Control of air content and resistance to frost damage are essential for fly ash concrete. This paper demonstrates a possibility of controlling the air content of fly ash concrete by the basic properties of fly ash. It also elucidates the tendencies of the effects of the presence of fly ash, mixing conditions, and type of air-entraining admixture on the air content, air void system, and air loss by agitation. The frost resistance test results of fly ash concrete slightly lower than normal concrete are found attributable to the fact that its air-void spacing factor is larger than normal concrete and that the initial curing time of 2 weeks specified for freezing and thawing testing is insufficient for fly ash concrete.

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The strength and hardness of concrete slab surface is considered significantly affected by bleeding of concrete. It has been reported that dewatering by vacuum processing is quite effective to obtain high density of concrete. The method, however, has not been successfully used for the concrete work in the field of building construction, compared with that of civil engineering works in Japan. In the present study, firstly the state of the art concerning vacuum processing method is reviewed and the newly proposed vacuum processing method is introduced. Then the effect of the proposed method on concrete properties of slab is examined by a series of experiment in order to find more reasonable and effective way in the application of the proposed method.

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This paper deals with the time-dependence of fluidity and thixotropy of high fluidity concrete mixed by adding polycarboxylate-based superplasticizer. With taking both the hydration and the physical flocculation of cement particles into consideration, the increase of apparent viscosity and Bingham's constants with the elasped time of standstill, and the time-dependence of apparent viscosity in agitated state were investigated theoretically. It was concluded that whether the increase of apparent viscosity or Bingham's constants in stationary state or the time-dependent behavior of apparent viscosity in agitated state, are dependent on the hydration rate of cement and are also affected by the dosage of superplasticizer, temperature, the reference time of investigation and the dispersion degree of cement particles at the reference time. Moreover, the influences of the magnitudes of applied stresses and their lasting times on the shape of hysteresis loop of shear strain rate-shear stress relationship and its surrounding area were inquired quantitatively.

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This paper shows the effects of size, shape and volume fraction of fine aggregate on cohesion, angle of internal friction and change of cohesion with time as parameters related to the yield value of fresh mortar. The main conclusions are as follows : 1. The dispersing distance of particles - particle diameter ratio (DDDR) can be applied as a parameter for expressing the effects of size, shape and volume fraction of fine aggregate, and the relationship between DDDR and logarithm of each parameter is linear. 2. The parameters used in the model are affected by not only DDDR but also the slip between fine aggregates and cement paste.

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The effect of the fatigue resistance of sealing joint at crossing area by rocking motion of curtain wall panels was studied experimentally and analytically. The rocking fatigue apparatus for the cross type specimen was developed and the number of cycle when crack was detected to movement was measured. Then, stresses and their distributions were studied using the FEM method considering nonlinear behavior of a sheet. As a result, we successfully obtained the data of fatigue resistance of sealing bead using new apparatus and the fatigue resistance of the cross part area of sealing joint should be lower performance than at the ordinary area of sealing joint because the stress level was higher at the area.

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The degradation state of the concrete used for the foundation of houses was investigated. The purpose is obtaining the data for prolonging the life of a single-family house. Consequently, there were much foundation with intense degradation (strength fell and carbonation advanced). In order to grasp the actual condition, it is required to investigate the foundation of existing houses more. And if required, it is necessary to work on a measure.

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The contact thermal sensation variously changes material type and material temperature. This paper examined the method of evaluating the contact thermal sensation of material by a physical property. Materials used for the experiment were 6 types of which the thermal property differed, and the surface temperature of these materials was changed to 0℃〜50℃. The following were measured contact thermal sensation in touching with material by a hand and temperature change of contacting part of the palm. As a results, contact thermal sensation and possible contacting time could be evaluated by the contact temperature change. It is possible to touch for 600 seconds within contact temperature change -6.5℃〜+6.5℃. It feels cold in contact temperature change -6.0℃. It feels warm in +4.8℃. The possible contacting time was also able to be evaluated by contact temperature change.

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The objective of this study is to establish an indication method for the degree of the recognition of change of floor system in walking space, focussing on the effect of hardness and walking sound. First, using twenty-five sets of two sample floors, the psychological scale to measure the degree of the recognition is constructed by the sensory test. Second, hardness and walking sound of sample floors are measured by using two apparatuses. Finally, on the basis of the difference of hardness and walking sound, the psychological scale is represented, and the index of the degree of the recognition is proposed.

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In the earthquake resistance design of frame structures, it is a general requirement to give a suitable target value of the column over-design factor (COF) for which the occurrence probability of unpreferable failure modes can be limited to within a specific tolerance. In the present paper, the likely failure modes of weak-beam-strong-column designed structures under uncertain loads and with uncertain member strengths are investigated and the target value of COF is discussed in probabilistic terms under three failure levels, i.e., Level 1 -- strictly beam-hinging pattern, Level 2 -- beam-hinging pattern and Level 3 -- total collapse pattern. It was found that : (1) For levels 1 and 2,the larger the number of bays and stories, the larger the target value of the COF. For level 3,the target value of the COF is independent of the number of bays. (2) The higher the reliability level is set when the structure is designed, the smaller the target value of the COF is required to limit the probability ratio to within a given tolerance level.

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With an aim to predict on the aerodynamic characteristics and the unsteady behavior of separated flows around the rectangular cylinders with small side ratio at Re≒order of 1,000,the experiments in wind tunnel and Large Eddy Simulation(LES) are conducted. We try to establish the complementary technique between numerical simulation and wind tunnel test. Firstly, it is shown that the present experiments in wind tunnel at 3,000<Re<10,000 are valid about the aerodynamic characteristics, compared with the past experiments. Also, the characteristics of flow patterns are investigated with the use of the frequency distributions, which is calculated from the time history of the drag coefficient. Secondly, we discuss on the associations of aerodynamic characteristics between the computations and the experiments, and clarify the problems with our computations on the flows with irregularity and unsteadiness. Also, the characteristics of flow patterns are comprehended on the basis of the frequency distributions of the computations and the experiments. Further, we reproduce two flow patterns of the low and high pressure mode and perform a detailed investigation of the relation between the separated shear layer and Karman vortices.

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In completing into seismic design for high-rise buildings constructed on soft soil layer, it is necessary to consider soil non-linearity. It must be discussed how to predict bedrock motions based on surface motions and whether surface motions can reappear by nonlinear response analyses subjected to predicted bedrock motions. This study investigates applicability of characteristic method to base motion analyses and direct integration method to nonlinear response analyses. The simulation analyses are carried out using the strong ground motions recorded at the KiK-net stations near the seismic fault of the 2000 Tottori-ken Seibu earthquake (M_J7.3). Observed motions reveals that the soil non-linearity plays an important role in site amplification between the two vertical array points during the main shock. The base motions and surface motions calculated by proposed methods show good correlation to observed ground motions.

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This paper proposes a control algorithm for hysteresis dampers with semiactively-controlled slip-force levels. In these dampers, the magnitudes of the slip-force levels are controlled utilizing absolute acceleration information. In such dampers, the hysteresis is significantly influential on the control effects and greatly depends on how to set the slip-force level. The relationship between the slip-force level and control effect is discussed for the purpose of establishing effective control scheme for multi-story buildings by conducting computer simulations and scale-model experiments.

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This paper proposes a semiactive control strategy utilizing variable slip-force level dampers. Integrating a simple but effective control algorithm, the proposed scheme controls the damper slip-force level so as to exhibit hysteresis regardless of the response. The employed algorithm does not set the magnitude of slip-force level but determines the time at which the damper should start to slip. This scheme provides high-rise buildings with an autonomous-decentralized system. After presenting the control effect through the theoretical analyses, the feasibility of utilizing oil hydraulic dampers for this scheme is demonstrated.

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Predicting building damages caused by a destructive earthquake requires both earthquake ground motions evaluated for a prescribed scenario and vulnerability functions established by actual building damages. It is not easy to obtain accurate vulnerability functions because of insufficient number of observed data and spatial variability of strong motions. The purpose of this study is first to understand a relationship between the strength indices and then to establish vulnerability functions by using building models constructed by Nagato and Kawase (2001) with observed ground motions as input waves. Finally we verify these functions by comparing them with the observed damage during the 1995 Hyogo-ken Nanbu earthquake. We found that it would be better to use PGA^*PGV or JMA seismic intensity to construct vulnerability functions.

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This study is to synthesize knowledges about the vibratory characteristics and the earthquake response of a mid-story isolated system. First it is shown that an equivalent two mass system is useful enough for estimating the vibratory characteristics of the mid-story isolated system from the results of eigenvalue analysis. Then a response analysis based on energy balance applies to the equivalent two mass system, and the seismic prediction method which summarized the foregone knowledges is proposed. Futhermore, it is clarified that the mid-story isolated system holds promise of adecuate aseismic performance by using the seismic prediction method proposed.

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In this paper, the procedure of system identification by prediction error method, using nonlinear restoring force model, is presented, and several system identifications of two base-isolated structures using two-directional recorded seismic response are carried out. In the system identifications, the restoring force of the base isolation system is assumed to consist of several piecewise restoring force models, including multiple shear spring model. As results of using trilinear multiple shear spring models, both the estimated hysteresis shapes and the time histories show good agreement with those obtained directly from the observed data.

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A passive control system with a stud-type viscoelastic damper has attracted a strong interest due to its advantage of preserving great freedom in architectural planning. Dynamic characteristics and time-history responses are discussed both experimentally and analytically for four different stud-type systems. Simplified static methods to estimate stiffness and damping as well as member forces of the systems are proposed. The static methods derive exact solutions, and agree well with the dynamic experiments. The methods are also found applicable to a variety of other different systems having dampers of linear viscosity.

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Investigation on circular hole Void slab is executed to reduce the slab weight, in which cylindrical steel pipes or other materials are embedded in the center part of cross section in one direction. In this paper, the characteristics of the bending rigidity of the void slab and stress concentrations are confirmed and clarified by direct numerical method. The coefficients of bending rigidity in both directions and of stress concentrations are obtained in accordance with void diameter-thickness ratio. The purpose of this paper is in obtaining the basic design data. This numerical analysis is within the linear theory, and the yield or the limit strength and the final deformation states not evaluated.

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The 1994 Northridge and the 1995 Kobe earthquakes realized us the importance of grasping damage information on built-up areas in the early stage for recovery activities and restoration planning. One of the remarkable characteristics of synthetic aperture radar (SAR) is its capability of recording the physical value, called the backscattering coefficient, of the earth's surface under independence of weather condition and sun illumination. Therefore SAR could be a powerful tool and possibly be used to develop a universal method for grasping damaged areas during disasters such as earthquakes, forest fires and floods. Detailed ground truth data with building damage due to the 1995 Kobe earthquake provided us the opportunity to examine the relationship between the backscattering property and degree of damage. From the above analysis we have already developed a method to detect areas of building damage. In this paper, we introduced the automated detection method using the average difference in the backscattering coefficient and the spatial correlation derived from the pre- and post-event speckle-reduction-filtered images. Then we applied this method to the images taken over the area hit by the 1993 Hokkaido Nansei-Oki, Japan, the 1999 Kocaeli, Turkey, and the 2000 Gujarat, India earthquakes, and then the accuracy of the proposed method was examined by comparing the results of the analyses with those from the damage surveys.

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Discussed in this paper is the bending moment supporting mechanism of laminated rubber bearings with a hollow circular section. The flexure stiffness of the hollow circular rubber bearing is analytically studied. The followings are the key issues discussed in this paper. (1) Derivation of the general governing equation that determines the distribution of pressure inside of the laminated rubber material. (2) Evaluation of the effect of bulk modulus on the bending stiffness. (3) Proposition of a simple formula that is close to the rigorous solution. (4) Discussion of the performance of hollow circular sections based on the analytical solutions.

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This experimental study aims to investigate the dynamic properties of the timber shear wall structures with eccentricity. All the specimens were one-story system, having the wall layout arrangements so that the eccentricity ratio, Re may become 0 to 0.599. In addition, the horizontal diaphragms had two specifications with high and low shear stiffness. These dynamic properties were examined by shaking table tests. Through these experiments, the following result were obtained. 1) The first natural frequencies of the each specimens were so decreased as to increase Re. 2) Distributions of seismic lateral force became trapezoidal or triangular, which were different one in static state (considered as rectangular distribution). 3) In serviceability state, shear stress concentration ratio in dynamic state were 14〜78% larger than static theoretical value. 4) In ultimate limit state, shear stress concentration ratio in dynamic state were smaller than one in serviceability state.

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Static loading tests of wooden shear wall structure with eccentricity were carried out. The tested models were 3.64m in X-direction, 4.55m in Y-direction and one story in height. By arranging the 6 wall units of different type, the 7 models with different eccentricity were tested. The models were loaded in X-direction to give uniformly distributed load and without confining the deformation of the floor. Through these experiments, it was made clear that if the walls in X-direction yield and the walls in Y-direction do not yield, the shear force concentration ratio (the ratio of the bearing shear force to the shear force in proportion to its stiffness) of the weaker side becomes smaller. However, after the walls in Y-direction yield, it becomes larger to shear force concentration ratio when all walls don't yield.

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The anchorage capacity of the cone shaped splitting failure is focused in this paper. The cone shaped splitting capacity is examined by the pull-out testing with the series of twenty-nine specimens. Transference of stress from the anchored beam rebars to the concrete at the potion that is simulating the beam-column joint is observed. The results of the tests suggest the followings : l) The cone shaped splitting capacity is corresponding to the lateral tensile capacity of concrete and hoop reinforcements in the beam-column joint. 2) Anchorage strength in case of the side burst failure is estimable as safe with the existing empirical formula. 3) The maximum bearing stress at the anchor-heads is three times as large as the compressive strength of concrete. This paper also proposes a simple model to estimate the bond stress of the anchored reinforcements in the member with flexural stress

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Dynamic loading tests of reinforced concrete columns (RC columns) under the varying axial load were carried out and the complicated restoring force characteristics including the effects of varying axial load and loading rate have been obtained. On the basis of the test results the dynamic restoring force model of RC column under seismic load is derived. The model expresses the effects of varying axial load and loading rate and can be applied easily to seismic response analysis. It is also ascertained that the presented model is useful by comparing it quantitatively with the dynamic loading test results.

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In this paper, a test procedure and test results of shaking table tests that specimens are partial frame model of damage tolerant structure with buckling resistant brace are shown. Four kinds of buckling resistant braces, which performs different characteristic, are set in the steel frame. Two different type waves (Kobe and Hachinohe) are inputted in the shaking table with four input levels (level1,2,3,4). In this study, Level 3 and 4 are configured as very severe earthquake. As a result, it was confirmed that buckling resistant brace can behave effectively in each input levels under the condition sat within the frame. The damper can reduce total damages at beam-to-column connection of the frame, unless the damper reaches a fracture.

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This paper presents a seismic design procedure to estimate the ductility demanded of hysteretic dampers in steel frames. Critical parameters that control the earthquake response of steel frames with hysteretic dampers are characterized and incorporated into the equivalent SDOF representation. Maximum and cumulative plastic deformations induced in hysteretic dampers are derived in explicit forms as functions of these parameters, and the accuracy of the estimations of plastic deformations is demonstrated through a comparison with numerical results.

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This paper presents a study of seismic damage in low or middle rise steel structures. In order to evaluate the damages of stories and structural members, seismic response analyses about 64 existing steel structures were carried out using 4 seismic waves. From the results of analyses, following conclusions were obtained. 1) The seismic response drift angle of each story can be estimated using base shear coefficient and coefficient of shear distribution at each floor. 2) The damage of columns are slight in case the column-to-beam strength ratio are larger than 1.5. The damage of panel zone increased when the column-to-beam strength ratio are smaller than 1.5,because the ratio of the yield strength of panel zone to the plastic bending strength on connected members is related very closely to the column-to-beam strength ratio.

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This paper evaluates strength of H-shaped brace constrained flexural buckling by rectangular hollow section steel. The brace has unconstrained area at both fixed-ends. It is assumed that the brace and the steel tube deform continuously. The formulas of strength evaluation are induced using continuous bar model of non-uniform section. The propriety of strength evaluation methods was verified by structural experiments. As a result, it was shown that the collapse mode changes from the bending yield of constraining member to the yield or the local buckling of the brace caused by axial force and additional bending moment at the unconstrained area.

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In this paper, a simple column-beam joint in steel structures is experimentally studied. The joint is achieved by means of filling steel fiber reinforced cementitious composites at the gap. In the test, simple beam specimens are employed by filling steel fiber reinforced cementitious composites, high strength mortar and concrete at the joint, and cyclic load is applied. The results show that the specimens with steel fiber reinforced cementitious composites give enough stiffness and strength without prominent damage in comparison to the specimens with high strength mortar and concrete. It is concluded that the simple column-beam joint with steel fiber reinforced cementitious composites is applicable.

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The purpose of this study is to show the useful numerical plasticity model about the multi-axial stress-strain relation for various aluminum alloys under cyclic loads. The numerical plasticity model for structural steels which authors have proposed is modified for aluminum alloys. The validity of the model is shown by comparing results of uni-axial cyclic load tests of several aluminum alloys and bending tests of beams with analysis results. And the relation between the material characteristic and the hardening parameters shows that the hardening parameters are approximate only at 0.2% offset proof stress and tensile strength.

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