridge due to the dynamic interaction.

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 When we decompose the earthquake motion phase into a linear delay part and a fluctuation part, the latter part of phase has a self-similar characteristic because of the self-similar nature of inhomogeneous medium in which earthquake wave propagates. It means that the macro scale inhomogeneous structure in the medium has a similarity with the micro scale one. Therefore we can assume that the scattering characteristic of propagating wave in high frequency range has a similarity with that of low frequency range. This means that the phase shift due to wave scattering in high frequency range has a kind of similarity with that of low frequency range. Based on this similarity hypothesis we derived mathematically the basic stochastic characteristics of phase difference. We showed that the simplest and most practical stochastic process satisfying these results could be expressed by the fractional Brownian motion (fBm) process. Assuming a pulse like wave propagating in the inhomogeneous medium and considering the uncertainty of scattering nature which is transformed into the uncertainty of phase modeled by fBm process, we found that the uncertainty of earthquake motion phase expressed by this process was evaluated by a reduction of earthquake motion amplitude. Moreover using a simple fault rupture process expressed by a train of impulses we demonstrated the effect of phase uncertainty caused by inhomogeneity of wave propagation medium on the amplitude reduction of time history of earthquake motion.

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 Cast steels were used in bearing of steel bridges. It was considered that the quality of these cast steels has been remarkably improved. However, the statistical characteristics or the chemical compositions of the material are not clarified. In this paper, I have investigated cast steels on the basis of the mill sheet in order to clarify their quality. Investigated items were tensile strength, yield strength, Charpy-absorbed-energy, elongation and yield ratio, and these mechanical properties were shown. Then, investigated component were Carbon, Silicon, Manganese, Phosphors, Sulfur, Copper, Chrome, Nickel and Ceq (Carbon equivalent), and these results were shown. We also showed the quality of these cast steels, comparing with the conventional steel data.

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 Shear connectors in steel-concrete composite structures generally subject not only to shear force but also normal force. Two models for representing shear strength of L-shaped steel shear connector under shear and normal forces are proposed. First model is that shear strength comes function of the compressive strut angle but its applicable range is limited. The idea that effect of normal forces is added to shear strength without normal forces is used in the second model. The equation form in this model shows continuity of concrete compressive strut angle. It is confirmed that an exponential equation similar for headed studs can be applied for shear force-slip relationship of shear connectors.

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 The purpose of this study is to propose the human walking and running force by using FFT power spectrum from the experimental acceleration data of the human body. An experiment on human walking and running is carried out on a stationary floor. Effectiveness of the proposed method based on body response spectrum by FFT analysis is discussed compared with the existing walking and running forces for vertical component determined by force transducers. It was found that there is a slight difference between males and females when walking and running on a stationary floor. Based on these results, it is confirmed that the present method might be an effective means to identify the walking and running vertical forces for the dynamic analysis of pedestrian bridges with sufficient accuracy and less complexity.

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