This research is able to develop the artificial light-weight aggregate made from a coal ash and a shale fine powder as main raw materials, and use a large amount of coal ash effectively as an aggregate for concrete. As a result, this newly developed aggregate can be manufactured by using existing facility for a sintered shale light-weight aggregate, and it can be confirmed that it was an high-performance aggregate which maintained lightness, high strength, and high water retentivity and harder composition compared with several existing and marketing light-weight aggregates. Moreover, this aggregate obtained the various physical properties by changing the compounding ratio of the raw material of two elements.

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This study is aimed to elucidate the influence of ambient relative humidity on the compressive strength of fly ash cement paste. The ambient relative humidity has an influence on both the internal relative humidity and the hydration reaction, and further influences the compressive strength development. The experiment results revealed that the compressive strength of paste decreases with a reduction in ambient relative humidity. The same tendency can be found on the internal relative humidity and the hydration reaction as well. The detriment of strength development at low ambient relative humidity is affected by the retardation of the hydration reaction of C₂S and C₄AF. Moreover, the internal relative humidity at the time of test also has an influence on the compressive strength. The compressive strength decreased with the reduction in the relative humidity below the relative humidity lower than 95%. In addition, the compressive strength can be expressed as a function of the internal relative humidity and the hydrated gel volume derived from the degree of hydration of cement and the degree of pozzolanic reaction of fly ash.

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Recently, increasing various constructions, we can choose various cement for each concrete constructions, suited their performance. We studied properties and time interval for placing on consolidated fresh concrete with fresh concrete with ordinary portland cement, moderate-heat portland cement, portland blast-furnace slag cement, portland fly ash-cement, and eco-cement. And we prepared influence of the durability of placing joint. The results suggested, ordinary portland cement had high compressive strength and eco-cement had less bleeding water. Additionally, the results showed the time interval of placing influenced the termination time of bleeding with various cements.

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This paper deals with the reaction to the fire tests of polymer-modified mortars, which are performed according to ISO 5660 and ISO 1182. Polymer-modified mortars using a styrene-butadiene rubber (SBR) latex, poly(ethylene-vinyl acetate)(EVA) and polyacrylic ester (PAE) emulsions are prepared with polymer-cement ratios of 0, 5, 10, 15 and 20%, and tested for fire-protecting performance in accordance with ISO 5660 and ISO 1182. As a result, all the polymer-modified mortars with polymer-cement ratios of 5 and 10% are acceptable as noncombustible materials. Gradings for fire-preventive materials by both ISO 5660 and ISO 1182 tests of the polymer-modified mortars are almost the same. Drying in a drying oven for the polymer-modified mortars before the fire tests brings about the appropriate evaluation of their fire-protecting performance, and the noncombustibility depends largely in the polymer type and the polymer-cement ratio. From the test results, the authors propose the fire-protecting performance test methods for polymer-modified mortars for buildings.

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This paper describes a study on the long-term strength development and carbonation of high-strength concrete in full-scale models. Four types of full-scale columns were made of two high-strength concretes, which design strength were 60 and 100 N/mm² (Fc60 and Fc100), respectively. Core specimens were drilled out of the columns at the age of 15 years. The compressive strength and carbonation depth of the core specimens were tested. As a result, the increase of strength from 91 days to 15 years was clearly recognized in both Fc60 and Fc100 concretes. The strength of core specimens taken from the center of the column was higher than that of core specimens taken from the corner of the column. The carbonation depth at 15 years is 0 mm, in both Fc60 and Fc100 concretes. However, the consumption of Ca(OH)₂ and production of CaCO₃ were revealed by XRD analysis. C₃S and C₂S still remained in both Fc60 and Fc100 concretes at 15 years.

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The final objective of this study is to enhance the performance of clay wall on bamboo lathing and to improve its productivity in order to utilize this wall construction system widely for wooden detached houses. In this paper, various tests and analyses were carried out to investigate the properties and mix proportion of wall clays which had been used normally in some main districts. Test samples were prepared by well-skilled plasterers. The followings are concluded from the test results. Some of the soil tests and analyses are adaptable as the quality tests of wall clay. The grain size distribution is one of the most important characteristic having correlation with the consistency, drying shrinkage and compressive strength. The theory of laying undercoat with intermediate coat are different depending on the districts.

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The effect of green roofs to delay rainwater drainage timing, which is expected to prevent the serious flood disaster in big cities at heavy rains, is studied. Delay times and quantities of drainage water were measured for various kinds and thickness of soil layers and various conditions of lawn grass at heavy rains. It was made clear that the relation between the drainage delay effect and the composition of the soil layer, and the effect of treatment of the lawn grass. The simulation program was furthermore developed on the basis of the measured results, and the method for estimating quantitatively the drainage delay effect of green roofs was proposed.

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The phenomenon rubbed by the heel at the time of walk has effect on change of slip resistance of a floor.
The actual abrasion experiment rubbed by the heel was conducted. As a result, the abrasion sample was able to be obtained and change of slip resistance has been grasped.
The accelerating abrasion machine of the floor which gives the abrasion load by the phenomenon to rub was developed.
With the developed accelerating abrasion machine, change of the slip resistance obtained in the actual abrasion experiment is reproducible.

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The purpose of this study is to present the evaluation method of contact resistance between hands and building elements from the view point of safety. In this repot, we firstly carried out sensory test, to make the evaluation scales of posture keeping in slipperiness with hands. Next, we developed the slip meter that could measure the slip resistance of plane samples. Then, coefficients of slip resistance of the plane samples by various slider materials, shapes, vertical loads and pull speeds are searched with the slip meter. Also, the relations are investigated between slip resistance and evaluation scales of posture keeping in slipperiness. As a result, we presented main points of measurement method of slip resistance of building elements and members with hands.

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The stochastic method is widely used to simulate high-frequency earthquake motions. However, it still has a crucial defect that simulated high-frequency motions are underestimated in amplitude and duration. This is mainly caused by neglecting the effects of multiply reflected and transmitted waves and scattered waves. We remove this defect from the method in a simple practical way. We firstly introduce into the method the hypocentral-distance dependent shaping window which is inferred from borehole data provided by KiK-net network. We secondly introduce the radiation coefficients transiting along with propagation from the theoretical respective value for SH and SV waves to the isotropic value common to the two wave types. The usefulness of the improved method is demonstrated by reproducing three-component acceleration time histories of the 1995 Hyogo-ken Nanbu earthquake in amplitude and duration as well as spectra at all the sites in the Osaka Basin

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This study performed a damage survey and seismic performance evaluation in the Kuroshima district, which was subjected to strong shaking during the 2007 Noto Hanto earthquake. From the results, the base shear coefficient for wooden structures is relatively high; 0.51 for wooden houses and 0.78 for mud-walled storehouses. The mud plaster wall, hanging walls, and spandrel walls are also an important seismic resistant element. Structural regionality of the wooden house is found in equivalent height, peculiar mode, and base share coefficient. As a conclusion, high strength of wooden structures cannot always reduce the maximum response deformation angle.

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We present a vertical seismic isolation device for limiting the response acceleration less than a specified value. In Japan, strong near-fault earthquakes have been recorded frequently in recent years. And the demand is increasing for developing vertical seismic isolation devices to protect important objects. In vertical seismic isolation, large deformation due to gravity takes place if the seiffness is simply reduced. To overcome this difficulty, we use constant-load springs, which sustain constant load regardless of displacement. Since the object placed on the device is supported only by constant-load springs, transmission of the reaction force can be limited within a specified value. This way, the peak response acceleration of the object can be controlled regardless of the kinds and magnitudes of earthquake ground motions. This paper demonstrates the effectiveness of the present vertical seismic isolation device thorough experiments and simulations.

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The goal of this study is to clarify dynamic responses of the Ojiya west high school that is near an observation site where severe ground motions were obtained during the 2004 Niigata-Chuetsu Earthquake. Firstly, field surveys of the superstructure and geological surveys were conducted. Next, simulation analyses were performed using the strong motions and the suppressible factors of structure damage were verified on the basis of the analyses results. Structural surveys clarified that both the superstructure and pile foundations of the school building had almost no damage by the earthquake. Geological surveys and site response analyses clarified that the surface clay layer strongly softened during the earthquake. Finally, simulation analyses by the 3-D superstructure-pile foundation model clarified that nonlinear soil-structure interaction greatly affected the structure response and suppressed the damage of superstructure and pile foundation.

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Connecting an adjacent new building with passive energy dissipation devices is one of the feasible ways to reduce response of existing buildings. In this paper, two single-degree-of-freedom systems (one is nonlinear and another is linear) connect each other with the connecting spring and damper to improve earthquake protection of old nonlinear buildings. This paper shows an optimum connection property which minimizes plastic strain energy contributing directly to damage of the buildings under white noise and mass ratio and frequency ratio which bring out better coupling effects. It is also reported that the response of the model is measured under several earthquake ground motions. The result can show efficiency of the proposed method.

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The beam element for three-dimensional pure steel frames proposed by the first author is extended for steel-concrete composite members. The authors call this approach the ” fibered plastic hinge method”. The stress-strain relation of a concrete fiber is modeled as an elastic-perfectly plastic type in this study. Comparisons with the authors' experimental results on RC beams strengthened by carbon fiber sheet and available test results on steel-concrete composite columns and frames show that the developed beam element has a sufficient accuracy for bending problem although there are some limitations. The element may be used to examine a performance of moment-resistant steel-concrete composite frames.

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It is very important to construct analytical models that can express the actual seismic strength of buildings in order to estimate the damage of building against the future earthquakes. Nagato and Kawase (2001) create such models by comparing the building damage ratios based on the damage statistics of RC (reinforced concrete) buildings during the Hyogo-ken Nanbu earthquake and those of the nonlinear response analyses of buildings models assumed from the current building code using simulated strong motions. In this paper, Nagato's models are improved by considering both the effect of amplification of the earthquake motion in the surface sediments and the effect of the soil-structure interaction. As the results, more appropriate models are proposed, especially for 9- and 12-storied RC buildings.

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The main objective of this research is to develop the vibration control procedure of several modes for large span structures using spatially distributed MTMDs (multiple tuned mass dampers). We have already proposed the set-up procedure for design parameters and the spatial arrangement of MTMDs to control various vibration modes effectively. In this paper, we studied analytically the influence of division number of MTMDs on the vibration control performance using a spherical shaped spatial structure. As a consequence, we could recognize that increase of division number tends to improve the control performance of the over all structure. And we considered the reason from the point of variation of equivalent mass that is an important parameter to design the multi-degree-of freedom system.

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Many of tensegrity frames have infinitesimal mechanisms that are usually stabilized by the prestress. However there are some special tensegrity frames having mechanisms that can not be stabilized by the prestress. They exhibit large displacements, without affecting the initial prestress states, associated with finite mechanisms. In the paper three classes of the tensegrity prisms, diamond-type, star-type and complex-type, are investigated by using group representation theory. It is then shown that only complex-type tensegrities have finite mechanisms. Infinitesimal mechanisms of three types of tensegrities are classified and finite mechanisms of complex-type tensegrities are listed by using group representation theory. Relationships to the force density method are also discussed.

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A method to construct nonlinear characteristics of woodframe houses on basis of hysteretic characteristics of beam-column and braces, which are extracted individually from pseudo dynamic tests is proposed in this paper. A proposed hysteresis model is expressed by combining two types of Bouc-Wen model; one is of spindle-shaped and the other is of strong slip behavior. The applicability of the proposed model is confirmed by a simulation analysis for the results conducted by shaking-table test. It is shown that the computed results with use of the proposed model agree satisfactorily well to the experimental results.

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We present an approach for estimating the semi-rigid characteristics of a column-nuki (a horizontal member going through a column) connection, which play a crucial role in earthquake resistance of Japanese traditional timber buildings. With the proposed approach, we attempt to provide simple numerical models for column-nuki connections at the stress resultant level from local compression tests of wood elements taking joint details into account. In the local compression test, a rotated steel plate is pressed into wood elements keeping its rotation angle constant. Based on the results of a set of the local compression tests, wherein the rotation angle is changed parametrically, we propose a formulation to estimate the skeleton curve of the moment-rotation angle relationship for a column-nuki connection. The formulation was verified by comparing the estimation with the results obtained from a cyclic loading experiment of a column-nuki assembly.

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The objective of this study is to investigate the effect of the moisture content of lumber at the fabrication on the racking resistance of shear walls and the change of the resistance due to the time lapse with the drying of lumber. A summary of the results of the racking tests is as follows: The stiffness and the ultimate strength of plywood sheathed walls just after the fabrication increase as the moisture content of lumber used decreases. The stiffness decreases with the time lapse regardless of the moisture content of the lumber used, while the ultimate strength of the wall used green lumber increases due to the time lapse with the drying of the lumber.

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Splitting of wood loaded perpendicular to the grain is a critical issu in timber engineering, and the splitting and failure of wood at its connection are studied in some articles. But to research the characterization and to evaluate that fracture is very difficult. Now we have no standard method to determine the fracture toughness of wood for timber engineering. So we need some simple or useful methods.
Thus we conducted CT test with some woods for structural glulam. Durning the tests, we checked behaviour of crack on the surfaces. We understood that fracture of wood starts at maximum load or after that, but the propagation is unconstant. Then we caluculated J_IC, and comparised with some past results. Additonally we studied the relationship between the work-energy and crack length.As a result, we proposed that crack initiation point is almost at maximum load in CT tests. And we understood followings,
1)Crack length (a₀/W=0.5-0.6) is useful to calculate lower limit of J_IC in CT test.
2)To calculate J-integral, we need FEM-analysis with in-depth element properties

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The objective of this study is proposing a design method to estimate the load-slip characteristics of the bolted joints with steel side plates. It is well known that maximum load of the joints greatly exceeds the allowable load.In the current design spceification, the ultimate load can be determined by the use of the increment factor however, the load-slip behavior cannot be predicted without using the numerical analysis.The method presented here is applying a bi-linear model to the load-slip relationship until the ultimate state where the axtial force in the bolt must be taken into account. Characteristic values conducted here generally showed good agreement with the verification experimental results.

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In order to reduce seismic response and damage of wooden houses effectively, a series of so-called shear-link-type passive control systems, which include both velocity- and deformation-dependent dampers were proposed. In this study, a number of shaking table tests of the full-scale two-story wooden frame specimens were carried out. The specimens are composed of conventional post-and-beam with structural plywood, or K-brace and damper for structural element. Performance of specimens is discussed by referring to story drifts, base shear forces, damper deformations and forces, and ratio of story's stiffness. Dynamic properties of the structures such as equivalent periods and damping ratios are also discussed. Test results are compared with the prediction made by calculation of response and limit strength.

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The seismic retrofit concept of using aramid fiber belt with initial lateral prestressing for RC columns was proposed by one of the authors. An important point of this technique is that the lateral prestressing can be initially introduced into column through aramid fiber belts using couplers and thus the benefits of active confinement as well as passive confinement can be captured. To analyze the nonlinear behavior of RC columns retrofitted by the proposed technique, the appropriate constitutive law of confined concrete is essential. Therefore, to establish the constitutive law of confined concrete, axial compression tests of RC columns externally confined by aramid fiber belt prestressing were conducted. The stress- strain relationships of concrete and aramid fiber belts are obtained through the experimental investigation. Finally, an appropriate constitutive law of confined concrete for the mensioned retrofit technique is proposed.

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In Architectural Institute of Japan (AIJ) standard for structural calculation of reinforced concrete structures and General Building Research Corporation (GBRC) design guideline for mechanical anchorage in reinforced concrete joints, development length of R/C sub-beam reinforcement into main-beam is specified as the value speculated by the required development length of main-beam reinforcement into beam-column joint. However, this adequacy is not verified by the experiments in the past. In this study, a number of experiments are carried out to identify the anchorage strength and required development length of R/C sub-beam reinforcement using mechanical and bent anchorages. Main parameters of experiments are type of anchorages, development length, concrete strength, and detailing of reinforcement. Consequently, design equations on required development length and the allowable stress of R/C sub-beam reinforcement are proposed and design examples are demonstrated.

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In this study, bending and shear tests were conducted to understand the seismic performance of reinforced concrete beams formed by joining together two precast beam-end elements at the midspan using cast-in-place concrete with splice-bar joints of main bars. A total of 11 specimens were used, and the parameters were the strength of main bars and cast-in-place concrete, transverse reinforcement spacing and the amount of U-shaped reinforcement in the lap splices region. As a result of the test, a design method for splice-bar joints necessary for flexural yielding of beam ends was developed. Also, a bond splitting strength evaluation method taking into account the effect of U-shaped bars and the influence of the stress gradient, developed by modifying evaluation formulas currently in use, was proposed.

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This paper proposes a series of simple mathematical expressions which govern the ultimate behavior of two-dimensional reinforced concrete beam-column joints based on an observation of a failure crack pattern, and its compatible kinematic field, overlooked by the past researchers. The kinematic model is named nine DOF model in this report and combined with non-linear biaxial constitutive relation of concrete and steel to bear simple algebraic expressions for the ultimate moment capacity and moment at balanced failure, applicable to symmetric interior beam-column joints subjected four symmetric moments transmitted among the four ajacent members. The ultimate moment capacity is defined at which tensile yielding of longitudinal bars passing through the joint in the joint causes the expansion of diagonal cracks in the joint as well as local rotation of concrete panel and local crushing of concrete. The balanced failure of beam-column joint is defined at which tensile yielding of longitudinal bars passing through the joint and crushing of concrete start simultaneously. Simple equations for the upper bound value for the amount of reinforcement precluding the joint failure before yielding of longitudinal reinforcement are also brought.

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In the beam-to-column connections, there is a possibility that the plastic deformation capacity decreases by brittle fracture. Full scale test on beam-to-column connections with ordinary type weld access holes was carried out. Major test parameter was temperature. The plastic deformation capacity and the load-carrying in the transition area were evaluated from the test result, and were compared with previous experimental results. Deformation capacity is largely influenced by the mechanical property of the material. The material used in the test was special one and had unique properties. Then, the material properties were replaced and corrected by the ordinary one in analyzing the deformation capacity.

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The behavior of centrically loaded box-section steel columns until they have reached a stage of complete collapse was studied by carrying out a series of experiments and analyses. The results obtained from this study can be summarized as follows: (1) The behavior after the yield of the steel columns can be divided into two types; the flexural buckling type in which the progress of lateral deflection results in collapse and the local buckling type in which the local buckling occurring successively along member-length results in collapse. A conditional expression of members for the discrimination of these two types of behavior was derived. (2) A method for analyzing the behavior of flexural buckling type members was developed and the validity of this analysis method was confirmed in comparison with the experiment results. (3) A model to estimate the load-deflection relationship of local buckling type members was derived.

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One of authors proposed a sheme for Internet-based structural analysis in which many reserchers worldwide can collaborate and unify their different programs and structural models.
This paper first introduces the structural loading system of an exposed column-base.This loading system enables us to simulate the variation of fotational stiffness and bending moment carrying capacity under varying axial force.Hence,the technique of Internet-based structural analysis is used to perform the collaborated pseudo dynamic test on a building frame with a non-slip-type exposed columncase subjected to vertical and horizontal forces.The results show the simplicity of the collaboration procedures,the stable transfer of information between programs and loading system,and the overall complicated resisting behavior of a building with column-bases.

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The hybrid structural beam which consists of reinforced concrete in the beam ends and H-shaped steel in the middle of the span has been proposed. However, it is essential to design a building using this structural system that performance evaluation of the hybrid structural beam is made clear. This paper presents both an evaluation method of the deformation capacity and a shear resistant mechanism of the reinforced concrete section based on the mechanisms of stress transfer between steeel and concrete for the hybrid structural beam. It was demonstrated that the proposed evaluation method was suitable by the result of both our structural tests and the existing tests.

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In this study, the contact detonation tests were conducted on six kinds of fiber-reinforced concrete slabs, and then spall damages created in them were compared with those in S-PEFRC (fiber-reinforced concrete with polyethylene fiber of strand type) slabs. The main results obtained are as follows: 1) all of fiber-reinforced concretes investigated in this study were effective in reducing spall damage as compared with normal concrete; 2) total damage depths in various fiber-reinforced concrete slabs could be generally estimated by formula for estimating that in the S-PEFRC slab; and 3) in case the modified-scaled concrete thickness was small, the S-PEFRC had somewhat better blast resistance than other fiber-reinforced concretes of which flexural toughness was equal to that of the S-PEFRC.

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