Masonry structures with clay and stone units were constructed under intensional policy of strengthening the economical and military power of Japan in the Meiji era. However, this type of building structures has not been used, since the Kanto earthquake disaster destroyed unreinforced clay masonry buildings. Recently, the development of high aseismic masonry structures has been requested, because the high durability and appearance of masonry structures has been highly estimated as with indispensable merits for buildings. The RM structure introduced in this report, is a kind of newly developed reinforced masonry structures in order to solve the seismic problems under a cooperative research program between U.S. and Japan. The draft guidelines to structural design and construction methods of medium rise RM structures are briefly explained.

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In recent years, as reinforced concrete structures become taller and larger, high strength reinforcing steel bars designated as SD 50 has been widely used, and the relevant design and construction methods have been developed. This report is focused on whether gas pressure welding is applicable to both blast furnace and electric furnace high strength reinforcing steel bars. In order to investigate its availability first the optimized welding condition was determined, and then the joint strength test was carried out. The test results showed that the welded joint strengths for both blast and electric furnace reinforcing bars meet the values specified in JIS, and that gas pressure welding is applicable to SD 50 reinforcing steel bars.

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The building presented here is the very first building of RM structure, design and construction of which is described. RM is abribiation of reinforced masonry (of new type) which was brought from the U.S.-Japan coordinated research program of masonry structures for five years. In addition to high rigidity, high ductility is the characteristic of RM structure, which resuts in excellent earthquake resistance. After laid and reinforced with steel bars, RM units are fully grouted to form a monolithic structure. This construction method is considered excellent from any view points of arbitrariness in design, economy and construction practice. It is expected to be employed for collective residence, school and any type of buildings successfully.

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We, at Shinanogawa construction work office of East Japan Railway Company, are constructing a new hydro-power plant by the working on. This report says the Extruded Concrete Lining Method (E.C.L. Method) which used for that. It contains, at first, the outline of Shinanogawa electric-power plant projects and E..C.L. Method. Section “Design of Tunnel”, it presents data which calculated on Finite Element Method (F.E.M.). Concrete lining of E.C.L. tunnel have to unprecedented qualities, keeping fluidity a fixed time, displaying strength in early stage, for air pressured concreting with long pipes. So this report says selectively about development conditions, indoor experiment and the qualities of actual used concrete, and it refers to concreting test of concrete included fiber. For this method is one of rapid driving of tunnel, report makes speed of this method clear with the actual stage of work.

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[in Japanese]

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