The tensile stress distribution model under bending, which consists of tensile behavior before crack, fiber pullout behavior after crack and tension-softening behavior, is proposed to compose an analytical model. The followings are concluded by analyses and experiments ; 1) Various tensile stress distribution models of previous studies are the special cases of the proposed model. 2) A reasonable agreement is observed between the model prediction and experimental data, supporting the validity of proposed model, except disagreement of bending strength for some cases. 3) The ductile bending behavior is observed, when the tensile strength is not excessively high compared to fiber pullout strength and which sustains until substantially high strain.

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The influence of high temperature curing in an early age on the strength development of concrete was indicated in this study. The strength development of concrete using high-early-strength portland cement strongly depends on the curing temperature at the time of 0-3 hours since concrete is mixed up. The strength development of concrete using low heat portland cement depends on the curing temperature at the time of 0-12 hours since concrete is mixed up. High temperature curing after 72 hours since concrete is mixed up accelerates the strength development of concrete using low heat portland cement.

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Building walls are finished in various ways. The surface of building wall seems to be a crucial factor to determine the impression of the building. This paper will clarify the evaluate process of the visual impression of the sprayed finishing. Bumpy finishing feels pleasant and bright colored finishing feels natural. These impressions are quantitatively evaluated by 1/f^n fluctuation modulus (=n) and lightness (=L^*) that are properties of sprayed finishing. If L^* ≧ 60 and n ≧ 2.1, sprayed surface feels pleasant and natural.

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Sounds generated from floors by various human actions (called the floor sounds) are usually recognized as noise. On the other hand, floor sounds may create an atomosphere of Noh play, dancing, sports, or effect as caution sounds for blind to perceive an obstacle and a person. In this study, a sensory test on the judgment of distance from the pronouncing source by hearing the floor sounds generated dealing with the newly developed pronouncing simulator was carried out. From the results of this study, it was confirmed that people could judge the distance between the pronouncing source and themselves. And it can be said conclusively that the judgment is made not only by the volume of floor sounds but also by the way of transmission of them.

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Many seismic codes in the world adopt a factor that is to reduce seismic design forces considering an energy absorbing capacity of a structure. The concept of the factor appeared in the SEAOC code as K factor. Now similar factors are included in many codes, e.g. R in U.S. and Ds in Japan. Though the concept of the factor is well recognized, the value varies much between countries. This is one of the largest differences between the seismic codes in the world. For example, for the most ductile structures, U.S. code reduces the design forces by the factor of 1/8=0.125, whereas Japanese code reduces the forces by the factor of 1/4=0.25. This paper discusses the background of the factor and to what extent the seismic forces can be reduced due to energy absorbing capacity.

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This report presents the result of LES calculation of turbulent flow around a 3-D prism (1 : 1 : 0.5 rectangular-prism) in a turbulent boundary layer at high Reynolds number. The inflow wind fluctuations conditioned by the experimental data were generated artificially. The problems by using artificially generated inflow was discussed and the applicability of this method was examined. The calculation results present that we can simulate the turbulent flow around a 3-D rectangular-prism accurately using the turbulent boundary layer for the inflow condition.

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In order to clarify the relation of soil-structure interaction effects and seismic damage on Hyogoken-Nanbu earthquake, nonlinear soil-structure interaction analyses are performed. The following results are obtained : 1) The input loss of earthquake motion is confirmed. 2) The response of base is nearly equal to that of the same depth of soil. 3) The soil-structure interaction effects decrease structure responses on low buildings.

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A finite element analysis method is proposed for predicting the steady-state limit of a cantilever beam-column whose cross-section is symmetrical with respect to two orthogonal axes in a 3D space. The beam-column is subjected to an idealized completely reversed tip-deflection cycling program with continuously increasing amplitude under a constant axial load. Firstly, an analysis method is presented for tracing the steady-state path of the beam-column. Secondly, the steady-state limit of a tip deflection amplitude is found as a limit point of a steady-state path. Finally, the steady-state limits are verified through finite element analyses of hysteretic responses of beam-columns.

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The purpose of this study is to make the reasonable estimation method taking the structural behaviors into account on the cast-in-place piles under seismic loading. As the stiffness and load carrying capacities of the piles are comparatively high, the interaction between the pile and its neighbor elements (i.e. ; pile-cap and ground beams) should be taken into consideration in order to grasp the seismic performance on the piles. In this report, at first, three one-third scale subassamblages, consisting of exterior column, cast-in-place pile and ground beam, were constructed and tested to investigate their seismic behaviors. According to the analysis of the test results, even under fluctuating axial loading in a pile, it was shown that the estimation method, which was proposed previously by the authors on deformation characteristics of the interior pile untill flexural yielding, was applicable. Additionally, the anchorage characteristics in the pile-cap of longitudinal reinforcing bars of pile and ground beam, the shear cracking strength of pile-cap and deformation characteristics of ground beam, which were also important matters to estimate the seismic performance of the piles, were discussed on.

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The damage to pile foundations of high-rise apartment buildings that tilted largely towards south in a liquefied area during the 1995 Hyogoken-Nambu earthquake is investigated. The buildings, designed and constructed in early 1980s, were supported on bored pre-cast concrete piles 500 mm in diameter and 26 m (13m+13m) long. An 8-m thick layer of reclaimed fill caps a marine deposit of Holocene soil which is underlain, at 24-m depth, by a stiff layer of Pleistocene sand having N-values greater than 40. The failure and deformation patterns of the piles above and below the excavated ground are observed directly and with a plumb bob, and with a borehole camera and an inclinometer both inserted into the hollow spaces of the piles, respectively. The pile heads are found to have been displaced westwards by 40 cm, with failures and cracks near the pile heads and around 10-m depth at all piles as well as with severe cutoffs at about 5-m depth except for the piles in the north row. The detected failure and deformation modes would be induced by the inertia force and ground displacement in the west direction, together with the southward ground movement that occurred on the southern part of the site.

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Seismic response of reactor buildings with torsional eccentricity should be investigated to increase flexibility of proportioning and arranging RC shear walls or weighted equipment in reactor buildings. For this, the seismic behavior of RC box-wall model structures was evaluated through static, pseudo-dynamic and shaking table tests. As a result, it was found that torsional eccentricity had little effect on ultimate strength in response, but demonstrated a considerable decrease in accumulated strain energy. Further, it should be pointed out that, in case of stiffness eccentricity, the stiffness degrading of the flange-wall due to tension caused a large shift of the center of stiffness to the loading direction, and that, incase of weight eccentricity, stiffness increasing by compression in the web-wall on the side of gravity center suppressed torsion. These characteristics should be taken into account to understand precisely the torsional behavior of such box-wall structures.

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Many works have been already published until today on the structural optimization of truss topology using the genetic algorithms. In most cases these works express the truss topology as a combination of members, and existence of each member is directly connected to the genetic code. These methods, however, have a fatal weak point. Namely when the topology is made along these methods, they might include needless members or those which lies on the other members. In addition to these problems, generated structures are not always given as a stable structure. These problems become more remarkable when the freedom of the problem becomes large. A new method is proposed in the present paper resolving those problems by expressing the truss topology as a combination of triangles which are joined each other. Detail of the proposed methodology is pre sented as well as the results of numerical examples which clearly show effectiveness and efficiency of the present method.

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The ductility of reinforced concrete beams in earthquake resistant frames is strongly affected by the magnitude of shear force. This is due to the degradation of shear capacity of plastic hinge regions in post yield range. The purpose of this study is to analyze the shear failure of beam plastic hinge in relation to the ductility ratio. Basic concept of the analysis is that the ductility of reinforced concrete beams decreases due to the degradation of aggregate interlocking and effective strength of concrete which comes from the increase of axial extension of beam plastic hinge region after flexural yielding. In the analysis, the truss mechanism was adopted where the condition of shear failure was given by the crushing of diagonally compressed concrete. The predicted ductility was compared with available experimental data and the better result than AIJ-A ductile design method was obtained.

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Few studies have ever been tried to make it clear whether torsional vibration gives any influence on earth-quake proofing of reactor buildings. In this paper, we propose an analysis model that can exactly chase the elasto-plastic behavior accompanied with torsional vibration. Namely, the two-dimensional macro-model that was proposed by Sakai for the dynamic elasto-plastic analysis, has been expanded into a three-dimensional macro-model to apply it to RC box-wall structures with torsional eccentricity. To identify the effectiveness of the model, the analytical results obtained by the proposed model are compared with the results of static and shaking table tests of RC box-wall model structures with torsional eccentricity, resulting in a good agreement.

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Recently, several high-rise RC buildings with a core wall have been designed and constructed. Due to demands of architectural planning, these core walls often become open section walls. Bending and shear loading tests and analyses were conducted for evaluating the structural capacities of the open section core walls. Major conclusions obtained from the tests and the analyses are as follows ; 1. In designing and analyzing the open section core walls, their loading directions must be taken into consideration since their structural behavior varies largely with the loading directions. 2. The test results can be well simulated by a fiber model bending analysis based on the linear strain assumption. 3. The lateral displacement which is calculated by a fiber model bending analysis, adding the shear displacement as well as the displacement caused by slip away from the foundation, can simulate the test results. 4. The ultimate bending strength for the core wall calculated by a fiber model analysis assuming the limitation of 0.3% concrete strain or 1.0% longitudinal rebar strain, can estimate conservatively the test results. 5. The required design ductility of the core wall can be obtained by confining the compression area concrete of a wall-column by lateral reinforcements. The required design curvature corresponding to the allowable lateral displacement, is assured by the proposed calculation method using a fiber model analysis. The results from this method can simulate conservatively the test results.

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In the previous studies, hysteretic performance of the damper of shear panel type using low-yield-strength (LYP) steel, which has about 100 N/mm^2 of yield strength, under static shear loading were verified through cyclic loading tests. Other strength types of steel also have been utilized for panel damper. In this study, three different strength types of steel : two types of LYP steel (LYP100, LYP235) and normal mild steel (SS400), are selected for shear panel of the damper. Six specimens of square panel, whose width-thickness ratios are 22, 33 and 50 respectively, were tested under static and cyclic shear loading without axial force. As the results of the test, specimens of lower strength type of steel that also had smaller yield strength ratio showed higher energy dissipating capacity. In consequence, it is understood that hysteretic performance of the panel damper with different strength type of steel, such as maximum strength, permissible deformation capacity and hysteresis rule, are well estimated by the empirical formula obtained from the previous studies on LYP100 steel panel dampers.

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Static loading tests were conducted on a through-column type RCS (reinforced concrete plus steel) structure. The portion surrounding its joint is composed of cover plate and FBP. The main study theme is the influence of beam eccentricity and bi-directional seismic force upon the joint behavior. The present research demonstrated the following : (1) specimens with eccentric beams have a smaller strength, and (2) the same design approach can be used for both directions ; besides, this paper evaluates : (3) the appropriateness of joint shear strength formula considering web panel opening ratio, and (4) the applicability of joint shear deformation model. The present study focuses upon the reinforced concrete column and steel beam (RCS) structure joints, composed of web panel with opening, face bearing plate, cover plate and triangle stiffener. In this reports, the authors et al., keeping in mind this experimental result, conducted loading tests on the interior beam-column joints.

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To investigate the ultimate behavior of high-strength concrete filled steel tube (CFT), dynamic loading test of CFT beam-columns has been carried out. The test results exhibit that the maximum strength of every specimen is larger enough than the ultimate strength predicted by the generalized superposed strength method but the ratio of them changes according to the relation between the strength of steel tube and filled concrete. It is also shown that there are two kinds of ultimate state which are the crack development in steel tube and the excessive accumulation of plastic axial deformation and special attention should be paid to the former ultimate state because it is brittle fracture in the case that CFT is filled with high-strength concrete and subjected to dynamic load.

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This paper is intended to study the combustion products of the thermal insulation materials, measuring the combustion products of the materials which were burned by a constant volume heat source of a steel ball. Properties were measured and analyzed about the composition of combustion gas,smoke density.smoke temperature and temperature above the surface of the thermal insulation materials. We discussed about the combustion products of the thermal insulation materials of several kinds of foams.

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Model fire experiments were conducted to characterize the effect of wind on flame properties in free boundaries. Propane gas was used as a fuel and 0.1m×0.1m diffusion burner was also employed as a model fire source. The effects of floor around a fire source, which would control the volume entrained into the hot current, were also investigated. The empirical models on the apparent flame height of the inclined flame were presented. We also deduced the empirical models on the flame tilt angle based on the balance of mass flux and/or forces, which are employed as governed variables for representing the upward hot current and wind. These models are represented by the simple formula with dimensionless heat release rate and Froude number. The calculated flame length based on the flame tilt angle and the apparent flame height was compared with experimental results, and which showed the models are applicable to estimate the flame length under the wind condition.

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