Precooling of concrete to reduce placing temperature is used as an efficient countermeasure for thermal cracks in mass concrete. Precooling has been used from the 1950's in Japanese concrete dams, but use of precooling in concrete structures except dams began in the 1970's. Firstly, this report was conducted to systematize the precooling based on past research results. Secondly, this report summarizes past research results on efficiency of precooling, and provides the summary of main precooling methods. Subsequently this report describes the summary of actual results of precooling in Japan.

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Splicing of reinforcing bars is indispensable in reinforcing technology. Lap splices and gas pressure-welded splices were common in reinforced concrete construction, but recently many kinds of mechanical splices have been developed to joint high strength and large-diameter bars or pre-cast concrete members. In this paper many kinds of splices are classified, and then the characteristics of the splices are described. Besides is summarized currently available information about the study on structural members with splices.

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Aomori Bay Bridge is a coastal road bridge for the purpose of integrating port facilities. Its main portion is a three-span continuous prestressed concrete cable-stayed bridge. The cable-stayed bridge measures 240 m in main span and 498 m in total length, and is one of the largest bridges of this type in Japan. This bridge is characterized by inverted Y-shaped pylons and single cable system. Stay cables are all erected in site, and for its covering tubes. FRP (fiber rein-forced plastics) tubes are adopted. In design and construction of superstructure in this cable-stayed bridge, this paper reports construction of main girder and stay cables, and construction control.

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The Rissyo Kosei-Kai Kobe Branch Church was built as a seminary of Kansai Area. The Building has a shape designed for stable and solemn impression to be worthy of a religious building. The structural design of the building is reinforced concrete and steel reinforced concrete. Especially, the main structure is consist of four core parts of the corner and long span beams (about 30 meter span length) made by steel reinforced concrete. Super-durable Concrete is applied to the building for long term use and worthy of a social inheritance. It was built carefully about mix pro-portion, setting and curing to improve durability.

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This spring, Tokyo opened a new city hall in the Shinjuku district of Tokyo. This three-building complex, consisting of the Tokyo Metropolitan Government No. 1 Building, No. 2 Building and the Assembly Hall, is spread over three city blocks. The most prominent, 243 m-high Tokyo Metropolitan Government No. 1 Building, is the tallest structure in Japan. Kenzo Tange Associates opted for a Super-frame Structure and applied lightweight concrete to slabs of the structure. In Japan, up to that time, it was impossible to directly transport concrete from the ground to a more than 200 m-high place by concrete pump. Engineers and researchers concerned with this construction were determined to meet the challenge of transporting concrete directly to the highest floor of the Tokyo Metropolitan Government, 243 m-high. By the effort of these engineers and researchers and by the development of a new concrete pumping machine, the transport and placing of concrete from the ground up to the 243 m-high place was accomplished. The construction of Tokyo Metropolitan Government was completed smoothly due to these efforts and technical developments.

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[in Japanese]

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