Jacket structures have many features as follows: a few foundation piles and reduction of site construction period caused by extremely high horizontal rigidity, moreover high manufacturing quality. In the construction of Tokyo International Airport Re-expansion Project, jacket substructures are applied to pile-elevated structures and connecting taxiways. This paper describes structural plan of marine bridges for airplanes, moreover applicability of jackets for substructures to marine bridges for airplanes.

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Optimum designs of 2-span continuous I-girder bridges are carried out. This design mainly aims to reduce the bridge weight. The global solution is figured out by beam theory approach; then, the design is optimized by FEM from the global solution. The design method is based on LRFD, and the design applies the newly developed material “SBHS”. The optimum calculation shows drastic reduction of steel weight.

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In this study, in order to clear the mechanical behavior of panel point of steel truss bridges using high strength bolted frictional joints, tensile loading experiment is carried out at first. Secondly, in order to make more detail clarification of the mechanical behavior and to examine the effective width of the gusset plate, finite element analysis has been executed by using the model which has same configuration of the specimen. From the results of this experiment and analysis, the collapse behavior of panel points of steel truss bridges is discussed and applicable evaluation methods of the load carrying capacity for yielding of such panel points are proposed.

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In this study, cyclic loading tests were conducted to clarify the extremely low cycle fatigue crack (ductile crack) initiation and final failure mode in thick-walled steel beam-column connections with different conditions of the finished weld bead. Three test specimens are manufactured with the weld bead by toe burr grinding, R finishing and as-weld, respectively. Discussions of ductile crack initiation and progression, local strain and load-displacement relation are made to investigate the effect of the condition of the finished weld bead.

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The present study discussed fatigue performance on a column type transformer and pole top-type pillar subjected to wind load. For this purpose, a wind response observation, a finite element analysis, a fatigue experiment and estimation of cumulative fatigue damage were conducted. Furthermore, performance on a specimen whose fatigue performance was improved by changing space of an upper open area and smoothing weld toe was discussed. Consequently, cumulative fatigue damage of the well-performed pillar was about one-tenth of the original configuration.

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