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Article type: Cover
1991 Volume 419 Pages
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Published: January 30, 1991
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Article type: Cover
1991 Volume 419 Pages
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Article type: Index
1991 Volume 419 Pages
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Article type: Index
1991 Volume 419 Pages
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Article type: Index
1991 Volume 419 Pages
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Tatsuo OKAJIMA, Jian-dan WU, Tetsumi HORIKOSHI, Shinji KAWABE, Yuji TA ...
Article type: Article
1991 Volume 419 Pages
1-10
Published: January 30, 1991
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The object of this paper is to clarify the effect of temperature on the tactile response of building materials. The tactile (warmth, hardness, roughness, dryness, comfort) values of sixty materials were experimentally determined at the temperature of 10, 20 and 30℃. Within the room temperature of 10℃ to 30℃, psychological values of hardness, roughness and dryness are constant. Warmth values can be obtamned by the following equation. W_T=W_<20>+0.030(T-20) Where WT is tactile warmth value at T℃, W_<20> is tactile warmth value at 20℃, and T is the room temperature ℃. The tactile comfort values can be expressed by the following equation. Ar=(-0.10T+2.0)W_r+ (0.063 T-0.63)H_r+(-0.096T+0.96)R_T Where A_r is tactile comfort value at T℃, H_r is tactile warmth value at T℃, R_r is tactile hardness value at T℃, T is tactile roughness value at T℃ and T is the room temperature ℃. The tactile dryness values can be expressed by the following equation D_r=0.40R_<20>+0.60W_<20> Where D_r is tactile dryness value at T℃, R_<20> is tactile roughness value at 20℃, and W_<20> is tactile warmth value at 20℃.
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Hidenori ONO, Takamasa MIKAMI, Takao KASHIBUCHI, Yutaka YOKOYAMA
Article type: Article
1991 Volume 419 Pages
11-19
Published: January 30, 1991
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The purpose of this study is to present an evaluating method of scratch resistance of finishing materials from a viewpoint of visual perception. The results of this study is as follows. 1) A scratching apparatus was newly designed and produced which can give scratching effect to the surfaces of finishing materials under conditions similar to actual circumstances. 2) Two sensory scales which indicate the degree of scratch were composed on two sets of scratched samples by means of sensory test. One set of samples were made by actual human scratching, and other set of samples were made by the scratching apparatus. The validity of the apparatus was verified from the high correlation between two scales. 3) Physical quantity properly corresponding to the sensory scales was extracted from the analysis of color difference and gloss data of the samples. 4) An evaluating method of scratch resistance of finishing materials was presented, with an evaluating index based on the relation between an evaluating scale of scratch and the physical quantity, and with a scratching method of object materials.
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Hiroshi HASHIDA, Kyoji TANAKA, Michio KOIKE
Article type: Article
1991 Volume 419 Pages
21-29
Published: January 30, 1991
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Remaining moisture in concrete with some drying time begins to change its distribution after the drying surface is sealed up. This paper describes an investigation into such a moisture redistribution in order to discuss the effect of moisture in concrete on the failures of the finishing layers applied directly on concrete substrate. In the experiment both pore humidity and moisture content in concrete standing for a slab on deck plate were measured before and after the drying surface was sealed with a vapor-tight surface layer. After being sealed the pore humidity in concrete began to change its distribution, and finally the portion under the surface layer became highly humid in spite of a long period of drying. This moisture redistribution may cause the failures of the finishing layers. From the measurement of the moisture content, however, such a moisture redistribution could hardly be recognized. The difference between the redistributions of pore humidity and moisture content is due to the hysteresis of the sorption isotherm of concrete. A numerical estimation of the moisture behavior in concrete with consideration of the hysteresis was also presented. The estimation presented was proved to be very useful for the discussion of the moisture load against the finishing layers.
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Rinji KANEKO, Sakichi OHGISHI
Article type: Article
1991 Volume 419 Pages
31-38
Published: January 30, 1991
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Direct-tension and splitting tensile fatigue tests were performed on air-dried and wet concrete. The conditions in the fatigue test are following ; 10×10×40 cm and 10φ×17 cm specimens, loading at 1H_z and S_<max>=(0.9〜0.7)S, S_<min>=(0.1〜0.4)S. The following conclusions were obtained from the tensile fatigue test results on plain concrete. (1) The relation between the loading stress ratio and the number of cycles to failure in the tension fatigue is different for air-dried and wet concrete; and the fatigue life in wet concrete is shorter than the dryed one under the same test conditions. (2) When direct-tension and splitting tensile fatigue are compared each other, the fatigue life in splitting tensile test is smaller than the former test under the same minimum stress ratio. (3) The fatigue strength of concrete in the splitting tensile test is lower about 20 % than that in the direct-tension test. (4) The following expressions were derived for air-dried concrete. S_<max>=1-0.0285(1-log (S_<min>)) logN_f where, S_<max> is the maximum stress ratio for the ultimate strength, S; Smin is the minimum stress ratio for the ultimate strength; N_f, is the number of loading cycles at fatigue failure.
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Kuniyuki TOMATSURI, Kenji KUROHA
Article type: Article
1991 Volume 419 Pages
39-46
Published: January 30, 1991
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Is compensating strength in winter to high strength concerte needed? Investigation on strength gain after 28 days and relation between strength and maturity was made carefully to 3 projects 13 different mix design concrete The result is that design strength is obtained after 28 days without any additional strength in winter on the condition that bads ratio is below 2. 3 %
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Tadatsugu KAGE, Yoshiyuki MITSUI, Kiyoshi MURAKAMI, Hiromichi SAKAI
Article type: Article
1991 Volume 419 Pages
47-56
Published: January 30, 1991
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Experimental investigations were conducted to clarify the effect of CFRC-clad reinforcements on flexural characteristics of reinforced concrete (RC) beams. Pitch-based high-performance carbon fibers were used for making the CFRC. The CFRC-cladding was performed on the tension side of the beam. The concrete and reinforced concrete beams with CFRC-clad were tested under pure bending loads. The RC beams with CFRC-clad including reinforcing steel bars were also tested. Main conclusions obtained were as follows; 1) The CFRC-cladding had remarkable effects on increasing of the cracking load. And the most effective thickness of the CFRC-clad was found out. 2) The yield strength and absorbed energy of the beams were increased by the CFRC-clad in cooperation with the reinforcing steel bars.
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Yasuhiro HAYASHI, Hiroshi KATUKURA, Takahide WATANABE, Shunichi KATAOK ...
Article type: Article
1991 Volume 419 Pages
57-66
Published: January 30, 1991
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This paper presents the reconstruction method of a displacement wave form from the accelerogram. The method is based on a relation between the real part of Fourier transform, of a causal time series and the original time series, and is based on the following fact. When a high-pass filter is applied to a reasonable function with a zerofrequency singularity, the spectral energy removed from the real part of Fourier transform is relatively insignificant compared to that removed from the complex part. Therefore, the presented analysis results in a less distorted, displacement waveform. In order to demonstrate the validity of the integration method, vibration test of digital strong-motion accelerographs (SSA-1 and SAMTAC-17) are carried out by three dimensional shaking table, and integrated displacements is compared with the corresponding shaking table displacements.
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Hidemori NARAHASHI, Minoru MAKINO, Syuichiro OMOTE
Article type: Article
1991 Volume 419 Pages
67-76
Published: January 30, 1991
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It is important to give physical evaluation to the intensity of the ground motion which have been indicated by the seismic damage of wooden houses, especially for the earthquakes before 1960's in Japan. In this paper, assuming that the seismic damage of Japanese wooden houses built in the traditional manner have been caused by the relative displacement of response during earth-quake, the statistical distribution of yielding strength and other characteristics of wooden houses were surveyed. After the response analyses, it is concluded that the maximum displacement of a wooden house can be estimated by the Fourier spectrum of the ground acceleration |Ga|. The values of |Ga| correspond to 16, 50 and 84 % in the rate of collapsed house were estimated and compared with the values of B/H which is the seismic intensity defined by overturned tomb-stones.
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Tsuneo YAMAGUCHI, Kazuhiro NAGANUMA
Article type: Article
1991 Volume 419 Pages
77-86
Published: January 30, 1991
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The present study focuses' on mechanical characteristics of reinforced concrete (RC) panels under in-plane shear stress with ultimate strength determined especially by concrete failure. Monotonic loading tests were conducted using 32 RC panels with concrete cylinder strength, reinforcement ratios and load combinations with axial compression as parameters. The principal factors governing constitutive law of concrete were studied from the above test results. As the result, it is concluded that the reduction of concrete compressive strength under in-plane shear stress depends on not only the principal tensile strain, but the cylinder strength and axial compressive forces as well.
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Junji OGAWA, Yoshihiro ABE, Michio HOSHI, Masahiro IKUTA
Article type: Article
1991 Volume 419 Pages
87-98
Published: January 30, 1991
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Cantilever-type reinforced concrete column specimens are used for uniaxial and biaxial static lateral loading tests. Specimens are approximately full scale models considered to be representative of the first story interior columns in typical three to five storied buildings in Japan. The behavior of cracking and spalling of the reinforced concrete columns specimens under, the action of biaxial loading could simulate somewhat the earthquake damage features of frame-type RC buildings observed in the past strong earthquakes. The biaxial loading gives more serious damage to the concrete columns than the uniaxial one. According to the crack-spall off damage index, discussed in this study, (1) If the crack length ratio is around 10 and the spall off area ratio is from 10 to 30 %, the maximum ductility should be around 3. (2) If the spall ratio is more than 50 % and transverse bars become loose and longitudinal bars buckle, the maximum ductility should be more than 5.
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Yoshinobu FUJITANI, Daiji FUJII
Article type: Article
1991 Volume 419 Pages
99-106
Published: January 30, 1991
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This paper presents a procedure for the finite element analysis of high-order elastic fundamental solutions in two-and three-dimensional bodies. Three-dimensional fundamental solutions can be expressed by the Fourier's Series expansion with respect to the Coordinate ψ. Its Second-order solution correspond to the plane symmetric fundamental solution (Cerruti's solution) and is formulated in this paper by finite element method. Two-dimensional higher-order fundamental solutions under following load conditions are analysed by finite element method: (1) a couple, (2) equal and opposite moment of couples, acting on the straight boundary of an infinite plane. It is clarified that the usual two-dimensional fundamental solution can be solved by a simultaneous equation, however, the above higher-order two-dimensional fundamental solutions are analysed as eigen-value problem. By the present finite element method, the numerical fundamental solutions were obtained with good convergence.
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Tsuyoshi TAKADA
Article type: Article
1991 Volume 419 Pages
107-119
Published: January 30, 1991
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A new stochastic analysis method based on the Bubnov-Galerkin method is proposed herein for estimating the response variability of systems with spatially varying flexural rigidity. Such a flexural rigidity is idealized as a multi-dimensional, statistically homogeneous, continuous Gau's-sian stochastic field. In the formulation of this method, a set of deterministic trial functions are introduced, and hence the resulting response can be expressed in terms of the trial functions with non-Gaussian random coefficients. Two kinds of techniques for approximating the response statistics are utilized: a first-order perturbation technique and the Monte Carlo simulation technique. Bending problems in which the flexural rigidity either of elastic beams or rectangular plates has spatial variability are treated. Two numerical examples, a both end-fixed beam and a four-edge clamped square plate, are presented along with the conventional stochastic finite element method. The result from the proposed method shows reasonably good agreement with those from the conventional method. Finally, the proposed method is expected to make it possible not only to develop a new stochastic finite element method, but also to treat dynamic and/or nonlinear stochastic problems by virtue of the Galerkin approximation.
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Mitsuo NAKAHARA
Article type: Article
1991 Volume 419 Pages
121-134
Published: January 30, 1991
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Wind damage of roofing elements occure very often in the event of strong wind. The problem of the structural safety of the elements comes to the problem of wind loads on the elements. The wind loads on the" elements should be estimated by the difference of external wind pressure on the elements and internal wind pressure under the elements. But, the properties of the internal wind pressure have not be clarified, enough. In order to investigate the properties of the internal wind pressure, wirid tunnel tests on the roofing element models are caried out. In this paper, the methods of the modeling of the roofing and wind tunnel testing are discribed, and the records of fluctuations of the external and internal wind pressure on the roofing element models are showen. The Wind pressure coefficient distributions of average and fluctuating pressure are shown. And it is confirmed that if the external wind pressure distribution, Q-ΔP relation (equation 2.1) and equivalent flow coefficient are given, the internal wind pressures can be estimated.
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Yoshiaki HISADA, Shunroku YAMAMOTO, Sukenobu TANI
Article type: Article
1991 Volume 419 Pages
135-143
Published: January 30, 1991
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An analytic method is proposed for Love wave field generated at a vertical interface between two 2-D elastic quater-spaces; one homogeneous and the other multi-layered (see Fig. 1). The incident field is a plane SH-wave whose amplitude varies with depth, propagating horizontally in the first quarter. The Love wave transmitted into the second quarter is expressed using the Representation Theorem and the normal mode solution of the Love wave. When imposing continuity condition for displacement and traction at the vertical interface, the diffracted waves in the first quarter and the body waves in the second quarter are neglected. The integration along the vertical interface is analytically performed, assuming constant amplitude of the incident wave within each layer at the interface, and using the fact that the amplitude of the normal mode solution decreases exponentially, which guarantees rapid, convergence of the intergral. To check the accuracy of our solution, we have computed theoretical seismograms at stations along the free surface of two sedimentary basins embedded in a homogeneous half-space for the case of incident SH-waves from a shallow dislocation source (see Fig. 2). Results are in excellent agreement with the corresponding results by the boundary element method, with the advantage that the proposed method requires much less computational time (see Figs. 4 and 6).
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Toshiyuki NOJI, Hidetoshi YOSHIDA, Eiji TATSUMI, Hideyuki KOSAKA, Hiro ...
Article type: Article
1991 Volume 419 Pages
145-152
Published: January 30, 1991
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The vibration control effect in an actual structure of a vibration control damper using the fluid force of water is discussed in this study. The building where the damper was applied is a tall panoramic tower 158 m in height. The damper was installed to reduce vibration of the building in the transverse direction due to wind. Forced vibration experiments, free vibration tests, microtremor measurements, and wind vibration observations were carried out for cases with and without the damper in order to verify the vibration damping effect of the damper. The following conclusions were drawn as a result of these tests and observations: (i) It was ascertained that this vibration control damper was effective against steady-state and random forces. (ii) The calculated value according to the analysis technique proposed corresponded well with experimental values.
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Katsuki TAKIGUCHI, Hisato HOTTA
Article type: Article
1991 Volume 419 Pages
153-162
Published: January 30, 1991
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This paper discusses thermal and shrinkage stresses occured in concrete at early age. It is considered that they are very important factors to clarify a fractural mechanism of concrete, because the stresses often cause the cracks in concrete. But there are no researches which deal with thermal stresses and shrinkage stresses together. When they are analyzed, it is necessary to define a degree of hydration reaction under any conditions of temperature and humidity. The degree of hydration reaction was examined experimentally, and is formulated as the function of temperature and water content of concrete in this paper. A numerical stress analysis method is proposed based on Fourier heat equation and water diffusion equation, and the stresses occured in a concrete column of 60cm×100cm section are analyzed using the analytical method above mentioned.
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Ching-yuan LIN, Shinichi SUGAHARA, Tomohiro NARUSE
Article type: Article
1991 Volume 419 Pages
163-168
Published: January 30, 1991
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A model is proposed, aimed at predicting the critical heat-release of flame emergence through a compartment opening. With the growth of fire, airflow into flame through opening comes to influence flame behaviour. The characteristic velocity of Froude number as a function of flame length is considered to be that of inflow air. The results of fire experiments performed by a 1/5-scale model with one opening show that there exists a relation between the ratio of the height of opening to the characteristic length of compartment and the ratio of the ventilation parameter to the critical heat-release.
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Article type: Appendix
1991 Volume 419 Pages
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Article type: Cover
1991 Volume 419 Pages
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