It is important to grasp the thermal properties of concrete including creep of concrete for preventing cracks of reinforced concrete members subjected to repeated thermal loads. Some experiments were conducted using cocrete specimens under constant compressive stress subjected to temperatures up to about 80℃ at slow heating and/or cooling rate to evaluate thermal strain including transient thermal creep. From the experiments, the following conclusions were derived: 1.The influence of transient thermal creep was most remarkable at the very first-time heating for the concrete, though the influence at the repeated heating and cooling phase of concrete was little. 2.A new coefficient of thermal expansion including transient thermal creep can be formulated by both the heating rate and the applied compressive stress ratio of concrete.

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This paper deals with the influence of aggregate properties on concrete drying shrinkage. Drying shrinkages of concretes with various types of aggregates were measured and relationships between the fundamental properties of aggregates and the shrinkage strains of concretes were investigated. Furthermore, specific surface areas (S.S.A.) of aggregates were measured by moisture sorption isotherm tests up to 32.5%R.H. Drying shrinkages of concretes with various kinds of aggregates increased with the increase of the S.S.A.s of aggregates. The test results indicated that the S.S.A. will be an effective index for evaluating the influence of aggregate on the drying shrinkage of concrete.

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Carbonation depths of fly ash concrete and non fly ash concrete in outside environment at 30, 65 and 100 years are predicted by 3 methods named √t law, b power law and b_0 power law, based on carbonation data collected from proceedings and journals which published from 1979 to 2005. Carbonation progress shape coefficients, b in the equation of x=At^b (x: Carbonation depth, t: Term, A: Carbonation rate coefficient) are analyzed, and the convergence values, b_0 of b are determined. The b_0 of fly ash concrete exposed outside in a long term is about 0.37, lower than that cured in accelerated condition, 0.47, and is also lower than the b_0 of non fly ash concrete exposed outside, 0.47. The relationships between predicted carbonation depths and compressive strengths of fly ash concrete and non fly ash concrete are investigated, with the result that to control carbonation depth less than 40mm, extra strength of 3N/mm^2 is required for durability design of fly ash concrete than non fly ash concrete.

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A 45-story RC building, where pre-cast concrete members were employed for its outer frame as well as inside columns and beams, were construction, and the estimate equation of the operation standard time was examined with its construction data. As a result, the following conclusions were obtained. 1) In this measurement, the installation time of the pre-cast member in the top floor has decreased to 39.4〜63.8% compared with that in the floor. 2) In the construction of the high-rise RC building, the reason for the reduction in installation of the pre-cast column and the pre-cast beam from a lower floor to the upper depends on both the improvement of worker's capability and the change in the work difficulty. 3) The change in the total mean operation time by repeating work in high-rise RC buildings can be estimated with the logarithm model of the learning engineering. However, it is necessary to consider the change in the work difficulty for evaluation of the installation time of pre-cast members in high-rise RC buildings.

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The study on the influence of mix proportion of high strength concrete on the segregation of coarse aggregate and sludge formed during centrifugal compaction is reported here. First, the influence of mix proportion conditions, such as the type of superplasticizer and silica fume used and the water cementitious material ratio, on the rheological characteristics of high strength concrete paste was studied. Next, experiments were conducted on sludge generated while mixing various kinds of materials during the centrifugal compaction of high strength concrete. The results of the experiments showed that the plastic viscosity of paste increases as the water cementitious material ratio decreases. Moreover, the dewatering effect decreases, and sludge does not form easily. It was verified by measuring the quantity of sludge generated and by analyzing the cut surface of the centrifugal compaction test specimens that the smaller the quantity of high strength concrete paste, the more effective is the generation of sludge and the segregation of coarse aggregate.

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A penetrating needle into a membrane was first developed on the basis of the observation of bamboo grass tips and lawn grass tips. Then, the penetrating load of the needle was measured for various waterproofing membranes at the needle displacement speed of 1mm/min. These two types of grass were also planted in the containers, inside of which the waterproofing membranes were applied. After the rearing of 1 year, the membranes were inspected. The two results of each membrane type were compared. We were interested in the maximum strength and the strength at 1mm displacement. These values are considered to be useful as indices for the estimation of the waterproofing membranes' root resistance.

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The purpose of this elaboration is to investigate the carbonation resistance of waterproofing membranes applied to the concrete surface, particularly the cracked zone of the underlying concrete. The considered parameters were, the width of the crack in the concrete, the presence or absence of the waterproofing membrane, and the membrane thickness. Mortar prisms shaped specimens were coated by two types of the fluid waterproofing membrane. The prisms were cracked by bending and then exposed to an accelerated carbonation environment with an atmosphere of 10% carbon dioxide. After 1 year of exposure in this environment, the depth of carbonation was measured. Carbonation areas were observed along the cracks of the specimens with thin coatings along the wide cracks. Furthermore, a numerical simulation method was developed on the basis of diffusion theory and the carbonation at the cracked area of the concrete was simulated.

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The sealants for construction used for the exterior of buildings deteriorate with progress of time, and cracks generate on the surface of them. Although crack is an important failure which grasps the state of degradation, sensuous evaluation by visual observation has mainly been performed until now. In this study, the new quantification method which is based on fracture mechanics is proposed for estimating damage of sealants. By this quantification, we can compare the difference in the cracks of sealants exposed for various periods and in various exposure sites.

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In order to apply a nondestructive inspection method for estimating compressive strength of concrete using impact-elastic wave velocity to high strength concretes, the studies were carried out on some influence factors to the elastic wave velocity. This paper described experiments conducted on cylinder specimens and column modeling specimens, and clarified the compatibility of correlation between elastic wave velocity and compressive strength in high strength concretes with the strength estimation formula and validity of compressive strength estimated from the measurement velocity of elastic wave.

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This research clarified the characteristics and the troubles of the actual house renovations for the purpose of preventing nursing care and arranged the urgent problems should be coped with. As the result, "bathrooms" was extracted for one place that had the largest number of cases taken in and the particularly high incidence of dissatisfaction. We made a comparative study on the effect of three factors-shape and position of handrail, height of toilet seat, C.S.R of floor-that were taken to support standing up and sitting down movements in the bathrooms. Through the examinations by means of three dimensions motion analysis, we proposed an estimating method with the objective evaluation index for the aged to judge the effect of each house renovations' means and to adopt the appropriate steps easily.

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The purpose of this paper is to investigate the effect of the roughness of the ground surface on the flow around a 3D steep hill in boundary-layer turbulence by LES analysis. First, we confirm that the present LES method with very small numerical dissipation can simulate the flow around a 3D steep hill with smooth surface of the ground in boundary-layer turbulence. Next, we introduce roughness blocks which are modeled by Goldstein's immersed boundary method, and then validate the present LES method about the roughness effects on the flow characteristics around a 3D steep hill through the comparison of the computational results with the experimental data. Finally the effects of the roughness of the ground surface on the wake structure of the 3D steep hill are discussed by use of the computational flow visualization technique.

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The purpose of this study is to develop attenuation relationship for acceleration response spectra on engineering bedrock for predicting strong ground motion. For developing the attenuation relationship, 3198 strong motion data from 52 earthquakes, which occurred in and around Japan from 1978 to 2003, with monent magnitude 5.5 to 8.3 are compiled in a database. By performing regression analysis using maximum likelihood method, new attenuation relationship is developed. In this relationship, effects of focal depth on the ground motion intensity and the focal depth dependence of the geometrical spreading coefficient are considered. The results show that the earthquake with deeper focal depth generates stronger ground motion.

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This paper discusses a vibration control performance of inelastic damping devices installed in a building structure under a large earthquake. It is commonly believed that the plastic deformation due to material yielding has large energy dissipation capacity as well as large damping effect on the system response just like linear viscous dampers. This paper proposes a mathematical model that depends on the feedback control theory and modern control approach to verify the damping augmentation instead of an ordinary model commonly used in the civil engineering. The author discovered that we could expect as much damping augmentation from inelastic dampers as from ordinary linear viscous dampers, but the damping effect itself is far less than we expected from a classical dynamic model. Further discussion is definitely necessary until we make a reasonable engineering decision as to which model is better to describe the real dynamics of the structure.

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Dynamic loading tests on one bay-three story steel frames installing a stud column with a viscoelastic damper are conducted to investigate the dynamic behavior of the frames and the effect of response control by the damper. A total of six frames are tested with different damper arrangement and loading speeds. Differences of the stiffness, damping properties and story drifts between stories with and without the damper are discussed. It is found that the rotation at the center of beam where the damper attaches significantly affects the behavior of the whole frame and the damper.

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The objective of this paper is to establish criteria using which one can predict the story where plastic drift dominates in two-story steel building under strong ground motion. The dynamic response analyses were conducted for Elasto-Plastic and Rigid-Plastic models. The following conclusions are obtained for the response of Rigid-Plastic model. 1) If the shear coefficient of the 2nd story exceeds the base shear coefficient, the plastic drift occurs only in the 1st story. 2) Otherwise, the plastic drift occurs also in the 2nd story. The story of which plastic drift dominates can be predicted considering the story shear coefficient, the peak ground acceleration and the mass distribution of structure as shown in Fig. 12. Similar conclusions are obtained for Elasto-Plastic model if the story shear coefficients are small enough.

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This paper proposes a fast and sufficiently accurate algorithm for calculating fractional time-derivatives of stress and strain in the viscoelastic damper. The algorithm also has an advantage of requiring substantially smaller memory space. At every step, numerical integration using past stress and strain data is required, but the proposed algorithm needs only a small portion of such data: it selects and stores the data at much longer interval than the original algorithm. The algorithm is applied to two types of viscoelastic damper models, which are "short duration model" and "long duration model". Its numerical efficiency and accuracy are demonstrated through comparison with the original and precise algorithm.

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This paper shows two methods of reducing from a single-story asymmetric building under uni-directional earthquake motion to the equivalent single degree of freedom system (ESDOF) to improve the capacity spectrum method used in the calculation of response and limit strength provided in the Building Standard Law Enforcement Order of Japan. One is the static reducing method with mode-adaptive pushover analysis and the other is the dynamic reducing method using modal decomposition procedure together with earthquake response analysis. Applying both methods for four types of single-story RC buildings with different eccentricity, the validity of the methods and the earthquake response characteristics of ESDOF system are examined. Based on the latter method, an evaluation method of the higher mode effect in story responses is also proposed.

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Theoretical studies are presented on the elastic behavior of a high-rise building with shear walls using elementary beam thory. The shear wall is modeled to a bar subjected to bending and shearing deformations, and moment resisting frames are approximated as beams subjected to shearing deformations. The shear wall and moment resisting frames are coupled by connecting beams. Deformations are obtained as the solution of ordinary differential equation. The influence of the connecting beam rigidity to the deformation of the system can be investigated by simple tools like the spread-sheet software. The bending deformations of the braced wall of steel structures are reduced by the restraining trusses, so called Hat-Truss or Belt-Truss. Effects of restraining trusses are also investigated.

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The author has studied the time domain evaluation of the frequency dependent impedance, and has proposed some transform methods. In this paper, the the time history response analysis method of the dynamic stiffness with both frequency and strain dependency was studied. The frequency dependent complex stiffness was calculated at each strain level first, then they were transformed to the impulse response in the time domain. The characteristics of the complex stiffness and the impulse response of both 2-layered soil and the viscoelastic dampers were investigated as examples. Then the time history response analysis method considering both frequency and strain dependency using the impulse response of each strain level was proposed and the example analysis of 2-layered soil was shown.

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Effects of adjacent building on soil-structure interaction of pile foundation, piled raft foundation and embedded foundation on pile group are studied by the thin layered element method combined with flexible volume substructure method. The Homogeneous soil and two-layered soil are considered to simulate friction pile and bending pile. The effects of the adjacent building on the impedances and foundation input motions are analyzed and compared with those of spread foundation. The bending moments and shear forces in piles are also examined and the results show that the effects of adjacent building on the stress in the adjacent piles of two pile foundations or piled raft foundations are prominently.

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75 cases of damage to building foundations, most of which are pile foundations, are arranged according to building or ground natural period estimated from building height or soil profile respectively in the area of the Hanshin-Awaji quake disaster. In the first place, it is shown that the estimated natural period of building T is consistent with long period, _LT_e calculated from 26 detailed samples which contain informations on rigidity and mass of the buildings and that the short period, _sT_e corresponds to 0.6T. Reclaimed land is separated from other soils at 0.3 or 0.4 sec. of estimated ground period, T_g. There are many cases of damage to foundations in the period of 0.4T<T_g<_LT_e in alluvial fans of "Disaster Band". In the period of T_g<0.4T, building skeleton damage is found. Those building periods are 0.6sec-0.9sec. T_g=0.4T is characteristic line. There are typical cases of damage according to ground slip in hills and damage to piles according to liquefaction and flow of soils in reclaimed land.

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This paper presents the results of two lateral loading tests on the actual caissons of the same size, which were constructed about 40 years ago, as well as the results of corresponding numerical analyses. In the tests, much focus was placed on the proportion of the lateral resistance between the side friction of the caisson and the passive soil resistance. The test results show that the proportion of frictional resistance to the total resistance is relatively large, and the evaluation of the friction is important. Numerical analyses were also conducted to examine the applicability of the conventional non-linear method. The caisson behavior obtained from analyses give reasonable agreements with the measured results, if adequate coefficients of lateral subgrade reaction are chosen.

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Fire resistance of prestressed concrete beams in terms of flexural capacity was investigated. High strength steel such as prestressing steel has a different strength reduction curve under high temperature from ordinary strength steel. The authors conducted tensile tests on prestressing steel bars under high temperature up to 600 degree Celsius. It was revealed from the test results and past research that BS8110 with some modification in the lower temperature range gave a good estimation for strength degradation of prestressing steel bars at elevated temperature. Temperature contours in the beam cross section of a prestressed concrete member was derived based on a simplified equation. The contours agreed well with the one obtained experimentally in past research. Design recommendations for prestressed concrete beams at elevated temperature are included in this paper.

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About the thesis, we did the welding construction experiment by using two kinds of examination bodies with different shape of the real scale and the butt joint. In addition, we examined the influence that the difference of the material shape gave to strength of the weld metal by using three dimensions finite element method analysis. Consequently, the following findings were obtained. It could be possible to presume the strength of weld metal from heat input, interpass temperature, mill sheet value of welding wire, and material shape. The cooling time of the weld metal is influenced form the heat input, interpass temperature and the volume of the material, and we can presume the cooling time from these results. Carbon equivalent of the weld metal receives the influence by the heat input, and we can presume carbon equivalent of the weld metal from chemical component of welding wire and the heat input.

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The authors developed a sustainable building structure system with a primary goal of extending the service life of the entire structure system and a secondary goal of permitting the reuse of structural members if the primary goal cannot be attained. In this paper, a mechanical model is established based on the mechanical properties of the beam-to-column connection tests revealed by the authors' past experimental studies. The mechanical model is compared with the results obtained from beam-to-column connection in detail. The model is further compared with the results from partial frame testing in which buckling-restrained braces are attached to beams and columns like knee braces. The findings obtained from the comparisons indicate that the mechanical model has satisfactory stiffness and strength, and accurately demonstrates the behavior of the beam-to-column connection. Thus, the effectiveness of the model has been proven. The authors believe that the mechanical model is applicable to analysis of the entire structure system.

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The autors have clarified the buckling strength of the compressive plate section member with eccentric lateral support by theoretical and numerical analysis. This paper presents the loading test of compressive plate section member with eccentric lateral support. The results of the experimental buckling strength and buckling shape are coincident with the proposal value and the proposal shape in the previous paper. The eccentric lateral support for plate-section column has equal effect to support whole section. This paper also discusses the bracing force of support member compared with the design recommendations.

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The bending moment resistance of the column bases decreased seriously during overall drift angle 1/15rad loading, because of the fracture of the anchor bolts in tension side and the crash of concrete placed under the base plates in compression side. The inflection point of first story columns moved to lower by column base moment resistance decreasing and increased the bending moment at the first story column top. In result, local buckling occurred at the first story column top and formulated the first-story collapse mechanism. The first story shear decreased significantly with the increase in story drift angle from 1/20 to 1/8rad, while the second story was unloaded.

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In the authors' previous paper (part 1), critical response analysis method was modified to be able to consider the influence of the loading history, and its unified formulation for the steel frame structure was presented. Also, in order to verify the validity of the new method, elasto-plastic and finite deformation analyses of the steel brace member subjected to repeated prescribed axial displacement were carried out. In this paper, parametric studies of the steel brace member are carried out with changing the slenderness ratio and the amount of the prescribed axial displacement. Both the ordinary and the modified critical response analysis methods are employed in the parametric studies, which enables us to see the influence of the loading history. It is discussed how those three factors (slenderness ratio, amount of the prescribed axial displacement and the loading history) influence on the behavior of the steel brace member, with attending to the skeleton curve and the steady-state hysteresis curve.

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Shear friction between the base plate and base mortar contributes to the shear resistance of standard column bases. A value of 0.5 is adopted for the coefficient of shear friction in AIJ's design specifications, but the associated background data and theory is limited. Cyclic loading tests load and surface roughness as major parameters, twice as large as the coefficient expected for unchanged for slips that succeed the initial slip. A combined theory of adhesion and plowing, originally developed for friction between steels, is applied to interpret the friction behavior steel and mortar, indicating reasonable correlation with the corresponding test results.

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This paper addresses the derivation of collapse load of rectangular hollow sections (RHS)-column to beam connections with exterior diaphragm based on the method of plastic analysis. The presented formulae are available for arbitrary shapes of exterior diaphragms, and include the influence of weld details between the diaphragms and the column. In order to verify the validity of the collapse load, tests of the connections were performed. Major findings from the tests are summarized as follows: (1) the yield strength obtained from the tests was about 70 to 80% of the collapse loads, (2) there were 14 to 45% differences between the experimental maximum strength and the calculated maximum strength, (3) the experimental maximum strength of specimens which were expected to fracture in the fillet weld between RHS-column and exterior diaphragm agreed well with the calculated maximum strength, and (4) the assumed collapse mechanisms agreed well with the ultimate states of the connections.

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