The effect of slenderness on column capacity has become more important because of the recent trend in structures in seismic countries as Japan toward, (1) increased exploitation of higher concrete strengths in high-rise buildings, (2) new challenge in the aesthetic design of buildings and bridges, (3) development of earthquake-free frame systems from entire dependence of seismic resistance on structural walls, (4) erection of design philosophy of weak beam-strong column type frame in which stability problem of continuous columns is inherent. The aim of this paper is to give basic understanding on design method of slender columns. Comparison is made among design code requirements in various countries, regarding slender columns. Finally suggestions are made on basic research items to be considered for prospective use of slender columns in seismic countries.

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Herein are introduced the principles, characteristics, and fields of application of the various analytical methods which are in use at present or are anticipated to be in use in the future in the field of concrete engineering. Also, the analytical method for mix-proportions developed by the Cement Association, which has been the standard for use in this field, and the JCI method of chloride analysis are explained and compared with other related analytical methods. The analytical methods used for the determination of admixture and alkalis in hardened concrete, as well as typical methods of characterization which will become available in the future, are also explained.

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Our company has developed industrialized method RC structure, namely FRPC construction method, as a measure to deal with deteriorating labor shortage. It is to utilize pre-casted frame material such as column and beam etc.. The structuring method we employed this time for the construction work of western building of commercial district of western Hiroshima is so-called RPC method that is cast-in place concrete piling of the column. If the ratio of pre-casting decreases, man power efficiency will get lowered. However, depending upon the structural shape and the scale of the buildings, the method of cast-in place concrete piling works for a better result and this case would be one of the works which attained better cost merit. Where the construction site is considerably large as is the case of this project, the construction process of pile driving and the safety control requires much attention. This time, however, we employed simulation by the personal computer for controlling drilling machine, which resulted in a satisfactory manner. Under these conditions and the aftereffect, we would like to report the content and the proceeding of our work.

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A newtype of breakwater-the double cell caisson-has been developed by Ministry of Transport. The double cell breakwater has double cylindrical vertical wall, a permeable outer wall and an impermeable inner wall are fixed on a base caisson. This type of breakwater is supposed to save the total amount of the materials, so it can be economical to construct the port under severe conditions of deep sea and high wave. Before putting the new breakwater type into practical use, double cell breakwaters were constructed on a trial basis and tested in Sakai Port to see whether it would function as designed. The contents of the test are reported in this paper.

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These buildings which were planed as the symbolic tower in “Park Field Misato” are 21 storied highrise reinforced concrete condominiums in a style of twin towers. These buildings were designed in “HRC-35” system developed by Hazama Corporation. They are featured by being applied special analysis in order to be founded on soft soil ground, placed high strength concrete having a design strength of 420 kgf/cm2, used slump retentive superplasticizer and used octagonal spiral hoop reinforcement. This report describes the outline of design, construction, and quality control of these buildings.

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[in Japanese]

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