This study focused to clarify the status of drying shrinkage in ready-mixed concrete via field study using simplified drying shrinkage testing method, which has not been sufficiently examined. The field study results revealed that significant variation in drying shrinkage properties for ready-mixed concrete. Furthermore, stochastic investigation for the field data demonstrated dominant influence of coarse aggregate type on drying shrinkage compared with other parameters like unit water content and led to establishing simple formula for predicting drying shrinkage. These results also inferred the risk in exaggerated expectation to restrict drying shrinkage only by selecting coarse aggregate type due to wide variety of drying shrinkage behavior among identical coarse aggregate type. Finally, mixing usage of multiple aggregate types was depicted effective via experiment to practically limit drying shrinkage.

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This research was done to establish the nondestructive testing methods for the evaluation of heat influences on a concrete structure received a fire-harm.
As nondestructive testing, the ultrasonic method, the rebound hammer method, the shore hardness method and the Mohs hardness method were used.
As a result, it was shown that almost of the nondestructive methods used were useful to evaluate heat influence on concrete by fire.

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In this research, reinforced concrete (RC) columns with ultra-high strength concrete were tested with regard to self-induced stress by autogenous shrinkage and temperature history. Parameters of experiment are reinforcement ratio, and temperature of fresh concrete. As a result, 1) ultra-high strength concrete containing silica fume exhibit temperature dependent autogenous shrinkage i.e. the higher peak temperature in early ages brings the larger autogenous shrinkage and the higher temperature of fresh concrete yields the smaller autogenous shrinkage, 2) surface crack was observed in a full scale RC column with reinforcement ratio of 3.3% placed in winter due to the larger autogenous shrinkage, 3) internal crack, which can not be observed from an outward appearance, was detected in the same specimen due to temperature dependent autogenous shrinkage, and this can be explained by the larger autogenous shrinkage at the center part of specimen than that in surrounding area. On the other hands, no such crack was seen in the same size specimen placed in summer.

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Accurate measurement of void ratio is essential for porous concrete, since its attractive performances are mainly determined by the continuous void. Measurement methods of air void ratio of porous concrete are prepared in the technical committee report of Japan Concrete Institute i.e. volumetric method and weighing method. In order to measure the void ratio of various types of porous concrete with wide range of aggregate size, however, it is sometimes difficult to apply them when a high accuracy is required. Especially, when small size aggregates are used for porous concrete, the error of measurement is not negligible because the amount of retained water in the pore during a measurement procedure is not expected to be very small. In the present study, in order to solve this problem, the authors have proposed a new method using an air meter, which realizes a clear separation of the sort of voids i.e. continuous, semicontinuous, and independent voids. Also, rather high accuracy can be expected and the required time for the measurement can be reasonably shortened.

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The effect of reinforcing fabrics to fatigue resistance of fluid-applied polyurethane membranes is described in the study. The membranes reinforced by the two kinds of reinforcing fabrics such as grass fiber and polyester fiber at various height in cross section were prepared. They were moved at three levels of movements of 0.5-1.0mm, 1.0-2.0mm, 2.5-5.0mm by the fatigue machine. It was made clear that the reinforcing fabrics improve the fatigue resistance of the membranes and the effect of them is noticeable for the membranes inserted at the lower position in cross section. It was also found out that fatigue resistance of the membranes is related to the property of reinforcing fabrics.

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The efficient evaluation method of slipperiness of pinpoint floors is proposed in this article.
Firstly, sensory test were carried out to make the sensory scales and the evaluation scales of slipperiness of pinpoint floors.
Then, the authors developed the slip meter of pinpoint floor (SMPF) to measure the slip resistance of pinpoint floors, the C.S.R·PF (Coefficient of Slip Resistance of Pinpoint Floors) can be expressed by the sensory scales of pinpoint floors. Finally, considering the relation between the evaluation scales and C.S.R·PF, authors presented the measurement and evaluation method of slipperiness of pinpoint floors.

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The information system by reading ruggedness with white cane is a stable method, because it is not influenced by surroundings of the noise etc. Moreover, it has possibility to inform only to the visually handicapped person. In this theses, a measurement method of vibration of the white cane was established. In this method, a device that imitates human operation of cane is used. And this theses also describes an indication method for degree of recognition of change of floor based on comparison with the measurement result of the vibration to results of sensory tests.

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Recently, the semi-active control method has attracted significant attention from many researchers and engineers. This method aims to minimize a structure's response by changing the damper capacity according to the state of the structure and the external loads, and various kinds of semi-active control algorithms have been proposed. A lot of them utilize mathematically difficult algorithms that require complicated computer systems. With these methods, we can not evaluate the effectiveness and overall safety of the system under various kinds of loads. One reason is that the behaviors of structures incorporating such complicated control systems can not be evaluated by conventional means such as equivalent viscous damping factor based on hysteresis. Therefore, a semi-active control system is wished in which the control effects can be easily quantified as with passive control systems. This paper describes the result of having proposed the simple quantification approach for the semi-active control effectiveness.

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A constitutive model of a high-hardness rubber in the small strain amplitude is constructed based on the stationary and non-stationary random vibration tests. The mechanical properties of the high-hardness rubber depend mainly on the strain amplitude, vibration frequency and temperature. Because the present high-hardness rubber has a smaller dependence on the vibration frequency and temperature compared to the ordinary visco-elastic materials, the dependence on the strain amplitude is considered mainly. The validity of the proposed constitutive model is investigated by the comparison with the results by the test.

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A generation method of broadband statistical Green's functions of horizontal and vertical ground motions is proposed. The method includs following new contents.
1. Near-filed and intermediate terms as well as the far filed term of the source spectra are considered.
2. The ratio of corner frequency of P-wave to that of S-wave is assumed to be the ratio of P-wave velocity to S-wave velocity.
3. Scattering effects are considered into the path spectra in the high-frequency range.
4. Site effects for vertical motions are represented by 1-D theoretical amplification factors assuming obliquely incidence P- and S-waves in the low-frequency range and vertical incidence P-wave in the high-frequency range.
The method is verified by comparison between the generated statistical Green's functions and near-field records during the 1998 Miyagiken-Nanbu earthquake with M_J=5.2.

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We have developed the anchorless retrofitting method of our previous research, and clarified the shear transmission mechanism in retrofitted frames. The strength of retrofitted frame without anchors is composed of the column punching shear strength, shear friction between the existing reinforced concrete girders and steel frame, and the column shear strength. In this paper, we considered the shear friction between the existing reinforced concrete girders and steel frame, and evaluated the shear friction as a coefficient multiplying the punching shear strength of the column. We performed FE analyses using concrete strength and span as parameters, and found that the ratio of the shear friction to story shear shared by steel brace is 0.35.. The method of evaluating the lateral strength of retrofitted frame without anchor was proposed, the average ratio of calculated values to experimental values was to be 1.33. We confirmed the safety of the proposed evaluation method.

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A static loading test was carried out on a two-bay two-story concrete encased steel (CES) frame in which the beams and columns consisted of only steel and fiber reinforced concrete (FRC). In this test, the structural behavior of the frame such as the failure modes, hysteresis characteristics and deformation capacity was examined. Although the frame designed to be a weak beam-strong column system with the flexural yielding at the both ends of beams and the bottom of the first story columns, the shear yielding in the joint panel of the interior beam-column joints also occurred. The results showed that the use of FRC in the CES frame controlled the damage of the concrete. In addition, the frame had stable hysteresis loops with almost no degradation in load carrying capacity until the average story drift angle of 0.05 rad. Static inelastic analysis with reversal loading was also conducted to simulate the story shear versus story drift response of the frame. It is shown that the analytical results agree well with the test results in this paper.

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The aim of the present paper is to present numerical procedures, using two types of FE methods, for the secondary and higher order bifurcations (tertiary and quarternary bifurcations) which appear after the first buckling of thin shell structures. With a limitation to a cylindrical shell under axial compression, the post-bifurcation behavior after the first bifurcation is analyzed precisely by considering modal coupling between several deformation modes of higher order harmonic wave numbers, and on all the way of post-bifurcation path the positive definiteness of incremental stiffness matrix of uncoupled modes is examined step by step to find if any higher order bifurcation or transcritical bifurcation appears. Based on the step-by-step examination, the higher order bifurcation points and the corresponding bifurcation modes are traced.

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Seismic response of raised domes with substructures are known to be very complicate, because of the roof having large numbers of parallel vibration modes, and their amplitude changing drastically along the relationship between domes and substructures. The authors have proposed simple method for estimating the response of such domes with amplification factors, however, they do not cover high-rise domes. In this paper, simple response evaluation method of lattice domes with high-rise proportions supported by various stiffness of substructures is proposed using continuous approach as the previous studies, and their validities are discussed against response spectrum analyses with CQC method.

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Generally in Japanese style rooms, sheathed walls with uncovered post have spread instead of mud walls. The sheathing material is nailed and inserted in the frame with noggings. The formula to calculate the elastic strength, yield point, ultimate strength and the ductility of factor has been derived for sheathed wall, considering the elements of the shear resistance of the nail struck in the noggings and frame, and the diagonal compression resistance of the sheathing material as truss action. In order to verify the formula, the shear examinations of sheathed walls have been carried out where five kinds of different sheathing material have been used. It is clear that the formula is sufficiently accurate to predict the elastic and plastic behavior of sheathed walls with uncovered post for structural calculation.

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Flatwize bending tests were conducted after a measurement of the visual grading factors and dynamic modulus of elasticity for a full scale rectangular-cut lumber sawed from Sugi (Cryptomeria japonica D.Don) mediumsize logs grown in Wakayama Prefecture. The purpose is to verify the applicability of machine stress grading of JAS (Japanese Agricultural Standards) and to examine utilization of the materials as structural lumber under flatwize bending. Main results are as follows. 1) As visual features rectangular-cut lumber whose ratio of knot size to face depth exceeded more than 60%, and which had dead knot showed brittle fracture. 2) Although visual stress grading and machine stress grading were both effective as stress grading system, the machine stress grading was more effective than the other. 3) Very strong linear relationships are observed between bending modulus of elasticity and dynamic modulus of elasticity. From these results in the above, the strong standard characteristic values of lumber by the machine stress grading using bending modulus of elasticity of the standard size of 45mm, were calculated. Therefore, the rectangular-cut lumber, of which quality is controlled by the present method, is available as structural lumber, since stiffness, strength, and ductility are guaranteed.

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The core plates of buckling-restrained braces are often required to yield at a small story deformation angle. Reducing the core plate cross-sectional area could decrease the yield strength, but this also decreases the axial stiffness. The use of a low-yield-point steel is limited due to limited variety. The yield strength can be decreased while maintaining its axial stiffness by reducing the core plate cross-sectional area and simultaneously increasing its end thickness. The adjustment of the yield strength and axial stiffness is also possible. In this paper, the effect of the yield strength and axial stiffness adjustment is examined using simplified calculation formulae. Tests are performed to verify the validity of the formulae. The energy absorption performance and failure mode characteristics are analyzed based on the test results.

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Anchor-bolt-yield-type exposed column-bases exhibit slip-type restoring force characteristics. The authors had proposed non-slip-type column-bases that use a wedge device to minimize slip. This paper clarifies the self-centering capability and cumulative damage response of a portal frame and a 4-story frame with non-slip-type and slip-type exposed column-bases by time-domain analysis. The results show that the residual story drifts and cumulative damage response of second-floor beams for frames with non-slip-type exposed column-bases are smaller than those of slip-type column-bases.

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In this study, an inelastic biaxial bending experiment in which a horizontal force is loaded in a direction at a certain angle to the principal axis of the section was carried out for H-shaped steel beam-columns each with a relatively small slenderness ratio having an inelastic energy absorption capacity. As the result of studies on the elasto-plastic behavior as well as on the analysis results, it was made clear that the maximum strength ratio (the ratio of the maximum moment to the full plastic moment), the ductility factor and the energy absorption capacity decrease with the change in the loading angle from 0°(strong axis bending load) to 90°(weak axis bending load).

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When a steel angle-section bar is bent about its weak axis, Brazier's flattening deformation should occur with the association of plate instability. When the angle is bent such that the free edges are in compression, torsional buckling is too predominant to keep the integrity. Thus, the interest is focused on the case that the free edges are in tension. In order to solve this problem, theoretical analysis on the basis of variational method and experimental test on thin-walled angle beams were done. It was observed that the waves of plate buckling are generated and developed, which obviously reduces the bending stiffness of the beam. However, the collapse is not governed by the plate buckling, but by either of flattening, ridge-line buckling and load-point crippling. When the collapse is governed by flattening, the moment vs curvature curve deviates significantly from the linear beam theory, but well coincides with the flattenig theory in consideration of the restraint due to limited span of experimental setup.

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Width-thickness ratio limitation of thin plate is defined in current standard by considering boundary condition and stress situation under either pure compression or pure shear. On one hand, considering the effect of bending force, the larger width-thickness ratio of thin plate is able to be used in many cases of H-shaped beams when overall buckling does not happen. On the other hand, overestimation may be caused in cases of light-gauge thin plates formed H-shaped beams with long span which are easily affected by overall buckling. This paper is to study the proper evaluation of limitation about width-thickness ratio of H-shaped beam members under bending and shear based on the coupled buckling analysis in previous studies by energy method, and an easy evaluation method is proposed.

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Shear friction between the steel base plate and base mortar contributes to the shear resistance of standard column bases. A value of 0.5 is adopted as the coefficient of shear friction in AIJ's design specifications, but the associated background data are limited. To investigate the dynamic shear resistance behavior between the base plate and mortar, a shake table study is undertaken using a large rigid mass supported by steel contact elements that rest on mortar surfaces fixed on the shake table. Horizontal input accelerations are considered for various magnitudes and frequencies. The results provide a constant friction coefficient during sliding with an average value of 0.78. Comparisons with previous test and numerical analysis are also carried out, and good correlation among them is noticed.

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We confirmed the mechanical behavior of unembedded type column bases subjected to variable axial and cyclic flexural load through the structural tests of two series. The structural tests of two series are composed of the experiment on the specimen of a real large size and the half reduction size. From the test result, it was shown that limit rotation angle of column bases subjected to variable axial loading decreases. The reason for this cause is that local bucking and fracturing of main reinforcement occurs at column bases subjected to cyclic flexural load under the variable axial load compared with column bases under the constant axial load. In addition, we carried out the elasto-plastic analysis, and verified the accuracy of the analysis.

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The stress change history of the 2000 Tottori-ken-seibu earthquake is determined using the strong motion records. The result shows large stress drop in the upper central part of the fault. Negative stress drop is observed at the NW and SE sides of the fault at the depth of between 5 and 10 km. The slip distributions agree with those obtained from kinematic models. The stress-time histories in the high stress drop zones show predominantly monotonic stress drop. The result indicates that relatively high peak velocities observed at the stations near the fault are due to the high stress drop and the directivity effect. The ground motion inferred from the obtained stress change shows high peak velocity around the source area.

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This paper presents a conjugate gradient method for the eigensolutions of large, sparse and symmetric matrices using Sylvester's law of inertia and the quadratic form. Since the proposed method is a PCG-based method, it is particularly effective when a sequence of either the smallest or largest eigensolutions of a large and sparse matrix are required. Moreover, the proposed method does not find unnecessary solutions, and it thus minimizes the required computational memory capacity. The proposed method is a method requiring only a relatively small computational time. The accuracy and stability of this method are confirmed by considering several numerical examples. The numerical results are of high accuracy even for the systems with multiple eigenvalues.

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