Domestic waste molten slag can be recycled into fine aggregate for concrete. The recycling process comprises heating, melting, cooling, solidification and secondary processing where influences of the furnace type at the heating and melting processes on the quality of molten slag and molten slag concrete are still unknown. We have studied the physical properties of molten slag obtained from furnaces of various type and behavior of molten slag concrete to clarify the effects of furnace type. Domestic waste molten slags generally met the quality requirements though it exhibited various characters according to the furnace type and the level of secondary processing. Also the molten slag concrete satisfied the specified quality when fine aggregates of domestic waste molten slag were used without regard to the furnace type.

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In the performance-based design for shrinkage cracking in building, the reliable mathematical model for predicting shrinkage and creep strain of concrete is required. It is desirable that the mathematical model is simple and accurate, and every engineer can use it without any difficulties. Then, in this paper, the prediction formula of shrinkage strain of concrete with a normal to high strength concrete was discussed using the test data published in the annual meeting of Architectural Institute of Japan. The proposed model was expressed as the product of two terms; one is the ultimate shrinkage strain that is expressed in terms of the product of three coefficients taking into account of mix proportions, age at drying and relative humidity, the other the time-effect function (the hyperbolic-power type) in which the effect of specimen size is concerned. Moreover, the effects of the kinds of cement, aggregate and admixture were introduced as the correction factors of ultimate shrinkage strain. It was found that the proposed prediction formula can estimate the shrinkage strain more accurately than the other formulas such as JSCE, CEB-FIP1990 and ACI209.

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From the viewpoint of the performance of floors, it is very important to construct floor groundworks with good quality. Good or bad of finishing work greatly influences quality of floor groundworks. However, such as high-strength concrete etc., difficulty of finishing work caused by the peculiar characteristic of concrete sometimes make problems. The purpose of this research is to establish the method of indicating workability for floor groundworks. In this thesis, first of all, easyness of troweling was examined. Then, combining easiness of leveling established in the previous thesis, the indicating method of workability for floor groundworks was set.

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Generally, there are many corners with right angle in buildings. From a viewpoint of safety and comfort, those right angle corners affect human movement, such as the easiness for walking and visibility, wheelchair mobility. In this study, we considered the safety in sorts of corners, while cornering. After consisting of the scales of easiness for walking and visibility, wheelchair mobility, we considered that the relationship between two types of corners and safety. Conclusions of this study are as follows. The corner with a corner cut is safer than right angle corner. Evident effective lengths of corner cut is longer than 50cm〜75cm.

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Requirement of long-term use of existing buildings has been increasing in aspect of environmental and economical issues, and the visual impression of building materials from the view point of aesthetics is considered as an important factor for long-term use of buildings. In this research, the new methodology by using 2dimensional Fourier Transformation has been developed for evaluation of stains on exposed concrete surfaces. As a result, various shapes of stains on the constant distance have been explained by the slope of power spectra by frequencies which make up a digital image including stains.

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Requirement of long-term use of existing buildings has been increasing in aspect of environmental and economical issues, and the visual impression from the view of building materials is considered as an important factor for long-term use of buildings. In this research, new methodology by using 2dimensional Fourier Transform is developed for evaluation of visual changes on exposed concrete finishing. As a result, mechanism of phenomena that the view of building materials changes depending on the observation distance could be explained by frequencies comprehensively.

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This paper describes the design seismic coefficient (DSC) of the embedding foundation of building structures, which is required for the design of foundations such as basements and pile foundations. In the current Building Standard Law (BSL) of Japan, DSC is empirically specified as one-half of the base shear coefficient of a superstructure. However, the seismic design requirements in the BSL were revised in June 2000 to a performance-based design framework. A new seismic design method called the "response and limit strength calculation"(RLSC), which incorporates the effect of the soil-structure interaction, was developed. In the BSL revision, however, DSC is not referred to and must be evaluated by the conventional method mentioned above. Applying the numerical procedures employed in the development of RLSC, a practical evaluation method of DSC is investigated. A regressive formula is derived from the DSC and the ratio of the embedded depth to the foundation width.

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This paper presents a performance evaluation method for passive control systems with viscous damper expressed by Maxwell models. It is very difficult to estimate simply the maximum seismic response value by cause of the system property of frequency-dependency. In this study, eigen value problems with complex numbers are analyzed for the system, so as to investigate the dynamic characteristics. Generally, a single mass-spring system with Maxwell model has three degrees of freedom. That is, the three eigen values are derived, in which the two are conjugate complex numbers λ_1 and λ_1^^-, and the other is real number λ_1'. And the multiplication between the conjugate complex numbers makes the square value of natural circular frequency ω and the sum of them derives the value of -2hω, in which the variable h means the viscous damping factor. For convenient, the eigen value of real number is replaced by the value h_Mω. The result shows that Maxwell model and Voigt model have the same natural period and viscous damping factor for the case that the value h_M becomes bigger than unity. In addition to this, an empirical formula with those parameters h, ω and h_M is proposed in order to estimate the maximum seismic response values of the system.

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In this paper, the topology optimization method of link mechanisms is shown. In the link mechanisms composed of rigid bodies and hinges, the displacement of the output point can be controlled by the load of the input point. In the present method, the ground structure composed of beams is used in order to obtain the optimum topology of the link mechanisms. In the optimization problem, the sectional areas of the beams are chosen as design variables. The stiffness between the input point and the output point is maximized under the constraints of the displacement of the output point, the relativity displacement of the output point and input point, and the material usage. The optimization problem with different initial design variables are solved using the SLP optimizer, because the solution of this problem depends on the initial design variables. The initial design variables are given by random numbers or GA. Some examples are shown to demonstrate the effectiveness of the present method.

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Recent spatial structures such as shells and space frames become so large in spatial span that upon an external force local damage may occur first before the vibration state of the whole structures. It is thus important to investigate and estimate dynamic behaviors of spatial structures from a viewpoint of wave propagation. The impact hammer experiments for three lattice-type plates and one continuum plate are performed and the wave propagation properties such as propagating velocities, damping, etc. are discussed in the present paper. Preliminary experiments which were performed in advance for evaluating effects of boundary conditions are also presented.

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Existence self-equilibrated stress states and inextentional displacement modes largely dominates fundamental structural properties of Tensegrity. Finding appropriate bases for the self-stress states and displacement modes of tensegrities is useful and helpful in understanding and examining their structural behavior. In the paper we apply the group theoretic approach in extracting the sets of bases of self-equilibrated stress states and inextentional displacement modes of tensegrity structures. Block diagonalization of orthogonal projectors onto vector spaces defined by equilibrium matrices is formulated. Examples of bases of self-equilibrium states and inextentional displacement modes, based on the irreducible representations, for some tensegrity models are shown.

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The present paper discusses possibility of a steel cooling tower with buckling-restrained members installed at the feet to effectively reduce seismic response. First, buckling behavior under wind and dead loads is investigated using elasto-plastic analysis, followed by a study for the seismic response based on eigenvalue analysis and elasto-plastic time series response analysis. Second, the effectiveness of the buckling-restrained members is discussed for reducing the seismic response of a steel cooling tower and keeping the stresses of steel members lower than yield stresses under strong earthquakes. Finally, a possibility of steel cooling tower is shown as a conclusion that the design forces of the cooling towers against earthquakes will be lowered on account of the buckling-restrained members, leading to relatively low construction cost with a high structural reliability.

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In this paper, girders with wall having seismic slits were modeled and a two-dimensional static elasto-plastic finite element analysis was performed. The parameters were girder section, span, main bar, concrete strength, slit wide and wall thickness. 111 models were analyzed. Key observations include the followings:(1) The stiffness K and α_y・K of girder with wall having seismic slit was large.(2) The effect of slit wide for the relationship between shear and relative displacement was small.(3) The effect of wall thickness for the elastic and plastic increasing ratio was small.(4) The effect of concrete strength for the elastic and plastic increasing ratio was small.(5) The elastic and plastic increasing ratio was derived by using the equations (9) and (10).

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The primary purpose of this study is to clear the effect of constraints across the crack surface due to the reinforcements upon the mechanism of shear transfers and shear crack behaviors in a cracked concrete. The confining pressure is estimated from assumed reinforcements, and automatically applied on crack surfaces by a closed-loop servo system. The test results show that the shear behaviors in cracks are deeply affected by reinforcement ratio (confining stiffness) as well as reinforcement strength (confining pressure). The relations of normal and shear stresses to crack opening and shear displacements have been investigated on the basis of normal constraints across the cracks. The FEM analyses have been also carried out to verify the shear transfer models in cracks by comparing with the test results on specimens containing a fracture process zone that the tensile stress can still be transferred.

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A three-story R/C school building suffered severe damages during the 1994 Sanriku Haruka-Oki Earthquake. Most first-story columns failed in shear while second- and third-story members remained nearly intact. Nonlinear frame analysis was conducted to reproduce the observed damages to this building, where the load-deflection relations of columns including post-peak region were determined based on test results. The analysis was found to reproduce the observed damages. The beams above the second floor level were computed to have once yielded but have been unloaded after shear failure of the first-story columns. The unloading of the beams that resulted from the decrease of each story shear following the deterioration of the first-story column strength was the reason of their observed slight damage.

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In this study, cyclic behavior of joint panel in H-shaped column to beam connections is cleared, and modeled using by Menegotto-Pint model. Parameter is the ratio of joint panel strength to column or beam strength. In order to clear that, loading test and numerical analysis is carried out. First, skeleton curve modeled by using results of analysis and loading tests. Secondary, the effect of experienced displacement and Bauschinger's effect are investigated, so cyclic behavior of joint panel is modeled. The effects of axial force, frame shapes and the frame around the joint panel to the behavior of joint panel is cleared.

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Predictors or estimates of seismic structural demands, such as inter-story drift angles, that are less time-consuming than nonlinear dynamic analysis can be useful for structural performance assessment and for design. The authors have proposed a predictor using the SRSS rule of modal composition, and taking into account a first-mode inelastic spectral displacement and a post-elastic first-mode shape approximated by the distribution of the story drifts obtained through a nonlinear static pushover analysis. This paper statistically investigates the dependence of the accuracy of the predictor on the lateral force distribution in the static pushover analysis and the backbone curve of an equivalent SDOF system using frame models with various stiffness distributions.

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A new type of seismic beam-end splice is proposed which uses a hysteretic damper as the splice element at the bottom flange of the beam. The design intent of this beam-end splice is to concentrate plastic deformation of the beam to a replaceable damper-and-splice element while limiting damage to the concrete slab. Non-degrading hysteretic characteristics of the damper-and-splice element is achieved by adequate buckling restraints. Based on axial loading tests of the damper-and-splice element and simple mechanics, design equation for the buckling restraints were established. Beam-column subassemblages implementing the proposed beam-end splice exhibited excellent cyclic loading behavior. Concerns regarding web crippling of the beam directly below the top flange splice are addressed.

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The authors evaluated the frequency response of ground motion based on self-affine fractal. The fractal dimension of ground motion with high frequency indicated over 1.7. And the ground motion with low frequency indicated around 1.5. The authors calculated the fractal dimension of ground motions observed in all over the Japan for totally 3438 records, then drew the contour chart by Kriging, and investigated the geographical distribution of the fractal dimension.

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To understand site effects within Hiroshima prefecture, predominant periods of the ground in the linear condition and during the 2001 Geiyo earthquake were estimated from microtremors and seismic motion at site of K-NET, KiK-net and Seismic Intensity Information Network. Conclusions were obtained as follows:(1) the H/V spectra were able to estimate the predominant period of the ground stably,(2) although predominant periods at most sites were shorter than 0.4s, those at several sites in sedimentary basins in southern region were longer than 0.6s, and (3) strong nonlinear behavior of the ground occurred at many sites during the main shock.

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