This study discusses the drying shrinkage and the carbonation of Ecocement with ground granulated blast-furnace slag, as compared with those of Ordinary portland cement with ground granulated blast-furnace slag. As a result, The drying shrinkage of Ecocement with ground granulated blast-furnace slag had become small, as compared with that of Ordinary portland cement with ground granulated blast-furnace slag, in case of ground granulated blast-furnace slag 50% mixture. The carbonation of Ecocement and Ordinary portland cement with ground granulated blast-furnace slag was increase, but the increase ratio of carbonation when ground granulated blast-furnace slag was mixed was different in Ecocement and the Ordinary portland cement.

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Hydration process of many kinds of cement paste is investigated by Powder X-ray diffraction (XRD)/Rietveld analysis. The parameters of the present study are type of cement (ordinary Portland cement, low heat Portland cement, and Eco-cement), water to cement ratio (0.50, 0.35), and curing temperature (283, 293, 313K). In this contribution, reaction of alite and belite is focused and evaluated. Experimental results show that the reaction of alite is affected by the temperature, but the effect of W/C is rather small. Regarding belite, its reaction is strongly affected by the reaction of alite and temperature. The hypothesis, in which rate of reaction of belite is explained by the ion concentration of CaO and SiO₂ in the capillary water and solution equilibrium curve of alite, belite, C-S-H and Ca(OH)₂, is proposed. Based on these experimental facts, simple hydration model is proposed.

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This paper presents the impression of the workability of plastering materials evaluated by the skilled plasterers. The sensory test using the cement mortars based on various mixture proportions was carried out in order to obtain fundamental information. The fourteen evaluation items such as viscosity, softness, and tired feeling which might be related to the workability of plastering materials were prepared for the sensory test.
As a result, it was found that the plasterers could react to the differences of mixture proportions sensitively, moreover the ease of troweling and finishability are strongly related to the workability of the plastering materials.

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Compressive strength of concrete is usually corrected to predict so called true uniaxial compressive strength when the value is measured with specimens having height/diameter (h/d) of less than 2.0. As long as porous concrete is concerned, however, sufficient data is not obtained so far for the correction of the compressive strength. In the present study, a series of experiments was conducted to clarify the degree of influence of h/d ratio. As a result, it has been made clear that almost the same correction formula can be used for porous concrete as normal concrete. The proposed formula can be used also for core specimens from porous concrete structures to predict the relationships between the compressive strength and h/d of a specimen, as well as standard cylindrical specimens cast in molds.

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This paper describes the effect of deterioration of surface coatings applied on polyurethane membranes due to weathering, to carbonation of cracked concrete substrate. The specimens with various thicknesses of membranes, which were stretched at the crack of 1mm wide of concrete beams, were exposed outdoors in Yokohama for 5 years. Carbonation area in cracked zones of the specimens was observed. On the basis of the observation, a numerical simulation method that is considered the influence of degradation of surface coatings and membranes was developed. It was made clear from experimental and analytical studies that carbonated area of cracked concrete increased according to deterioration of surface coatings.

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The pressure test and the wind tunnel test were carried out to obtain basic data for wind resistance design method of a mechanically anchored waterproofing membrane system. The test specimen was a flat roof with dimensions; 2.4m-wide, 3m-length and 0.29m-height. The waterproofing material was polyester fiber-reinforced PVC sheet. In pressure test, because the applied pressure is equivalent pressure on all area of the roof, the billowing height of PVC sheet around fastener were almost same values. Therefore, the vertical force at fastener was also same with the pressure induced by a compressor and horizontal force was approximately 0N. On the other hand, the strain of PVC sheet around fastener at windward was larger than that of leeward in the wind tunnel test. Then, the horizontal force was 70% of vertical force at mean wind speed of 38.6 m/s. Therefore, it was clear that characteristic of mechanically anchored waterproofing membrane system in pressure test and wind tunnel test was different.

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On the basis that cement concrete are used in various life cycle stages, we examined the leaching tests. In the case of using ordinary Portland cement, the leaching amount of hexavalent chromium was influenced by total chrome content and chemical component and the amount was decreased with the hydration. On the other hand, carbonation was found to cause the decomposition of cement hydrates and the release of fixed hexavalent chromium. Moreover, in the case of using Portland blast-furnace slag cement type B, the hexavalent chromium hardly leached, due to reduction action of blast-furnace slag.

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We estimated the fault of the 1924 Tanzawa earthquake (Mj7.3), which was the largest aftershock of the 1923 Kanto earthquake (Ms8.2). We could successfully reproduce the observed waveforms in central of Tokyo based on the estimated fault model. This is very important to investigate the characteristics of ground motions by M7 events occurring in the Tokyo Metropolitan area because we only have a few observed waveforms of such events in central Tokyo. Finally, we calculated ground motions around Tokyo metropolitan area by the estimated fault model. The simulated ground motions do not exceed the design spectra around the area but in west of Kanagawa Pref.

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It is suggested that the pulse-like ground motions, in the near-fault region, have great impact on the building seismic design. However, the theoretical study on the building response to the pulse-like ground motions input is not sufficiently clarified yet. In this study, the time at maximum response is theoretically evaluated as important factor. Based on that, the theoretical solutions of response spectra, with single-degree-of-freedom system subject to the sinusoidal pulse input, are performed. In addition, we suggested the damping-modification-factor, in accordance with the time at maximum response and the pulse wave period - building period relations.

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We examined how the relationships systematically change among the moment magnitude M_W, the Japan Meteorological Agency magnitude M_J, and the short-period magnitude m for inland earthquakes classified by fault type. The examination was extended to the relationships among the magnitudes for inter-plate earthquakes and to those for slab earthquakes. It was found out that M_J was about 0.5 larger than M_W in inland earthquakes caused by strike-slip faults, M_J was about 0.2 larger than M_W in inland earthquakes caused by dip-slip faults, m was about 0.2 smaller than M_W in inland earthquakes caused by strike-slip faults, and m was about 0.1 larger than M_W in inland earthquakes caused by dip-slip faults. We applied these relationships to the procedure for evaluating fault parameters, and showed two examples of strong motions predicted for strike-slip and dip-slip faults 40 km long.

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We discuss the earthquake energy input to (absorbed by) a structure with rotating inertial mass dampers (RIMD). First, an SDOF model is studied by comparing the energy absorbed for a white noise input. The amount of energy absorbed by the overall system is reduced when an RIMD is installed in parallel with a structural stiffness, but is unchanged when installed in series. Next, the dependence of reduction rate on RIMD arrangement is evaluated by examining the energy absorbed in an MDOF model for a white noise input. Finally, based on the energy spectrum and the above reduction rate, we confirm the validity of evaluating the absorbed energy using a three-story vibration model, by comparing the energy absorbed for an earthquake input.

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Typical steel moment-frame structures in the United States comprise a few seismic frames and many gravity frames, which include “continuous columns” that are pin-connected to beams. These continuous columns, which are often ignored in seismic design, can improve the seismic performance of the structure. This study investigates the effects of continuous columns on the structural stability and seismic response of building frames. Stability coefficients representing the separate and combined effects of geometric and material nonlinearities are used with a simplified modeling technique, which separates the shear-type and flexural-type lateral-force-resisting systems in moment frames. Relationships between continuous column stiffness ratio and the stability coefficients, inter-story drift, and the drift concentration factor are presented. It is shown that for realistic structures, the columns in the seismic frames are generally sufficient to prevent unstable response and large drift concentrations, and the inclusion of gravity continuous column stiffness tends to decrease both the drift concentration and inter-story drift.

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Maintaining various city functions during an earthquake is very important. However, the concrete earthquake measures method to preserve function of important facilities which constitute these city functions has not been advanced. We are focusing hospitals as the important facilities aiming to improve its seismic performance. Shaking tests for a full-scale four-story reinforced concrete specimen assuming a hospital including real medical facilities and equipment were conducted. The specimen was installed as a seismic-resistant or a seismic isolation structure on E-defense and shaken with short-period and long-period earthquake motion, respectively. The function in the seismic-resistant structure dropped significantly against the short-period earthquake motion. On the other hand, the seismic isolation structure exhibited immensely-high functional retention capacity against the short-period earthquake motion. But in the case of the long-period earthquake motion, serious damage in the function was confirmed.

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Vicso-elastic dampers are increasingly used to reduce earthquake-induced vibration of building structures, including wood house structures which show slip hysteresis under earthquake loading. In this paper, simplified theories are proposed for seismic response evaluation and preliminary design of slip-hysteretic structures combined with visco-elastic dampers. They are based on the single-degree-of-freedom (SDOF) idealization of multistory structure, and produce the control performance curve expressing the peak responses as a function of stiffness of all components, based on spectral characteristics of the earthquake. Against the target peak response, a rule to convert the SDOF design to multistory design, with consideration to distribute damper stiffness over the height of structure, is also presented. Accuracy of the approach is demonstrated by time history simulations over a wide range of parameters.

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A new and effective hybrid stress 2D finite element based on the plane beam-column theory considering higher order shear deformation and the bi-axial effect in stresses and strains was developed, in the previous papers. In this paper, the availability and applicability of the present 2D finite element, for the walls and/or the portal frames with the wall elements, are discussed and examined. The behavior of the wall with a square opening are analyzed and are compared the photoelasticity experiment results by Tokuhiro etc. Also, the parametric studies on the size of square opening or the size of boundary column are performed, and might specify their influence and effect on the responsive characteristics of the wall with an opening.

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This paper discusses the stability of laminated rubber bearings with high damping materials both theoretically and experimentally. The specimens adopted for this study were tested under static loading before shaking table tests were conducted to check their dynamic stability. As a result of the static loading test we have obtained the fact that the geometrical nonlinearity can be separated from the material nonlinearity under large deformation. The shaking table tests also support the stability criterion that is predicted from the geometrical nonlinear theory, which has been proved by the static loading tests in the previous studies. This paper successfully explains the coherence between the experimental results and the theoretical predictions expected from the rigorous solutions based on the nonlinear model we have developed in the previous study.

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In this study, the main purpose is to form an understanding of the ground motion caused by an earthquake through pseudo dynamic tests which are then evaluated from the viewpoint of the energy balance concept. The following points are made clear in order to demonstrate the possibility of estimating the ground behavior during an earthquake by the energy concept proposed in this paper. 1) All of the energy input into the saturated sandy ground exerted in an earthquake is consumed by ground deformation. Therefore, the energy input is equal to the accumulate plastic strain energy. 2) There is a strong relationship among the excess pore water pressure, the ground deformation and the accumulate plastic strain energy. 3) In regards to the effective natural period of the ground, the energy input can be evaluated by the energy spectrum.

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The correlations between the degree of saturation (Sr) and P-wave velocity (Vp) and between the degree of saturation and liquefaction strength (R_l) of in-situ sandy soils were investigated based on the P-S wave logging test results and laboratory test results using high quality undisturbed sand samples recovered before and after soil improvement performed by sand compaction pile method. The effects of the confining stress and relative density on Sr-Vp and Sr-Rl correlations for in-situ sandy soils were also investigated.

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To investigate effects of pile rigidity on response of a base-isolated structure and pile stresses during soil liquefaction, dynamic centrifuge tests were performed on a superstructure-footing model supported by 2x2 piles. Additionally, the shear deformation of the seismic isolator was investigated by analysis of SDOF systems. The following conclusions were reached: (1) The shear force at the pile heads and their tips of the low rigidity piles was smaller than that of the high rigidity piles. (2) The shear deformation of the seismic isolator supported by the low rigidity piles was larger than that supported by the high rigidity piles.

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Three-point bending tests were performed for beams made of Japanese cedar, in which the beam axis is inclined to the grain of the wood. Followings were observed with respect to the cracking path. Splitting starts at the point on the tension edge where the stresses satisfy the fracture criterion for orthotropic plates. When the beam is not restrained, in other words, the beam has an entirely free path of cracking, the crack suddenly propagates into the compression edge, resulting in the total failure of the beam. However, when plywood panels are attached to the sides of the beam in its half span in order to interrupt the anticipated cracking path, the splitting crack stops on its way and then bending failure is developed slowly. The first splitting, even when the cracking path is interrupted, can be initiated only if a small trigger length equivalent to the interval of annual rings is latent in the possible cracking path. From fractography by means of SEM, it was found that the initial crack of splitting is the fibrous crack with honeycomb patterns, which is followed by the progressive crack with split bamboo patterns.

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We have developed the new earthquake resisting wall which made KAGOME-knits of the bamboo material. This study proposes the tensile properties of the bamboo material for crafts used as the material. Full-size tensile tests were conducted in order to examine the tensile character of 162 tensile specimen. And the correlation of thickness(t) of a node and a internode, and tensile properties was mainly examined. Main findings are given in the below. First, very strong linear relationships are observed between breaking strain and failure modes. And the difference of the thickness of right and left of a node had influenced the failure modes. Second, strong linear relationships are observed between tensile properties and t. Therefore, the stress grading based on t was examined as a next phase. As a result, it was found that it was effective. From these results in the above, the bamboo material, of which quality is controlled by the present method, is available as structural bamboo, since stiffness, strength, and maximum load are guaranteed.

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In this study, to evaluate the influence of PΔ effects on the deformation performance of wooden house, the static lateral loading test to the large deformation region of the wooden frame structure is performed to the collapse. It is pointed out that the ratio of the bending deformations of column in the story drift angle is not so large, the additional shear force by the PΔ effect can be explained from the story drift angle in the experimental results. Finally, we propose the method to estimate the story drift angle when the lateral resistance force is lost from the story shear coefficient in the large deformation region (story drift angle is between 0.1 and 0.15rad).

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To improve the prediction of nonlinear response of RC buildings to the design input ground motions by the equivalent linearization method, a simple equation for the asymmetry of response is proposed based on the assumption of equal energy response in the positive and negative direction. Then, an equivalent linearization method considering the asymmetric steady state response by the proposed equation is introduced in this paper. The method shows excellent agreement with the results of the time history response analysis of a single-degree-of-freedom system with Takeda's hysteretic characteristics.

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This paper is presented about seismic retrofit methods for existing concrete columns with steel plate combined with aramid fiber sheets subjected to axial load. The component of steel plate does not require any welding on site. In place of welding, aramid fiber sheets applied over the entire exterior surface of the steel plates by continuous rolls, provide the necessary binding of the steel plate components in addition to providing its own structural contribution. The purpose of this study is to examine the lateral confinement effect. Also theoretical formulas, derived from the model of compressive strut, were proposed to evaluate the compressive behavior.

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This paper presents an experimental study on the buckling-restrained brace (BRB), in which round steel bars and double steel tubes are employed for core members and buckling-restraining members, respectively. The inner tube restrains buckling of the core members directly and the outer tube restrains buckling of the inner tube through the spacers. The core member of round steel is divided into two bars, and they are connected with a central coupler. The outer tube is connected to the central coupler by welding for preventing the outer tube from falling by self-weight. This bracing system has plural contraction allowance parts permitting the plasticity contraction of the core member. The authors carried out the element tests of the core member, and also carried out the full-scale cyclic loading tests of the brace. The test results revealed that the proposed BRB has sufficient capability as a hysteretic damper under the control of the compressive axial force by the number of contraction allowance parts and the fixing methods of inner tubes.

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