It is clarified based on the analysis of foot movement in walking that there is very little danger of stumbling if the height of difference in level is within 5 mm. Sensory and perceptual evaluations concerning the pain at stumbling and the danger of tumbling were quantified as evaluation scales by means of a sensory test. Then proper physical quantities corresponding to the scales were established using a newly-depeloped measuring apparatus. Finally the relationship between the scales and the quantities were presented as evaluation indexes of the safety of difference in level.

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An analytical verification was conducted concerning the propriety of the method which is called J-integral equivalent Dugdale model here. The present model can be analyzed based on linear elasticity by means of substituting Dugdale model with the same J-integral value for any relation between cohesive force and crack opening displacement in the cohesive force model. Since the cohesive force model is a non-linear elastic one, a load-displacement curve after cracking must agree with a curve which links cracking points for different pre-crack lengths. As the result of the analytical verification, a good agreement between them was obtained considering the errors of Dugdale model analyses.

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The results of experimental tests conducted on the shear walls reinforced by the new method are presented in order to develop the reinforcing method to increase ductility of framed shear walls for which the predominant action is shear. This new method is to confine the potential shear failure regions of edge columns in steel tubes. The experiments conclude that the ductility of the shear walls reinforced by the proposed method is increased remarkably by preventing the shear failure of edge columns completely. This is hard to prevent by conventional methods such as hoops. It is also clarified that the shear strength, deformation and ductility factor of these shear walls are estimated quantitatively by the analysis based on the arch mechanism.

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A hinged type macro-model developed by the authers is used to formulate a mathematical and explicit approach to clarify the failure modes of R/C and SRC columns subjected to combined bending and shear under constant compressive axial force. At first, with the assumption of the stress-strain relation of materials to be bi-linear, 18 types of stress states of hinge are considered. Then, by defining the failure modes of column, these 18 types of stress states are grouped into 6 failure modes. Conditions for these failure modes to occur are given in an explicit format. As an extention example, conditions for the edge columns of shear wall not failing in shear are developed.

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Application of high-strength fibre rods as reinforcement for concrete structures in order to improve durability, strength, and electromagnetic characteristic is actively studied. In this paper, the authors examine the flexural crack behaviour of concrete specimens reinforced with braided carbon fibre rods or braided aramid fibre rods subjected to uniaxial tension and flexure. The test results demonstrated that the method to estimate the maximum crack width as proposed for steel reinforcement could be applied to the fibre rods, if the average strain of fibre rods considering tension stiffening effect and the average crack-spacing as a function of the average strain of fibre rods were obtained.

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The strong ground motion during the future large earthquakes have been evaluated at Yokohama, the coastal alluvial deposit site, for aseismatic design of a high-rise building synthesizing the moderate seize earthquake records observed at the site. From the engineering point of view, selected the future earthquakes to be the recurrence of 1923 Kanto earthquake and hypothetical Tokai earthquake which was reported by Land Agency. Since the site is very close to the 1923 Kanto erthquake fault plane, we utilized three element earthquakes to get rid of the effects of propagation paths. While, in the case of Tokai eathquake, only one element earthquake was used because the epicentral distance is more than 100 km and in such a situation, it was thought that the effect of source mechanism may be neglected. If we assign the Neogene rock to be the free surface at the site, the maximum ground acceleration and velocity for kanto and Tokai eathquakes were found to be 330 Gal, 40 cm/s and 115 Gal, 20 cm/s respectively. The derivings agree well with maximum acceleration of 1923 Kanto earthquake deduced from the damage rate of wooden houses. Numerous observed data obtained near the focal regions are also in favor our results. Through the study, we came to the conclusion that the reexamination of the present status of earthquake loading system for the aseismatic design of structures is necessary. Thus, we propose the methodology of estimating the eathquake load and level of the ground motion. Since our methodology may not be complete, because there remains a lot of problems to be solved, we will try to improve our methodology by introducing the new findings in the future.

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This study aims to evaluate damage of single story structural models with one-axis eccentricity subjected to strong earthquake ground motions in the x-and y-directions, simultaneously. The strength capacity and design shear forces of single story structures with eccentricity are examined by considering the corresponding strength capacity ratio, '^eR-value'. Various types of single story models with one axis eccentricity are computed by a linear and nonlinear dynamic response analysis. In addition, nonlinear response of the damage side edge perimeter is also predicted by the linear response of single story models with one axis eccentricity using '^eR-value'.

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Scattering of harmonic waves by subsurface irregularities is studied experimentally with the detailed measurements of a surface ground motion generated by forced vibration of a reinforced concrete model footing placed on a subsurface irregular ground. Each of three different footings was excited in three kinds of directions to generate different patterns of wave propagation. Observations indicate that the variations of measured velocity amplitude are most influenced by SH wave motion among various types of propagating waves and that they are highly frequency dependent. They also indicate that the measured velocity amplitudes do not always decay monotonously with increasing the source-receiver distance and that it is the measurement points of the filling ground in the vicinity of interface between the cutting ground and filling ground that surface ground motions are significantly amplified.

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A nonlinear Tuned Liquid Damper (TLD)-structure interaction model has been developed to investigate the effect of nonlinearity in TLD, and to simulate the wind-induced response of TLD structure system. The interaction model employed is a combination of the model which is based on the Boundary Element Method (BEM), for simulating the liquid motion in TLD container, and Multi Degrees of Freedom (MDOF) for structure. The numerical results are compared with experimental records and obserbations records. The validity of proposed TLD-structure interaction model is confilmed by the results of those comparisons. Furthermore, from the numerical simulations, the nonlinear effects by TLD which affected structure response and vibration characteristics are clarified.

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Based on Mindlin's plate theory, free vibration of rectangular plates with combinations of free and clamped edges is investigated by using the method of superimposition. For the Mindlin plate the boundary conditions on an edge x=constant are as follows : for clamped edge, w=θ_x=θ_y=0 : for free edge, M_x=M_<Xy>=Q_x=0. The rectangular plates under consideration are as follows ; plates with clamped three edges and other free ; plates with two adjacent clamped edges and others free. Eigenvalues of four digit accuracy are provided for a wide range of plate ratios, thickness to width ratios and modal shapes. Numerical results are compared with those of classical solutions.

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The purpose of this experimental study is to obtain basic data on snow load and management of snow on the roof of membrane structure. This experiment was done using the indoor model and the outdoor apparatus. We studied properties of the roof snow under various conditions. By experiments of the indoor model we investigated characteristics on the static sliding friction and the kinetic sliding friction. As a result, it became clear that the causes which give great influence on the sliding snow properties were temperature, snow quality and snow load. By the outdoor experiments we investigated these results using factors as the index.

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Shaking table tests are conducted to study dynamic soil-pile-structure interaction during soil liquefaction. The test results indicate that : (1) regardless of the rigidity of pile, the bending moment of the pile before liquefaction is significantly influenced by the deformation of the soil deposit ; (2) unless the pile is rigid enough, the bending moment of the pile is also influenced by the deformation of the soil deposit; and (3) the maximum bending moment of the pile is related better to the ground deformation than to the acceleration measured on the structure.

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A numerical method has been introduced to analyze ground vibrations due to impact pile driving operations. The proposed method consists of non-linear pile driving analysis of a hammerpile-soil system and linear analysis of three dimensionally propagating waves in multi-layered media. The field test was analyzed to verify the proposed method, as well as to investigate the influence of the reduction of soil resistance. Furthermore, the analysis was performed to study the features of ground vibrations generated by piles driven into the major types of soil deposits in Japanese urban areas.

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