[in Japanese]

View full abstract

To investigate the strength of wooden construciton under long sustained load, wooden members and joints were tested by the authors. In this paper, the results of our experiments including that of other authors are summarized in three items described below: 1. Bending creep tests of wooden beams; 2. Shearing creep tests of wooden joints, iron and wooden dowels, nail, bolt and glued joints; 3. Bending tests of wooden trussed girders. Furthermore, on the basis of the above results, the bearing stress or bearing power of the wood or Wooden connections and the methods of calculation for wooden constructions for long sustained load are suggested.

View full abstract

1. Snow loads should be selected considering the location, the maximum snow height, its specific gravity and the conditions of its structure. 2. The maximum snow height on flat ground and its specific gravity are given in Table A.[table]3. Temporary snow load should be calculated by the product of maximum height and its specificgravity. But in localities where snow lies long, sustairned snaw load should be given, which corresponds to 70% of the temporary snow loads. 4. Snow loads combined with wind load, or earthquake load correspond to 35% of temporary snow loads, 5. Snow loads on the horizontal projection of roofs are given in Table B.[table]c.f. If snow-guards, or roof materials which interrupt snow sliding are used on the roof, loads shoud be considered otherwise. A Due to the effect of wind, snow loads will be reduced by the multiplying factors given in Table C.[table]B. Due to the effect of severe solar radiation, snow loads will be reduced by the multiplying factors given in Table D.[table]C. Less than 25% of snow loads will be reduced by heating. D. Eaves, valleys, shed roofs and other parts of roofs which'are apt to accumulate much snow, should be given larger snow load. E. Take care of unequal snow load on each side of the roof. 6. By removing the roof snow, snow load on the roof will be partially reduced. 7. Large accumulation of snow will sometimes show strong side pressure.

View full abstract

Description of recent systematical researches regarding the strength of reinforced concrete columns, covering the following chief items is given. 1. Plastic theory of columns subjected to centrical as well as eccentrical loading. 2. Buckling load. 3. Buckling load of eccentrically loaded column, the direction of unstable flexture being in and perpendicular to the plane of eccentricity. 4. Buckling load of obliquely loaded column.

View full abstract

To get the strength of wood under vibrating loads created by calamitic force such as earthquake action or wind pressure, the writer has experimented on wooden members for compressive, tensile or bending stress by giving them a repeated load, the upper limit of which increasing to the breaking point for a short time, and investigated the effects on them by the sectional cutting defects. In this paper the results are givea in comparison with the usual statical strength, and some numerical formulas are shown to express the vibrating strength in above condition. Generally speaking, the dynamical strength is lower than the statical and the decreasing grades are more remarkable in tensile breaking of fibres than in other cases. The reduction of strength by sectional cutting defects has been observed for repeated load as will as for statical one, and the tendency is also notable in tensile breaking.

View full abstract

This report gives an account of the experimental results of the New Built-up Wooden Beams designed according to the new theoretical method which was reported by the author in July 1944 Due to lack of skillfulness in the designing technique, the new built-up beam, No. 1, was not good enough. However, test results were reported in April 1949. This time the author reports on the improved design and testing results of beams which showed superior qualities-minimized deflection and small. creep-in spite of the simplicity of its construction.

View full abstract

The coefficients in Wilson's formulas of Slope Deflection Method for statical loads may, by a certain method, be modified to make them applicable to a vibrating bar, as shown by the author many years ago. In this paper, further modifications are carried out to make them applicable to bars subjected to both vibrational and axial loads.

View full abstract

In the case indoor temperature being nearly equal to outdoor, following relations are established between ratio of humidity variation-inside humidity variation open-air humidity variation h and ratio of opening area-opening area/total surface area r_a. 1. When normall draught exists,[numerical formula]with r_v, ratio of wind velocity-each day mean velocity/mean value of wind velocity in the long term. 2. In the case for small draught, h=2.27r_a^<0・51> without regard to the indoor air volume and number of openings. If the opening, is covered with a material of porosity k, k=2.27k^<0・51>r_ap^<0・51> whersin r_ap is the apparent ratio of opening area. 3. Time lag of misture transmission φ is respectively 2.2, 1.1 and 0.5 hours in response to r_a being 0.5, 1 and 2% for the opening blowed through. In the case of the opening covered with a material of porosity k, these values of φ are multiplied by 1/k.

View full abstract

Although pure cement mortar takes large shrinkages at high temperatures, and this shrinkage is not only the function of temperature, but is also a function of heating time at constand temperature.

View full abstract

As basic problems in daylight-ilumination, the measured data, the solutions, the fluctuating character etc. of outdoor daylight illumination are shown in this paper. Especially, the method of "illumination zone for each weather" in the solution of outdoor illuminations, a very simple equation for the same purpose, the Theory of cloudy-sky-radiation, and the study on the fluctuation of outdoor illuminations etc. are quite new attempts in tbe field of Illuminating Engineering.

View full abstract

[in Japanese]

View full abstract

Especially in the case of railway stations for high speed city railways, the meaning of station accommodation must be the passage between train and streets because passengers on their way to office or home flow there as a mass in rush hours. So these stations must be designed based on the knowledge of the character of mass flow. The charac ter of passenger's mass flow will be cleared by speed and density with which these passengers walk as a mass. From this standpoint, the author tried to find out the necessary width or number of platforms, shairways, passage and wicket gates.

View full abstract

Tourist industry we say, but it is least enthusiastic about domestic tourists in the situation of Japan today. The important problem for the moment is international tourist industry, with which foreign visitors are the object. In pre-war era it occupied 14% of nation's invisible export, reaching 108,000,000 yen in 1936. In post-war times, its importance has immensely increased as the sole factor of invisible export. In 1948,6,310 foreigners entered Japan and spent 3,440,000 dollars, while in 1949, 6,070 persons spending 3,540,000 dollars have been recorded before July; and presumably, it will reach 17,000 persons and 9,980,000 dollars by the end of this year. Still this is quite small when compared with pre-war foreign money receipt of 350,000,000 dollars. Therefore, we have to foster tourist industry strongly to increase foreign money acquirement. This is still more significant as "unseen export" when our foreign trade is not quite prosperous as we desire it to be. There are three fundamental key points in development of tourist industry. They are the preservation of sources of tourist interest, propaganda to allure foreign visitors, and arrangement of receiving facilities for foreign tourists. One of the most important in arrangement of receiving facilities is lodging repletion of hotels. There are 97 hotels in Japan, and 70 of them are either occupied for army use or for exclusive use of traders, not available to the general public. Of remaining 27, no more than 10 with a total accommodation capacity of only 617 persons may be used by foreign visitors. Since entrance of traders was permitted in August 1947, restrictions in entering Japan have gradually been mitigated and, as the result, number of foreigners entering Japan is increasing as 6,310 persons for 1948 and 6,070 persons for first six months of 1949 as mentioned above. For receiving these and those who are coming increasing number in future and taking thought on poor status of existing hotels, it is quite urgent to build sufficient hotels and increase accommodation capacity. Where to build what size of hotels" are learnt when we study how foreign tourists travel around in Japan and where, how many persons, and how many days they stay, comparing these with present accommodatian capacity in places. The result is that a total of 2,172 beds are short at Nikko, Tokyo, Yokohama, Kamakura, Hakone, Nagoya, Ise-shima, Kyoto, Nara, Osaka and Hiroshima. Of these, priority must be given to Tokyo, Yokohama, Kyoto, Nagoya, Osaka, Kobe, Nara and Ise-shima. Renting of Counterpart Fund of 253,000,000 yen is anticipated for total construction expenses of 640,000,000 yen for four hotels at Nagoya, Osaka, Kobe, Nara and Ise-shima, while the other places Can not launch construction work because there is no possible way to raise the necessafy loans, although they have already concrete plans. Construction of a hotel is considerably difficult, especially under the present economic situation in Japan, for hotel business requires a great amount of fixed assets and on the other hand, it yields comparatively small profits. We have requested Hotel Construcoson Expenses several times in the Public Enterprise Budget, only to fail every time on the reason that financial condition of the government is deplorable. Now, it is the most urgent keypoint for development of tourist industry to give solution to this loan problem for hotel business by means of expanding categories of Counterpart Fund or renting Low Interest Fund of Deposit Department, Ministry of Finance or otherwise, enacting such a law as "Law of Raising Loans for Hotel Business." It is our plan to use high class Japanese style hotels for foreign visitors by means of improving them for the time-being until hotel construction is commenced with steadiness. This has been partly practised with proper success. This method will be followed for the present to get through the crisis.

View full abstract

On the measure of economical life-time of a building, we studied the functional relations by a method of cost accounting observation for maintenance and management. As the result, we obtained several formulas for the following cases: 1. The utilities of a building are constant during use 2. The utilities of a building are changed during use (1) When an enlargement of the building occurs (2) When partial improvements are made (3) When the repair expense is insufficient For case 1, a most simple formula has been derived as follows.[numerical formula]:the average rate of repair expense T: the life time of a building

View full abstract

This repont is one of the fundamental investigations for the Conventional Construction Method.

View full abstract

The theoretical formulas, described in 1st and 2nd reporte, were examined again from the results of experiment, and ultimately formula (1) was adopted in place of formula (2) which is cumbersome. It was ascertained by experiments that the possibility of succession of burning concluded by formula t→∞, v=0.14 in foumula (1) and by number of ventilation measured by using vessels of 3 diameterg larger than used in provious experiments and 4 types of ventilation and the results of burning experiment corresponded still more, it was found that the total burned weight and burning time at outbreak of fire in a room could be calculated by using formula (1) without the burning experiment.

View full abstract

A general formula which shows the grade of danger to the spread of fire in a city was found analticaly with the fire-data for Tokyo from 1935 to 1944. This formula is [numerical formula] where W is the probability that the total area, destroyed by fire once occurred, goes over S tsubo, A and B are parameters, which depend on the circumstances in that city, such as the ability to extinguish fires, building- condition and meteorological conditions. As the valuse of A and A differ for each city, they represent most suitably the grade of danger to the spread of fires in that city, because if values of these parameters are only know the probability W can be calculated for each value of S. This formula cannot be applied to small fires (S less than 50 tsubo) and conflagration (S larger than 10,000 tsubo) because their physical, quality differs much from that of the fires of medium magnitude.

View full abstract

(1) It is estimated that 79×10^5m^2 (floor area) of building will vanish every year the disasters in our country. (2) The amount of domitories and other builelings lost during the last wor is about 251×10^6m^2. The increase of demand of bwldings (inclnding domitories) by increese of populabin during the following 20 years astimated 177×10^6m^2, and 158×10^6m^2 for the supply after disasters. Total amount of supply is needed 567×10^6m^2 during the 20 year. (3) The new design of concrete building demands only 37〜40% of steel and 60% of cement in comparison with the conventinal designs. (4) The floor area 145×10^6m^2 of concrete buildings must be erected during the 20 years, and this plan only demands 2.3×10^6m^3 of lumber, (33% of its production) and 427.25×10^3 tons of steel (17% of its production) and thus plan can be realized by the industrial capability of our country. (5) This plan makes the main parts of the cities in our country safe against fires and various disasters and rescues us from the large damages which have been repeated every year.

View full abstract

This is one of the studies on the history of architects in Japan. Tradition says that Hida-no-Takumi was a skilful master of architecture in ancient times, and actually there are many old buildings which are said to have been) built by Hida-no-Takumi. According to our study, however, Hida-no-Takumi was not an individual nor an architect but it refers to a lower class of carpenters, of a period during VIII th to Xth centuries. Hida-no-Takumi was a general term used by Ritsuryo government to designate peasants of Hida province, who spent one year in the capital (Nara or Heian) to pay their taxes by working as carpenters. In this study, we have made clear who Hida-no-Takumi was and how it came to be the synonym of a skillful architect: as result we believe that it gives a perspective of the technique of architecture in Nara, and Heian period.

View full abstract