Modeling fresh concrete's rheological behaviors is basically needed for flow simulation and establishing indexes of quality control and test method, which are indispensable to workability design of concrete. In this study, the author proposed a microscopic approach to rheological performance clarification of fresh concrete based on a series of past studies on viscosity mechanism, granular characteristic, shear resistance-particle fabric relationship, shear deformation-particle movement, etc. This approach treats with fresh concrete as a kind of particle assembly containing water, of which deformation resulted from particles' movement can be induced following by analyzing the probability of moving particles, and variation of mean particle contact angle and distance of particles. Using this approach, constitutive laws of fresh concrete before and after yielded were investigated theoretically. The obtained constitutive laws are applied to not only high fluidity concrete but also stiff concrete, and can express the characteristics of shear deformation/flow of fresh concrete: non-linear, and vertical pressure, stress history, and loading elapsed time-dependent.

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In this study, the investigation to find out the evaluation index of drying shrinkage strain of aggregate was carried out. The following findings were obtained as the results. (1) Air-dried moisture content and specific surface area of fine and coarse aggregates, direct measurements of drying shrinkage strain of coarse aggregate etc. correlate highly with the drying shrinkage strain of law stone of aggregate. Therefore, these values can be used as the evaluation index of drying shrinkage strain of aggregate. (2) Some aggregates not corresponding well to drying shrinkage of aggregate are invariably to be found in case of all evaluation indexes. Consequently this fact should be taken into consideration in estimating the drying shrinkage strain of aggregate. (3) The drying shrinkage strain of aggregate has a direct effect on that of concrete.

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Recent development of techniques on computational fluid engineering has enabled us to simulate the complicated flow around buildings. Large Eddy Simulation (LES) is expected to be adopted as an effective technique to evaluate wind load on buildings for wind-resistant design. In this paper, focusing on unstructured grid system, which is effective in terms of adaptability to configuration and flexibility to element size density, the availability of LES to evaluate surface pressures on the 3D square cylinder model is examined. The computed results correlate highly with the experiments, and applicability of this method is presented for wind-resistant design of buildings.

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It is important to maintain functions of a building such as providing medical services, performing production operations, and dwelling during and after an earthquake. Until now, vibration control devices have been devised and installed in many buildings. To maximize the control effects under the limited capacity of a control force, a method for constructing an evaluation function on the basis of the prescribed control objectives is proposed, in which the control objectives are expressed as dimensionless numbers using the required performance levels. The effectiveness of the proposed method is verified by a time-history analysis.

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When making repairs to buildings affected by earthquakes, restoration by just adding strength is commonly used. However, this causes a large change in the axial force on the piles because of the increase in the overturning moment. In this paper, when applying seismic retrofit by using a device with hardening type hysteresis, it was revealed that the increase in overturning moment could be controlled and the maximum ductility factor could be reduced. Furthermore, we proposed a prediction formula for the maximum ductility factor when there is a weak story in the building.

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The present paper discusses the active vibration control of arch structures. In previous paper discussing the active vibration control tests, it is difficult to reduce the seismic response because of the excess of delay time. Overcoming this difficulty, this paper deals with the active vibration control on the optimal control theory with the modal control so that the delay time decreases and the seismic response control should be possible. First, we explain the control theory applying the modal control method. Next, for demonstration, the active vibration control tests of the arch structures are carried out. Moreover, the response and control force evaluations are examined by numerical analyses. Finally, the optimum arrangement of actuators is discussed. The Optimization method by response and control force evaluated by the response spectrum method with transfer function is suggested. Then, the optimization is carried out for a plane reticulated arch.

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In this paper, the genetic algorithm with immune system (ISGA) to obtain the decent solutions is applied to the structural morphogenesis for a free-form grid shell. The decent solutions have comparatively high evaluations. These solutions contain a global optimal solution and local optimal solutions, and maintain the diversity of the design variable space. The use of the decent solutions satisfies a structural rationality, and enriches the designer's ideas about various structural forms and systems.
In general, when the structural morphogenesis concerning a curved surface structure is treated, to represent a smooth curved surface and to decrease the unknown number the parametric surface is adopted. However, the parametric surface has the possibility to give influencing for the form of the obtained solutions. Here, NURBS that the degrees-of-freedom of the shape representation is high is adopted as the parametric surface, and the relation between a decent solution form and the order of NURBS is examined. When the structural morphogenesis for a free-form grid shell is treated, the knowledge on the numerical analysis using NURBS is indicated from the numerical results.

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Displacement mode including torsion in ultimate state is clearly related to strength balance of each frame while elastic torsional vibration is characterized by stiffness balance. Therefore, this paper presents displacement mode prediction method especially focusing on timber structure having large strength eccentricity. The method also considers variability of response due to earthquake characteristics. Finally, seismic performance index of torsionally coupled structure which indicates necessary additional strength is formulated by calculating potential energy of each shear wall until ultimate state. The accuracy of the evaluation method is demonstrated via numerous time history analyses and shaking table test.

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Tensile Performance of Cross Laminated Timber joints composed with a single drift pin and steel plate were studied. Different end and edge distances and diameters of the drift pin were set as parameters. Characteristic values were obtained by tensile tests. The yield load was estimated by modified EYT. The characteristic features of CLT drift pin joint observed in the test were as follows; (a) Cross layers work to prevent the split failure along the grain from the drift pin. (b) There is linear relationship between maximum load multiplied by distance at maximum load and end distance multiplied by edge distance.

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In this paper, a method to evaluate the cumulative ductility till fracture in steel members subjected to random amplitude loading is presented. The method predicts fracture when the damage variable, evaluated through a combination of Manson-Coffin's law and Miner's rule, equals unity. The effect of mean plastic deformation is taken into account through the method of Sachs and Weiss and the underestimation of Miner's rule in evaluating damage of loading histories which include relatively small amplitudes is remedied by a modification of the loading history through separation of cycles. The proposed method is verified with experimental data from steel members with various material, geometry, and mode of fracture (ductile, brittle, pseudo-brittle). The relative error in the predicted cumulative ductility till fracture in most of the specimens is within 25%.

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A design procedure is proposed for estimating the required thickness of wood panels used to stiffen the slitted steel shear wall. Setting a value for the ratio of modified buckling strength, which is obtained by assuming the effect of stiffening as an increase in bending rigidity, relative to the yield strength, design formulas for thickness required for the stiffening panel is derived. The design formulas allow for the effect of the number of bolts and the overall dimension of the wall as well. These formulas are found reasonable by the comparison with the associated experimental and numerical results.

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In this paper, the static behavior of three dimensional cruciform structure using STKR column is investigated by the loading test. Parameters are the loading direction and the reinforced parts, an original specimen is not satisfied with the specification of column overdesign factor in the current seismic code. Test results show that the damage of each member of the original specimen is different by the loading direction, the column collapse easily occurs in case of 45 degree directional input. In case that the column is reinforced, the column collapse is prevented regardless on whether the panel is reinforced.

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This paper summarizes the results of static loading tests conducted for a full-scale, four-storied frame structure. The structure was composed of high-strength steel, H-SA700, and designed based on the separately proposed performance-based method intending damage-free structures even under extreme earthquakes. Loading history, in a form of enforced displacement at each story, was determined through response analyses. Test results showed that the structure would remain elastic under earthquakes of JMA seismic intensity 7, indicating the adequacy of the design method. Reusability of the structural components was also confirmed by visual and dimensional checking.

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Authors are developing steel concrete structure buildings as a new structural system to take the place of the steel encased reinforced concrete structure to which the number constructed in recent years has decreased. It has already been clarified that seismic performance of column of this structural system is excellent. Next, it works on the development of exposed type column base of this structural system. Exposed type column base is advantageous for the workability and the economy. In this paper, it is discussed about the mechanical behavior of column bases through the structural tests under the axial load and the cyclic horizontal load. The experimental parameters were as follows, axial load level and method of connecting the column to the footing beam. The structural tests make it clear that ultimate flexural strength can be evaluated to superposed strength method. Moreover, proposed evaluation method of restoring force characteristics matches the test result well.

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