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Article type: Cover
1992Volume 442 Pages
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Article type: Cover
1992Volume 442 Pages
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Article type: Appendix
1992Volume 442 Pages
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Article type: Index
1992Volume 442 Pages
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Article type: Index
1992Volume 442 Pages
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Article type: Index
1992Volume 442 Pages
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Toshio URANO, Kiyoshi MURAKAMI, Yoshiyuki MITSUI
Article type: Article
1992Volume 442 Pages
1-11
Published: December 30, 1992
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Experimental and analytical investigations were conducted regarding the scale effect of the tensile stress-strain relationship of steel fiber reinforced concretes (SFRC). The analytical study is based on an estimation of the relationship by means of a flexural analysis considering the tensile resistance of the SFRC. The scale effect of the relationship was considered with reducing both of the stress and strain by the ratio of the flexural strength to a small beam specimen. In order to investigate the applicability of the present method, flexural tests of reinforced concrete (RC) beams with the SFRC were performed. As the results, the reasonable agreement between the measurement and calculation of a moment-curvature relationship was obtained.
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Yasuji SHINOHARA, Takeo ABE, Fukujiro FURUMURA
Article type: Article
1992Volume 442 Pages
13-22
Published: December 30, 1992
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The fracture mechanism of concrete has been investigated using the tension softening properties obtained by fitting the measured load-displacement curves in bend tests on single edge notched beams. The effects of notch depth, loading rate, maximum aggregate size, water/cement ratio, four-point bending, curing and age upon the tension softening properties are discussed. The tension softening properties can provide valuable information about the difference in the fracture mechanism between mortar and concrete, between low and high water/cement ratio, etc. Furthermore, by comparing the results of the numerical calculations using the softening model with those of the slow crack propagations observed by 50X microscopes during tests, the validity of the model and the fracture mechanism in the softening zone are investigated.
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Takayuki HIRAI, Koichi MAEDA, Shuitsu YUSA, Koichi KISHITANI, Morio HO ...
Article type: Article
1992Volume 442 Pages
23-31
Published: December 30, 1992
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Fibers which we used for asbestos substitutive materials are poly-vinyl-alcohol (Vinylon) fiber, poly-acrylo-nitorile (acrylic) fiber, and alkali-resistant glass fiber. We used mini-Hatschek machine to make test products. We used cellulose fiber to hold cement particles and mineral materials such as mica, cepiolite, wollastonite, silica fume, and bentonite, to prevent cracking and excessive length change. We have done five tests for asbestos substitutive materials, which are on bending strength, freezing and thawing resistance, impulse resistance, Incombustibility, and fiber contents. As a result, bending strength of asbestos alternative is a little low, but other properties of those are equal or better than asbestos slates. Addition of 2 % or 4 % asbestos to alternatives did not make proprieties better compared to non asbestos alternatives exept product cost.
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Hiroshi OKIMOTO, Kousuke TURUOKA
Article type: Article
1992Volume 442 Pages
33-41
Published: December 30, 1992
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This investigation, which was done by bending and subsequently straightening the bars, was carried out in order to study the bending characteristics. To avoid bending fracture in bend and return process, the bar temperature should be above 0℃ and the radius of curvature should be more than 4 × D_0 (D_0=indicated bar diameter), except for bars with c/D_0<0.031 (c=radius of ribs bottom curvature). An increase of carbon equivalent, nitrogen contents and sulfur contents are related to an increase in breaking rate of each bar. Stress concentration factor, which is a function of the bar shape properties, also affects the breaking rate.
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Yutaka YOKOYAMA, Hidenori ONO, Takamasa MIKAMI, Keisuke MURAMATSU
Article type: Article
1992Volume 442 Pages
43-52
Published: December 30, 1992
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This paper presents the relation between sinusoidal vibration or damped vibration of visual display terminal and its indistinctness as evaluation index, which is fundamental knowledges to establish the method for evaluating floor vibration. First, we made a testing device composed of a table on which CRT could vibrate and a table on which CRT could stand still. Next, using this testing device, we made a sensory scale about indistinctness of vibrating CRT by the sensory test. Finally, we picked up a physical quantity corresponded to the sensory scale, and presented the relation between them as the evaluation index.
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Hitoshi KUWAMURA, Hiroshi AKIYAMA, Yasunori KIRINO
Article type: Article
1992Volume 442 Pages
53-60
Published: December 30, 1992
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This paper attempted to prove analytically that energy input spectrum of non-linear structures excited by an earthquake motion can be predicted from smoothing the Fourier amplitude spectrum of the base acceleration. The spectral window for the smoothing process is identical to the probability density function of the time-variant vibrational frequency resulting from non-linear hysteresis. It was found that the increase in damping factor, plastic excursion, or participation of higher modes provides wider spectral windows resulting in more flattened or unaltered energy input spectra due to enhanced smoothing effects.
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Toshiro MAEDA
Article type: Article
1992Volume 442 Pages
61-70
Published: December 30, 1992
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The thin layer method allows efficient computation of the Green's functions for layered soils of finite depth, however, its application to elastic half-space requires that the infinite medium be represented by means of approximations that are analogous to transmitting boundaries. In this article, we explore the accuracy of two of these approximations in the context of the Green's functions for inplane line loads to find that the paraxial approximation of Engquist-Majda gives good results, provided that a "buffer layer" with the same material properties as the half-space separates the computational domain from the transmitting boundary.
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Saburoh MIDORIKAWA, Masashi MATSUOKA, Koichi SAKUGAWA
Article type: Article
1992Volume 442 Pages
71-78
Published: December 30, 1992
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Site effects on peak ground acceleration and velocity observed during the 1987 Chiba-ken-toho-oki earthquake (M=6.7) were evaluated. Strong-motion records at 173 sites with different site conditions were used for the analysis. The results indicate that 1) the site effects are more significant on peak ground velocity than on peak acceleration, 2) geomorphological land classification is more appropriate for evaluating the site effects than soil profile type or surface geology, and 3) the average shear-wave velocity of ground is a useful predictor of ground motion amplification at specific sites.
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Noriyuki AKINO
Article type: Article
1992Volume 442 Pages
79-89
Published: December 30, 1992
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The analytic method for pile foundations by means of elasto-plastic finite element method based on vertical loading test was proposed. The ground element including around pile top is taken as an elasto-plastic material which rigidity is changed with the increment of strain, and the pile skin friction model is supposed as elasto-plastic model. In the pile vertical loading tests this method is effective on the pile quantitative and qualitative analysis that are about characteristics both settlement and transmission of the axial force. That is possible to precisely recreate actual settlement characteristics by this method.
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Kuniyoshi INA, Hideaki KISHIDA
Article type: Article
1992Volume 442 Pages
91-100
Published: December 30, 1992
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A stability diagram is proposed for the design of piles in clay under cyclic axial loading. The diagram represents the allowable combination of average load (Q_<ave>) and cyclic load amplitude (Q_<amp>). The boundary lines between stable and unstable zones are defined by the following relations : (1) Q_<max>≦Q_y ; (2) 2 Q_<amp>≦Q_y ; where Q_<max> is the maximum value of cyclic load (=Q_<ave> + Q_<amp>) and Q_y is yield load obtained by pile load tests. The diagram is compared with the results of field and laboratory tests reported in the literature.
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Shiro KATO, Yoichi MUKAIYAMA, Takashi UEKI
Article type: Article
1992Volume 442 Pages
101-109
Published: December 30, 1992
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The present study investigates the dynamic response of single layer latticed domes subjected to self-weight and horizontal seismic forces. A model for analysis is a hemispherical latticed dome of 60 m-span. Firstly, linear dynamic response analysis was performed to calculate the story shear coefficient C_i of the dome. And, we showed C_i distribution could be estimated from normalized response spectra. Secondly, static buckling analysis was applied to investigate buckling property of a unit truss which would represent the foundamental behaviour of the dome subjected to horizontally repeated forces. Thirdly, the elasto-plastic buckling load of the dome under self-weight and static horizontal seismic force was examined by elasto-plastic buckling analysis. In this analysis, C_i value was utilized for the equivalent static horizontal force. These results revealed that the static buckling load might be approximated in a reasonable preciseness by combined use of generalized slenderness ratio and a linear buckling analysis. Lastly, the static buckling load was compared with its dynamic buckling load, considering both geometry and material nonlinearities.
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Morihisa FUJIMOTO, Shigekatsu ICHIHASHI, Akira WADA, Kazushi SHIMAZAKI ...
Article type: Article
1992Volume 442 Pages
111-121
Published: December 30, 1992
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Reinforced concrete structures had been struck by big disasters at every times when the large earthquakes occurred in last 50 years. The structures were destroyed for quite short period about one minute or more due to earthquake ground motion. However, there were only several studies of the real time testing for reinforced concrete columns. About 1/2 scale reinforced concrete column models (shear span ratio = 1.5) of the real structures were prepared. The one way and cyclic lateral forces, which have same velocities as responses under earthquakes, were performed to these columns on that vertical loads were working. This paper describes these experiments and results.
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Katsuki TAKIGUCHI, Hisato HOTTA, Tomoki MIZOBUCHI, Shuhei MORITA
Article type: Article
1992Volume 442 Pages
123-131
Published: December 30, 1992
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Frexural strength of R/C member is generally calculated, based on the Bernoulli's assumption, and using the concrete strength obtained from the cylinder test. As for a short column subjected to compression and shear-bending, the calculated strength often becomes lower than the experimental strength. The present authors consider that the disagreement between the calculated strength and the experimental strength is caused by using the cylinder test result, but this has not been investigated in detail. This paper aims to make clear the compressive properties of concrete in R/C member. The behavior of concrete around the critical section of R/C column were examined through a shear-bending test under compression. An equivalent rectangular stress distribution is assumed to calculate the concrete strength. As a result, the concrete strength at the critical section is 1.5 to 2.0 times higher than the strength obtained from the cylinder test.
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Masayuki HAMAHARA, Yasashi NAKAYAMA, Junjiroh MOTOOKA
Article type: Article
1992Volume 442 Pages
133-139
Published: December 30, 1992
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In this paper, we present analytical approach based on a lower boundary theorem using a truss and arch model, for predicting the ultimate behavior of prestressed concrete beams with web openings. Comparison of systematic test results was made in terms of the ultimate strength and modes of failure. Based on the comparison, we present a rational design method to prevent the premature failure at the openings
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Shin KOYAMA, Kazuoh SEO, Takanori SAMANO
Article type: Article
1992Volume 442 Pages
141-146
Published: December 30, 1992
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During the 1984 Nagano-ken-seibu earthquake, a rather-long period significant later phase due to Love-waves appeared after one minute from the principal groumd motion at the Kumagaya JMA station. In order to estimate the paths of these Love-waves, the ray tracing method is applied and two paths from the western part of Nagano prefecture to Kumagaya were estimated. One reaches Kumagaya directly and the other from NW direction through a narrow sedimentary valley. It's also attempted to predict the earthquakes which will make Love-waves propagate to Kumagaya. There are two paths oriented by the sedimentary valley, and they reach the western part of Nagano prefecture and the south off Kanto district.
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Yoshifumi SAKUMOTO, Tanemi YAMAGUCHI, Tadayoshi OKADA, Youhzoh SAITO, ...
Article type: Article
1992Volume 442 Pages
147-156
Published: December 30, 1992
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This paper presents experimental results of a full-scale fire test with loading by Fire Resistant steel (FR steel) beams and their numerical analysis. Sprayed rockwool and an intumescent coating are used in providing FR steel's fire protection. Experimental results show that FR steel beams can bear a load corresponding to two-thirds of their room temperature yield point at 600℃, reduce the thickness of rockwool compared to conventional steel beams, and provide one hour of fire resistance with an intumescent coating. Also, a numerical analysis shows that it is possible to simulate fire resistance time and deformation behavior by the numerical properties of FR steel and an elasto-plastic creep thermal deformation analysis.
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Takuji HAMAMOTO, Yasuo TANAKA
Article type: Article
1992Volume 442 Pages
157-167
Published: December 30, 1992
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An analytical approach which predicts the dynamic behavior of a circular flexible floating island subjected to wind-induced waves is presented, taking into account the dynamic interaction among the island, sea water and anchor system. The floating island is modeled as an elastic circular plate with tension-legs. Based on a linear potential flow theory, the hydrodynamic pressure generated on the wetted surface of the island is obtained in closed form. The modal equations of motion of the island with or without anchor system are derived by energy method. The response quantities are evaluated as root-mean-squared values using a stationary random vibration theory. Numerical examples are presented to discuss the effects of anchor arrangement and wave characteristics on the island response.
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Article type: Appendix
1992Volume 442 Pages
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Article type: Cover
1992Volume 442 Pages
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