Main purpose of the present study is to examine the rising behavior (bleeding) of free water in mortar by using a proposed visible evaluation method. A series of experiments of exp.1 to 3 was carried out. In exp.1, rising path of colored liquid as free water injected into mortar was observed. In exp.2, effect of water-cement ratio and volume of the injected colored liquid on its rising distance was examined, and the behavior of the internal bleeding water was idealized for modelling. In exp.3, applicability of the proposed model was verified through a 2-dimensional visualization experiment, using model materials. Consequently, it was shown by the devised visible evaluation method that the bleeding behavior in mortar can be checked qualitatively. Moreover, the rising process of the colored free water showed clearly that the proposed method is applicable to discuss the bleeding behavior in actual mortar and concrete.

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Drying shrinkage of concrete exerts a serious influence toward the long-term reliability such as the durability of the structure. The estimation formula of drying shrinkage of concrete is necessary by using examine this behavior of properties. In this paper, the prediction estimation formula of drying shrinkage strain of concrete is obtained with two-phase composite material model as cement paste and aggregate. The results of the this study are summarized as follows: 1) The elastic modulus of cement paste can be explained as a function of the cement-water ratio and age at drying, as well as drying shrinkage strain. 2) Drying shrinkage of aggregate can be explained as a function of its absorption. 3) Drying shrinkage of concrete can be calculated using five parameters of water-cement ratio, age at drying, the absorption of aggregate, the volume of aggregate and volume-surface ratio of member. The calculated results agreed well with the experimental data.

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The relationship between pozzolanic reaction and strength development of cement paste and mortar with fly ash are investigated. By measuring the consumption of Ca(OH)_2 in cement paste using fly ash, the different pozzolanic reaction rates in different mixture proportions with several admixture rate or different type of Portland cement are calculated. After analyzing the strength development of mortar using fly ash, we conclude that it could be regarded as a sum of strength development of mortar without fly ash, strength increase owing to pozzolanic reaction of fly ash and powder effect. As a result, the strength development of mortar using fly ash is expressed by estimating equation proposed in this study.

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The object of this paper is to propose an equation for predicting compressive strength of porous concrete. The factors influencing mainly the compressive strength of porous concrete were picked out. The proposed equation was constituted with the following three factors; void ratio, water cement ratio and oven-dry density of coarse aggregate. It is found that the 28-day compressive strength of porous concrete can be estimated by using the proposed equation. However, the influence of the type of cement was not clarified because its limited data.

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This paper discusses equivalent static wind load that reproduces the maximum load effect on structural members. Current methods for estimating equivalent static wind load are mainly aimed at a certain load effect on a structural member or wind force. In practical design, innumerable maximum load effects can be considered. Therefore, strictly speaking, innumerable equivalent static wind loads also have to be considered for each of these load effects. In this study, the equivalent static wind load that reproduces maximum load effects is shown by a combination of the eigen modes calculated by POD analysis to the fluctuating wind pressure. Applying a singular value decomposition to a matrix of eigen modes by the influence function optimizes the equivalent static wind load combination. This method is applied to large cantilevered roof models. The maximum load effects for bending moment and shear force are focused to estimate the equivalent static wind load. The solution shows the equivalent static wind load that simultaneously reproduces both maximum shear force and maximum bending moment for all structural members.

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We try to identify the stiffness of a base-isolation layer for a large-scale base-isolated structure in Fukuoka. Our method is based on the fact that the natural frequency of a structure will be modified by certain amount when we increase the mass of that structure. If we know a-priori the amount of added mass, then we can invert both the stiffness and the original mass at the same time. We applied the method for the multiple frequency data of a base-isolated building obtained through microtremors during construction period. Since the level of microtremors is on the order of micron, the resultant stiffness will be those for microscopic loading. The stiffness of the base-isolation layer that we inverted is unanimously higher than the value used for design, about three times. To explain the difference we use the same technique to obtain the real stiffness of rubber bearings. We found that they are about twice as large as that used for design. Based on these two facts we deduced that lead dampers should have five times larger stiffness, provided that the hysteretic steel dampers would not show any strong strain dependency.

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In this paper, a generation method of simulated earthquake ground motion for the structural design of buildings is proposed. In the method, the Fourier amplitude is prescribed by the ω-square model and the Fourier phase is selected from the observed data, based on the standard deviation of the phase difference, in which the source and propagation characteristics of seismic waves are reflected. Since the Fourier amplitude and phase are independently dealt with, these properties can be logically determined based on the source and propagation characteristics of seismic waves. The features of the time history and response spectrum can also be clearly explained in terms of these properties. The proposed method is useful because it can be applied to both inter-plate and crustal earthquakes, and is rational because the simulations are validated by comparison with observed earthquake ground motion.

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This paper shows a method of setting soil parameters of FEM analysis in order to predict relationship between pile end load and settlement. The accuracy of the prediction depends on which constitutive equation to be used and the parameter values to be set. Generally it is difficult to set all the parameters properly because the given information is usually only STP N value and overburden pressure. The author proposes to use an approximate constitutive equation to overcome the difficulty and how to set the parameter values. An example is demonstrated in case of bored piles.

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This paper presents an easy-to-use two-dimensional calculation method for a cylindrical-shape cantilever earth retaining structure, as affected by the three external factors, they are: the lateral pressures, mean wall temperatures, and differential temperatures. In this method, the results are obtained by superposing the individual solutions due to the three external factors, as above. Correction for their mutual interaction is then introduced in terms of the subgrade reaction of soil. The authors compare behaviors of the said retaining structure calculated (a) by the two-dimensional calculation method, and (b) by the conventional three-dimensional FEM analysis. Their satisfactory agreement proves usefulness of the present two-dimensional calculation method.

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The authors have proposed the concept of ductile truss structures replacing critical members to buckling-restrained braces. However, in case of seismic retrofit for existing truss structures, effective buckling restrain method for existing members are required. In this paper, buckling restrain retrofit method using outer-tube and in-filled mortal in-between is proposed, and tested under elasto-plastic compression conditions. Their performances are compared with tubes without restrainer or mortal in-filled tube, and their buckling behaviors are studied by numerical analyses.

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Evaluation (screening) of the seismic performance of RC buildings has been widely carried out in various ways mainly based on the manual issued by Japan Disaster Prevention Association. According to results of the evaluation to date, failure mode of aseismic walls are apt to be estimated as "rotation", in spite of the fact that such failure mode has been hardly recognized in the past disasters, except for the case of collapses due to uneven settlement or liquifation of ground. In the present study, firstly the resisting mechanism of a structure against rotating internal walls is analysed, using the result by "the 3^<rd>-step aseismic evaluation method" for a typical old building of 3 stories. Secondly, the effect of foundation piles on the rotation bearing capacity of seismic walls is discussed. As a result, it is pointed out that the main factors affecting the bearing capacity are resisting forces due to dead load, coupling beams, transverse walls, and foundation piles. In order to change the failure mode of rotation into another one (bending or shear), however, combination of two or more resisting forces due to the above such factors is required.

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Recently, mechanical anchorages are frequently used for high-strength and thick reinforcements because of congestion of reinforcements in beam-column joint. Many researchers have aggressively studied on the anchorage strength of beam reinforcement and the ultimate strength of R/C exterior beam-column joint, however, these structural performances could not be evaluated for various sorts of mechanical anchorages. In this paper, the authors propose the evaluation method of the anchorage strength of beam reinforcement on the basis of past experimental studies. Consequently, the authors clarify the design criteria on the ultimate strength of R/C exterior beam-column joint to ensure the ductility at the beam end.

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Recently, mechanical anchorages are frequently used for high-strength and thick reinforcements in R/C exterior beam-column joints at middle stories. However, the design criteria on the ultimate strength of R/C T-shaped and L-shaped beam-column joints at top story is not clarified, because the stress condition of these joints is complicated in relation to the detailing of reinforcements. In this paper, the authors propose the evaluation formulas of the ultimate shear force of beam-column joint which is transmitted through the ultimate end moment of beam or column. Consequently, the authors clarify the design criteria on the ultimate strength of T-shaped and L-shaped R/C beam-column joint to ensure the ductility at beam end or column end, on the basis of comparison between design values and tested values of past experimental studies.

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This paper describes estimation of load-deformation characteristics concerning precast prestressed concrete flexural members, in which a combination of unbonded post-tensioned (PT) reinforcements and bonded deformed bar reinforcements are used. The unbonded PT reinforcements are designed not to yield during seismic excitations, so as not to decrease a self-centering force. On the other hand, the bonded deformed bar reinforcements are intentionally designed to yield for energy dissipation. In order to estimate the load-deformation characteristics and material strains of the members simultaneously, a newly developed macro model that reflects behavior of the plastic hinge zone of the members is applied and compared with test results. By the comparison, the macro model is verified to have enough accuracy for practical use.

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After the Hyogoken-Nanbu earthquake, building which used damper as an earthquake resistant member is increasing. The damper is used for not only new construction but also seismic repair. In case of seismic repair, strength eccentricity or stiffness eccentricity may occur in damper system by the constraint of floor planning. It become an important problem to evaluate the effect of the eccentricity in damper system on earthquake performance of building structures. In this study, in order to clarify this problem experimentally, a series of full-scale shaking table test of single story steel frame is carried out. Main parameter in this experiment is strength eccentricity and stiffness eccentricity in damper system. The experimental result showed good correspondence with the result of response analysis using the fundamental model. Therefore, it was proven that this problem could evaluate in analytical approach.

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The brace installed in frame has various boundary conditions, for example, simple supported, fixed or semirigid end ,at both ends. This paper evaluates the strength of H-shaped brace constrained flexural buckling, taking these boundary conditions into consideration. Boundary conditions were considered as rotational rigidity and strength was evaluated about three failure modes, respectively. And the propriety of it was verified by structural experiments. By this evaluation, the rotational rigidity which can be regarded as a simple supported end or a fixed end had been grasped. Moreover, one example of the rotational rigidity evaluation about actual structure details was shown.

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We formulate a stability design procedure for plane steel frames subject to combination of vertical and earthquake loadings. The formulation is an extension of the basic framework for stability design using the linearized buckling analysis presented in Part 1 of this paper. Interaction of axial force and bending moment is taken into account, which is not negligible in the case of the combined loadings. In the numerical example, a braced frame with a slender column is designed in accordance with the current design code and the proposed method. Comparison of the design results demonstrate the possibility of reducing member sizes by the use of the present method. We also show the validity of the estimate of the inelastic buckling load obtained by the present approach by comparing it with the buckling load computed by the finite element method.

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An experimental study on real scaled one-bay-one-story frames with transverse walls in precast reinforced concrete housing of low-rise wall-building system was carried out to examine the effect of the transverse walls on the structural performance of the housing. An outline of the testing is described and the shear resistant mechanisms of the transverse walls are examined based on the test results in this paper. The conclusions obtained are; (1) The transverse wall effect is effectively developed in the frame. (2) Strength induced by the transverse wall effect can be estimated as the minimum value among the followings: a) direct shear of the floor rib at the top of wall panel, b) punching shear of the floor rib at the top of the transverse walls, and c) tension of joint bolts at the top of the transverse walls. (3) Relationship between the horizontal displacement of the frame and the transverse wall effect can be evaluated by bi-linear skeleton curves.

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A building that is composed of coupled shear walls with dampers, CFT columns, and flat plate slabs is one of the types of buildings that can be reused, with low repair cost, after an earthquake. To evaluate the lateral load-deflection relation of the newly designed CFT column/flat plate connection, two series of experimental studies were carried out: lateral loading tests for interior column/slab connections, and element tests for torsional stiffness and strength. Lateral load-deflection behavior of the CFT column/flat plate connection were examined using macro models proposed in this study, and good agreements are obtained.

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