This paper presents an introduction of some demanding topics of study for the planning, design and technical development of the guideway structures for JR's superconductive magnetic levitated railway system. These include the method of combining track and infra-structures to maintain the position of the elements to minimize long-wave track irregularity (beam-type guideway system for side-wall levitation), the dynamic design of structures for ultrahigh-speed vehicles, the evaluation of riding comfort and running stability through dynamic interaction analysis between vehicle and structure, the study of the deformation and deflection of long-span bridges to select adequate types, and low or non-magnetic guideway structures.

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Recently, structural design and construction methods of highrise reinforced concrete building using high strength concrete have been developed by leading private construction companies, and research and development related to making high strength concrete for reinforced concrete buildings has been actively promoted. Ministry of construction promoted the five years project entitled “Development of Advanced Reinforced Concrete Buildings Using High-Strength Concrete and Reinforcement (New RC)”, which aims to put super-high strength concrete practical use for reinforced concrete buildings. This report describes the trends of research and development on high strength concrete for reinforced concrete buildings.

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This report describes the design and construction of Shiraya Bridge, the two-span prestressed concrete cable stayed bridge constructed over the Ohtaki Dam reservoir. This bridge is characterized by having a high pier and the asymmetrical two-span arrangement, and therefore the construction control during the balanced cantilever erection was important. For the cable system the Freyssinet anchor system was applied with stay cables erected on site and newly developed FRP (Fiber Reinforced Plastics) covering tubes, that can be colored optionally.

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This building was constructed with the “Composite Layered Construction System”. In this system, composite beams of structural steel in the middle and reinforced concrete at both ends, and centrifugal precast concrete columns were manufactured in a factory, and those members were connected by cast-in-place concrete. High strength concrete of 600 kgf/cm² was used as the joint concrete at some joint locations. By the use of the composite layered construction system, we succeeded in the saving of time and labour in the construction of an office building of long span, while maintaining the advantage of low cost of reinforced concrete construction. From this application, we have obtained know-how of the construction of high strength cast-in-place concrete. This paper describes the outline of the composite layered construction system, and reports the construction method and quality control of the high strength concrete.

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