The radiation dose to the biological shield concrete of the JPDR(Japan Power Demonstration Reactor; where electric power had actually been generated for some years, was evaluated and the radiation effect on the compressive strength of the concrete was investigated. The data obtained can be used a fundamental information for predicting the life time of a large commercial nuclear power plant. The major results of this study are summarized below. a) The maximum dose of the fast neutron and -f-ray at the inner surface of the biological shield concrete are 1.11×10^<18>n/cm^2 and 4.77×10^<18> Gy, respectively, at the level of the reactor core, The generation of heat within the shiled concrete is similar to that of the distribution of the γ-ray flux. b) The maximum fast neutron dose irradiated to the concrete samples used for the measurements was 1.11×10^<18>n/cm^2, which is almost the same level as that at commercial nuclear power plants. The compressive strength of the concrete samples increased with the fast neutron fluence, which depended on the distance from reactor core level.

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The object of this paper is to clarify the effect of the surface temperature on the tactile response of building materials. The tactile (warmth, hardness, roughness, dryness, comfort) values of nine kinds of building materials were experimentally determined with varied surface temperature at constant room termperature. It was found that the values of warmth, hardness and roughness can be predicted by the compact tactile sensor.

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The purpose of this study is to establish a relative evaluation method of floors and pavements from a viewpoint of slipperiness on braking a bicycle. In this paper, part 2, first, the indefinite factors were eliminated from the physical properties presented in previous study, part 1. Second, the slip meter for evaluating the slipperiness of floors and pavements more efficiency was newly designed and manufactured. And we proved the slip meter was adequate. As a result, the more efficient evaluation method was presented through the experiment using newly developed slip meter for evaluating the slipperiness.

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On the basis of observation on blisters of epoxy resin floor coatings in actual buildings and some experiments in a laboratory, we proposed the accelerated method to reproduce blisters on concrete substrate. Then, we made clear the level of pressure in blisters artificially produced. To determine the existence of driving force of pushing coatings up, the semi-permeable property of concrete was furthermore studied by the two measurements such as water flux and osmosis pressure between ethyl cellosolve solution which is one of the constituents in liquid in a blister and distilled water. Finally, the mechanism of blistering of floor coatings applied on concrete substrate was described.

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This paper deals with conical vortices on a flat roof of a low-rise building when the incident flow is for oblique angle. A flow visualization technique is devised and presented that uses the inside space of the model as a mist reservoir. Flow patterns on a flat roof are investigated by means of flow visualizations with laser sheets and a strobe light. It is clarified that the sway of conical vortices is induced by the switching of vortices formed by separating flow. Also the exist of two pairs of vortices extended from the vertexes of the roof is pointed out.

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To estimate the amplification characteristics of the ground motions in the heavily damaged belt zone in Kobe City during the 1995 Hyogo-ken Nanbu earthquake, 3-D wave propagation analyses of a 2-D deep irregular underground structure model with vertical discontinuity were performed using the hyperelement method for incident plane waves expected from the wavefields due to the source mechanism. The incident waveform at bedrock is evaluated by deconvolution analysis using the observation record at Kobe University. The ground motion at the surface of the Osaka group layers and at ground surface are calculated. The effects of the deep irregular underground structure and shallow surface layers on the ground motion amplification are discussed. The analytical results show that the ground motions in the heavily damaged belt zone were amplified due to the focusing effect in the deep irregular underground structure as well as the shallow surface layers, and that the calculated maximum acceleration distributions coincide closely with the distribution of structural damage.

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Hitherto, the overturning of rigid bodies under earthquakes have been dealt with in terms of the maximum ground accelaration and the maximum ground velocity. However, the adequate estimate for all shapes and sizes of rigid bodies has not been established yet. In this paper, the energy approach is applied to the overturning problem. By introducing the equivalent period of vibration, the energy inputs to rigid bodies are estimated based on the energy spectrum. The possibility of overturning is judged by equating the energy input to the potential energy of rigid bodies on the brim of overturning.

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Unified and effective hybrid stress finite element method for shear-deformable plane beam-column is developed. In order to evaluate the influence of warping and shear deformations right and precisely, shear deformation beam-column theory based on the assumption of no in-plane strains of the section, higher order than the well-known Timoshenko's theory, is adopted. According to Refs.1)-3), hybrid stress method is unifiedly formulated for the present theory, and a new series of higher order shear-deformable plane beam-column elements is derived. Several numerical tests for simply supported beams are performed, and show that the present approach have excellent capacity to simulate accurately the more complicate behavior accompanied with the warping deformation for both slender and thickset beam-column.

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Lateral resistance of pile near a cliff is lower than that of pile installed in a flat land. The authors carried out a series of simulation analyses by FEM and model lateral load tests of piles, and proposed the method for estimating lateral subgrade reactions which have non-linear characteristics of soil under those conditions. And that, we confirmed that non-linear behaviour laterally loaded pile near a cliff can be analyzed as a beam on the multi elastic layer by applying the proposed method.

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The purpose of this study is to reveal the dynamic mechanism, which governs the complicated vibration phenomena of an elasto-plastic system with geometrical nonlinearity, from the viewpoint of the theory of nonlinear vibration. The periodic solution and its stability are discussed for an Blast o-plastic single-degree-of-freedom system. The influence of the geometrical nonlinearity on the elasto-plastic vibration and the instability caused by the plasticity are explained with these periodic solutions. The comparison between the periodic solutions and the time-domain responses on the phase plane shows several interesting characteristics suggesting the mutual relation.

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The present paper studies the dynamic collapse characteristics of relatively low-rise latticed spherical domes subjected to horizontal earthquake motions. First, the equivalent and static seismic forces for static analysis are calculated by elastic linear time-domain analysis adopting two acceleration records of ELCENTRO-NS and TAFT-EW. Secondly, the elasto-plastic buckling loads of the domes under both the self-weight and the static seismic force are examined by elasto-plastic buckling analysis. These results reveal that the static buckling loads may be estimated with reasonable preciseness by combined use of generalized slenderness ratio and a linear buckling analysis. Lastly, the static buckling loads, statically estimated, are compared with the corresponding dynamic buckling loads, considering both geometrical and material nonlinearities.

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In order to grasp the structural behaviors of a new type of single-layer lattice shell consisted of aluminum members and joints, the following researches had been planed and performed : (1) Experiment of structural elements such as member and joint, (2) Experiment of small-scale models. These results were presented in the reference [1]. In this paper, analytical researches on the structural behaviors of the single-layer lattice shell consist of aluminum members and joints are performed. This single-layer lattice shell has the insertion joint system which has a varied type of an edge shape of tubes and an uneven shape of insertion joint with a hab and fillers. In the first part, analytical studies, using the finite elememt method, on the structural behaviors of the edge shapes of tubes and the uneven shapes of the insertion joint in the hab are shown. In the second part, using this analytical results, the analytical model of the tube with the insertion joint are presented. In the last part, non-linear analyses of the three kinds of small-scale models with a diameter of 4.2 meters which were examined in the reference [1] are performed.

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A new method is presented for shape design of membrane structures. The structure is modeled by the finite element method, and explicit conditions are derived for the curved surface to be reduced to a set of plane cutting patterns after removing the pretensioning force. By using the derived conditions, an inverse problem is formulated to directly find prestresses as. well as the shapes of the cutting patterns for specified nodal coordinates. Then a trade-off design problem is defined for minimizing the weighted sum of the variances of the initial stress and the shape from. the desired values. In the examples, trade-off designs are found for a HP-type membrane structures, and the validity of the assumptions used in the formulation is verified by carrying out nonlinear shape-finding analysis.

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In general, as the horizontal rigidity of an architectural structure was extremely high, structural analysis and structural calculations were carried out under the rigid floor assumption. However, because it is not appropriate to assume the horizontal rigidity of floor to be completely rigid in the timber structure, the deformation of the floor can not be disregarded. This paper is an experimental and analytical study of the influence of the horizontal rigidity of the floor on the vibration characteristic in the timber structure. As the first step, the vibration characteristic was investigated by the vibration test using the 1/3 scale model of the timber structure (1 Story, Span direction :1 bay, Longitudinal direction :1-3 bays) with various floor rigidities. After confirming adaptability as an analytical model of the three dimensional shearing vibration model (mass is concentrated on the top of pillar) used for the analysis, we examined the influence of floor rigidity upon the vibration characteristic of structure using ten-supan analitical models.

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A model based on upper bound theorem was proposed to give shear failure surface of R/C columns subjected to vertical and biaxial horizontal loads. The failure mechanism assumed in the model was defined by four parameters, and the solution was obtained theoretically. The effect of axial load, direction of horizontal load, and amount of lateral and vertical reinforcement on shear strength was studied by using the proposed model. The study has revealed that: (1) there is interaction between vertical load and shear strength, (2) the shape of shear failure surface under constant vertical load is an ellipse and the direction of displacement coincides with the one normal to the surface, and (3) vertical as well as lateral reinforcement influences shear strength.

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The objective of this study is to propose a equation for estimating design natural periods of prestressed concrete structures in ultimate strength design method. General lumped mass systems (2 thru. 12-story trial frame) were examined by eigen value analyses with parameters, i.e., dimensions of columns and girders, numbers of frame span, and span lengths. Through the analytical results, a primary equation based on relations between structure heights and natural periods was derived. A proposed equation for the ultimate design was introduced on the basis of the primary equation and evaluation of availability for design shear forces checked by dynamic analysis.

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The thickness and residual stress effect of fatigue performance was inverstigated on non-load-carrying fillet welded joints with thickness ranging from 12 to 38mm. As-welded and stress relieved joints were tested under both alternating and pulsating bending. Material fatigue tests on hour-glass type specimens and fatigue crack grouth tests on edge-notched specimens were also performed under fully reversed axial load and alternating and pulsating bending, respectively. In this paper, results of the tests are presented and discussed. Some aspects of fatigue performance are shown in relation to the thicknass and residual stress effect.

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The laws of scaling for unsteady-state smoke movement were derived by dimensional analysis of the governing equations (continuity, conservation of momentum and conservation of energy) and the boundary condition at the flames and the wall. Experiments were conducted in two stages, two different sizes (1:2.5)and real fire test and its reduced model (1/40). And the similarity in each stage was almost confirmed.

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This would be a well-written paper enlarging the availability of questionnaire survey of seismic intensity originated by Y.Ohta. The proposed method that mail shot targets are convenience store's owners needs less work amount to distribute and retrieve a lot of questionnaire sheets; however, the obtained seismic intensity might be impossible to keep accurate enough for microzonation. The accuracy of seismic intensity in the above paper should be discussed.

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Answers against comments from Prof. Okada are summarized as below. His critical reading of the paper, appropriate and constructive comments and strong encouragement to us are deeply appreciated. (1) As the accuracy of estimated seismic intensities are not still clear in our approach, our results should be expressed in a figure of significant number, such as JMA seismic intensity scale. (2) Also, careful treatments should be given in the use of our results for seismic microzoning. (3) Estimated seismic intensities from our method showed a large scatter comared with those from conventional method.

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