A computer-based numerical model is presented, in which hydration and micro-structural development in Portland cement-based materials can be simulated. In the proposed model, kinetic of mineral component in cement is determined explicitly, and specific heat of hydration product and unhydrated cement is taken into account to precisely simulate adiabatic temperature rise in concrete. Firstly, the specific heat is measured for unhydrated cement as well as cement paste composed of hydration product. Based on the results of degree of hydration determined by the amount of combined water, the specific heat of hydration product is calculated. Secondly, the Computational Cement Based Material model (CCBM) is improved so that it can take into account the effect of composition of mineral component in cement explicitly. Comparing the simulation results with the experimental results of adiabatic temperature rise, the proposed hydration model shows preferable predictions.

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In this study, the relation between the compressive strength of high strength concrete which mixed two kinds of crashed stones and the blend condition of crashed stones was analyzed. The results indicate that compressive strength of high strength concrete becomes small in proportion to blend ratio of the crashed stone that is not suitable for materials of high strength concrete, and that compressive strength of high strength concrete can be estimated based on average physical properties of stones in coarse aggregate.

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In this paper, the tendency of labor accident affected by hot weather ambience were analyzed and discussed. At first, severity of construction works was evaluated in relative metabolic rate (RMR), and temperature limit of works was shown as some index, such as the wet bulb glove temperature (WBGT). The frequency of heat attack occurrence correlated with the number of the days when the maximum temperature became higher than 30℃. Because many processes were executed over the temperature limit, labor accident tended to occur in hot season, and particularly the fall accident from 10 a.m. to 3 p.m. due to high temperature.

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In this study, in order to improve the detection accuracy of defective parts in the wall by infrared thermography, surface color and dirts on the wall are quantified as the color values and spectral absorption obtained from the digital image. Furthermore, correcting method of the infrared thermography image by the surface color value is investigated. According to the results, the thermal difference of surface of wall by inner deffect is in good correlation with the spectral absorption, and it is clarified that it is possible to correct the infrared thermographic image by the analysis with spectral absorption obtained from the digital image.

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With the aim of developing Cr-bearing rebars having required resistance to deteriorative environments prone to carbonation with or without chloride attack, ten types of steel bars having different Cr contents were embedded in concretes with chloride ion contents of 0, 0.3, 0.6, 1.2, and 2.4kg/m^3 to fabricate specimens assuming such deteriorative environments. After being carbonated to the reinforcement level, these concretes were subjected to corrosion-accelerating cycles of heating/cooling and drying/wetting. The time-related changes in the corrosion area ratio and corrosion loss of the Cr-bearing rebars were then measured to investigate their corrosion resistance. The results revealed that the Cr content required for corrosion resistance in a simple carbonating environment was 5% or more. The corrosion-resisting performance of Cr-bearing reinforcement was particularly noticeable with a Cr content of 7% or more. In a deteriorative environment prone to both carbonation and chloride attack, corrosion resistance was evident with a Cr content of 5% or more and 9% or more in concretes with chloride ion contents of 1.2 and 2.4kg/m^3, respectively.

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For precise prediction of strong ground motions from intra-slab earthquakes, we proposed a procedure for determining the parameters of the characterized fault models based on the asperity model. The major parameters were the entire fault area, the seismic moment, the averaged stress drop, the area of the asperities, the stress drop on the asperities, and the short-period level of the acceleration source spectrum. We assumed the seismic moment, the area of the asperities, and the short-period level from the data of the actual intra-slab earthquakes, and evaluated the other three parameters by the three theoretical relations between the major parameters. Based on this assumption, we generated a characterized fault model for the 2003 Miyagi-Ken Oki, Japan, earthquake (M_J 7.1) to simulate strong ground motions. The resultant motions showed pretty good agreements with the actual records and with the empirical attenuation relation of Si and Midorikawa (1999).

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The peak ground acceleration at K-NET in Ojiya during the Mid Niigata Prefecture Earthquake in 2004 is significantly larger than that at JMA in Ojiya, while the trend reverses in other earthquakes with less intensity. Strain-dependent shear moduli of surface soils at both stations are estimated based on the accelerograms obtained only at the ground surface together with in-situ tests including boring and PS logging. Despite its low shear wave velocity, the near-surface peat at K-NET show weaker nonlinearity than the near-surface silt at JMA, which might have had strong effects on the observed ground motions at the two sites during different earthquakes.

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This paper proposes an active seismic response control system by making use of an energy conversion in damping devices. In the paper, we describe configuration of the system when it is applied to building structure and show how to classify them. We also show the analytical results on energy characteristics and effectiveness of active seismic response control. The analysis on the energy spectra of the seismic control devices, based on the seismic response, clarify the characteristics of the energy conversion and reuse devices. The feasibility of the proposed system to real buildings is discussed considering the energy balance of the system.

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Following the 2001 Geiyo earthquake, which measured 6.7 on the Richter Scale, a lot of damage to the roof-tiles of wooden houses occurred. This damage was more prevalent among houses in the fill part of the hillside, rather than the cut part. The developed area is classified as either a fill part, or cut part, based on GIS (Geographic information systems). The ratio of the horizontal spectrum to the vertical spectrum, known as H/V and based on the micro-tremor measurement of the ground, reaches a peak of approximately 2-4Hz in the fill part. However, it has no predominant frequency on the cut part. It is probable that the damage done to houses with tiled roofs following the 2001 Geiyo earthquake is strongly linked to the predominant H/V frequencies found in the housing site.

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A method is presented for identification of local soft ground position based on measurement of the angle between arrival wave and a vibration source. Vertical ground motion is measured using a circular array of six sensors. The angle between the arrival wave and the source can be determined, based on F-k spectrum analysis of the data. To examine the validity of the proposed method, field investigations were performed. It is shown that (1) The arrival wave angles tend to fluctuate wildly in case that local soft ground locates between the sensor array and the source and the wavelength is about 1.5 times the soft ground depth; (2) The arrival wave angles tend to point in the direction of the source in case that ground between the sensor array and the source is uniform.

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A theoretical approach of elasto-plastic response with constant damping factor is proposed to evaluate transition of natural periods of buildings. The spectrum of the elasto-plastic response is equivalent to that of visco-elastic response in following respects: both values of dissipative energy during one cycle are exactly same, shapes and amplitudes of both spectra are approximately same, the spectrum of elasto-plastic system shows linear response with fluctuations in amplitudes of input motions. The equivalent period of elasto-plastic system indicates significant relation between response amplitude of the system. This mechanism gives appropriate interpretation on the observed transition of natural periods of buildings.

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In this paper, the previously developed AST-Gauss technique is applied to an aircraft impact analysis of New York World Trade Center Tower 2 (WTC2), to evaluate the structural vulnerability and behavior of the aircraft, at the horrifying scene that occurred in 2001. The ASI-Gauss technique is a modified version of the formerly developed Adaptively Shifted Integration (ASI) technique for the linear Timoshenko beam element, which computes highly accurate elasto-plastic solutions even with the minimum number of elements per member. The ASI-Gauss technique gains still higher accuracy especially in elastic range, by placing the numerical integration points of the two consecutive elements forming an elastically deformed member in such a way that stresses and strains are evaluated at the Gaussian integration points of the two-element member. From the numerical results, propagation of the shock waves resulted from the impact and high-level stresses in the structural members were observed. We could also see how the main wings of the aircraft cut through the perimeter columns and spandrels, how the debris moved through the building and to where it caused damage. Moreover, the velocity reduction of the right engine and the location from where it moved out of the building were in good agreement with the observed data.

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This paper presents a revised genetic algorithm for building structural optimization. The presented algorithm can generate the individuals whose structural weights are close to that of the best individual in the previous generation by using the especial crossover technique based on structural weight limit. The presented algorithm is applied to the minimum weight elastic and plastic design problems of 5-story and 8-story plane frames and minimum weight elastic design problems of 15-story and 18-story frames. The numerical results obtained by the presented algorithm are compared with those obtained by the simple genetic algorithm to check the effectiveness.

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In this paper, the effects of adjacent building on soil-structure interaction of spread foundation are studied by the thin layered element method combined with flexible volume substructure method. The effects of the adjacent building on the impedances and foundation input motions are examined. The inertia effect of adjacent building prominently appears on horizontal impedance and rotational foundation input motion. The effects of the factors such as the distance between the foundations, the size and height of the adjacent building, the embedment depth, the stiffness of the backfill soil and three buildings interaction are also analyzed in this paper.

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This study is related to the modeling of the nonlinear stress-strain behavior of frictional materials for wide range of strain. To describe both strain-hardening and also strain-softening behavior, a constitutive equation including a power term is proposed in the following. This equation is shown to offer more versatility for modeling stress-strain behavior in monotonic loading conditions, at from low- to high-strain levels. The proposed equation is relatively verified by experimental data of hollow cylindrical torsional shear tests on both sands as frictional materials, and cement-treated sands as frictional and cohesive materials. In addition, a exponential function is adopted to express the stress-dilatancy relations of cement-treated sands. A dilatancy characteristics of sands and cement-treated sands is expressed by using both functions together.

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The authors have proposed new concept of split-tee connections at bottom flanges of beam ends, which work as beam-end elasto-plastic dampers. They are composed of small buckling-restrained axial members, and their cumulative deformation capacities or energy dissipating capacities are one of the most important indexes for such members' performance, because they are used under very high strained cyclic loadings. In this paper, cyclic loading tests are carried out for beam-end dampers, and their performances against low-cycle fatigue are examined. Their cumulative deformation capacity under random inputs are also evaluated with the proposed method and compared with those of buckling restrained braces.

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This study is to obtain basic knowledge about application of the damper to timber structure with eccentricity. First the mechanical characteristic and analysis model of the damper are re-evaluated by the shaking table test and comparing previous research. Then seismic response characteristics of timber structure with eccentricity installed Viscoelastic damper in, especially the effect of eccentricity ratio and quantity of the damper on maximum response, are comprehended by the shaking table test with Three-Dimensional model. Based on these experimental studies, it is clarified that the viscoelastic damper works on control of torsional vibration effectively by computer analyzing of seismic response mechanism of Three-Dimensional shear deformation model.

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This report describes about full-scale vibration test of housing based on wooden panels construction. The full-scale vibration test on the three-storey housing were carried out. Size of test model is 7,280mm by 7,280mm by 9,824mm. Test model was changed four times by decreasing wall volumes. Each test was called as Phase 1,2,3,4, respectively. The measurement were conducted in the acceleration, relative story displacement, and the pulling out force of base in column, etc. The characteristic of the natural frequency, the acceleration distribution,the load-displacement relation, the deformation behavior and the pulling out force of base in column by the full-scale vibration test were examined by using the result.

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Strength ratio, as defined as shear strength divided by flexural strength, is widely used to assess a failure mode of RC columns. However, several studies have revealed that even columns with the ratio much more than unity occasionally fail in shear during earthquakes, if shear strength is computed based on Truss and Arch Mechanism (TAM). This study is intended to throw light on the above issue. Past tests by the authors show specimens representing old columns with a few amount of hoop tend to fail in shear just when a shear crack occur, or before TAM forms. It is pointed out from discussions on the test results that shear strength should be defined as a value which is larger among the TAM strength and shear crack strength to assess a failure mode of old columns more accurately.

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The seismic retrofit technique of RC column utilizing pre-tensioned high-strength steel bar (so-called PC bar) was proposed by Yamakawa and Kurashige et al., and it was verified that the seismic performance of poor RC column could be improved by using this seismic retrofit technique. However, axial compression behavior of RC column confined by pre-tensioned PC bar has yet to be investigated. In this paper, results of axial compression tests of RC columns with active and passive confinement are described at the first phase, and then, Sakino & Sun's stress-stain model of confined concrete is modified in order to evaluate experimental results appropriately.

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Dynamic and static loading tests were conducted to evaluate the seismic performance of reinforced concrete exterior beam-column joint at the lower story of high-rise buildings. Eight sets of two specimens each with the same dimensions and details were prepared for the dynamic and static tests. Variable parameters of these specimens were three, that is, (1) ratio of the ultimate shear strength of the beam-column joint to the bending yield strength of beam, (2) anchoring method of main reinforcements of beam: mechanical anchor and U shaped anchor, (3) axial load of column: constant axial load and fluctuating axial load. Influence of loading rate increase on the failure process, ultimate strength and deformation performance was investigated, comparing the dynamic and static test results under various conditions.

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In this paper, we aim to clarify the bond behavior between EC (Epoxy Coated) strands and cement grout through the experiments, and propose the estimation method for the tension force (P)-displacement (⊿) relationship. EC strands are rust proofing PC strands coated with epoxy resin. This paper represents the pulsating pullout tests of EC strands with cement grout encased in PC beam. The 4 parameters are established; the number of EC strands arranged in steel sheath, the compressive strength of cement grout, the initial prestressing tension of EC strands, and with or without steel sheath. Pulsating pullout tests of PC deformed bar and PC strands are also carried out in order to compare with EC strands. The following conclusions were drawn from the study. 1) The bond strength of EC strands is smaller than that of PC deformed bar. The bond stress is almost constant throughout the transmission surface. During unloading, the bond stress near the end of beam is produced in opposite direction indicating same magnitude under loading. 2) The bond surface of EC strands in the case the 3, 5, 10 strands arranged in steel sheath is evaluated multiplying a bond surface of 1 strand by the number of strands. 3) The compressive strength of cement grout, the epoxy resin coating, the initial prestressing tension and the steel sheath have little influence on bond behavior between PC strands and cement grout. 4) The P-⊿ relationship could be estimated with proposed method.

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The seismic behavior of structural steel members are influenced significantly by the difference of material properties. Therefore, it is very important to clarify the correlation between material properties and structural behaviors. In this paper, FEM analyses are conducted to consider the influence of material properties on the rotation capacity of the beam-to-column connections. The equations that can evaluate the rotation capacity quantitatively are proposed. These equations are not only considering local buckling but also fracture at the beam end. Finally, the regions of the width-to-thickness ratio, collapse mode will be defined by fracture, are proposed.

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In this paper, a simple column base system in steel structures is experimentally studied. The column base is encased by filling steel fiber reinforced cementitious composites. In the test, cantilever column specimens are adopted for the basic and applied models of the proposed system and also the ordinary embedded column base, and cyclic load is applied. The results show that the applied model gives enough stiffness, strength and ductile hysteresis characteristics in comparison to the ordinary column base, and also the basic model gives relatively stable hysteresis characteristics for the limit drift ratio of 0.01-0.02 (rad).

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This paper clarifies the influence of web deformation on the flexural buckling load of H-shaped compression members with eccentric braces at the center of their length axis. In the previous papers, it is assumed that the web deformation of the compression members is restrained in order to have the stiffeners at their joint between braces and members, but a form of joint becomes complicate and constructive efficiency decrease. In this paper, the buckling load is developed by the energy method and confirmed by the elastic eigen-value analysis, and the rigidity demand is evaluated using inelastic large deformation analysis.

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The authors conducted static loading tests on src exterior beam-column subassemblages using mechanical anchorages to investigate the collapse behavior and the structural performance. Test results showed that it is possible to evaluate the anchorage strength of beam longitudinal reinforcement and the shear strength of beam-column joints in the same methods as r/c structure. Besides, the design criteria based on the evaluation methods is suggested in order to give src exterior beam-column subassemblages large deformation capacity.

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Authors have proposed the risk quantification method for a portfolio of buildings, in which the risk reduction effect by diversifying the buildings is given assuming that the variability in the ground motion intensity in each site is fully correlated. Since this assumption gives the conservative results, it is required to obtain the realistic value from the viewpoint of risk management. Recently, large amounts of earthquake observation data have been utilized, so that the spatial correlations of ground motion intensities in the different sites can be calculated. In this paper, abovementioned correlation in the Kanto district is obtained using K-NET and KiK-net data, and is applied to the model portfolio of the buildings, followed by the conclusion that introducing the correlation has a large effect on the estimated losses.

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