Adsorption and desorption isotherm model of hardened cement paste under 20 °C is proposed. Adsorption and desorption isotherm of hardened cement paste with different water cement ratio, temperature history, and different degree of hydration were experimentally studied. Based on the experimental data, following characteristics were derived: 1) BET surface are of adsorption process and desorption process has linear relationship, 2) Relationship between statistical thickness of adsorption and relative humidity is identical in the range below 40%RH, 3) t-curve can be derived from the relationship between statistical thickness of adsorption and relative humidity, 4) difference between statistical thickness of adsorption and t-curve has a linear relationship between Kelvin radius, 5) virgin desorption curve value less than 40%RH has similar value of those of desorption curve after drying pre-treatment, 6) virgin desorption curve has a linear relationship with relative humidity. Based on these experimental points, empirical adsorption model is proposed.

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In this study, the effect of variation of the grading of fine and coarse aggregate within the range specified in JIS on the fluidity, viscosity and segregation resistance of fresh concrete was investigated. Additionally, the effect was considered based on the excess paste theory. The following findings were obtained as the results. (1) The variation of grading of fine aggregate has a great effect on the fluidity and the segregation resistance of concrete. On the other hand, that of coarse aggregate has a relatively small effect on these properties. (2) The effects mentioned above can be theoretically controlled based on the distance between each aggregate in dispersion. (3) The fluidity of concrete is dominantly affected by the properties of aggregate such as grading. On the other hand, the viscosity of concrete is greatly affected by the properties of cement paste.

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When the average thickness of additional cover concrete in design phase and that in construction phase are separately analyzed for each type of member such as column, beam, etc., it showed an almost normal distribution, respectively. Furthermore, concerning the relationship between distribution of the average cover concrete thickness on each measuring face of any member and the deviation within a member, a tendency was found that the deviation within a member increases along with an increase in the average value while the former remains small as far as the latter is small.

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In the building structure field, welding robots have been used since the latter half of the 1980s. Today, a large number of robots are used mainly for in-factory welding of column components.
As for steel frames of buildings, the welding of single bevel T-joints with steel backing is usually used. Recently, there have been some experimental reports concerning a 25-degree groove welding by semi-automatic arc welding.
In the report, the authors demonstrated the relationship between groove angles and welding conditions from the viewpoint of hot crack occurrence, penetration and shrinkage in the first layer welding, using steel frames welding specimens of straight-line welding joints. In particular, these various experiments showed that though the groove angles and welding conditions were similar, there were differences in hot crack occurrence due to the binding forces.
In this actual study, based on the experimental results in the above, we were able to demonstrate the relationship between groove angles and welding conditions of the first layer in specimens where square steel tubes and diaphragm were joined together. And, we also performed full-layer welding using a 30-degree angle groove. The results were successful and the probability of using welding robots for such columns was confirmed on a 30-degree angle groove.
Shortening the welding time leads to a reduction of greenhouse gas emissions. Therefore, as this is an environmental improvement, we expect this welding process in the steel frames of buildings to become attractive.

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Proper knowledge of exposure severity to wind driven rain and its variation within a wall is indispensable for weather-tight design of external walls. Based on his previous work on estimation of impinging angle of driving rain against wall surfaces, the author has developed a method for calculating rain impingement distribution over an external wall of low-rise residential buildings having eaves overhangs of various shapes and sizes, using hourly records of rainfall and wind for the building site and taking the sheltering effect of the overhangs into account. Recent findings on rain-wetting patterns over a wall of cubic-shaped model building and its variation with wind direction which were obtained through computational fluid dynamics techniques were also introduced in determining the rain deposit distribution in the exposed areas.

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Although the energy transmitting boundary is accurate and efficient for the FEM earthquake response analysis, it could be applied in the frequency domain only. In the previous papers, the author proposed an earthquake response analysis method using the time domain energy transmitting boundary for 2 dimensional problems. In this paper, this technique is expanded for 3 dimensional problems. The inner field is supposed to be a hexahedron shape and the approximate time domain boundary is explained, first. Next, 2 dimensional anti-plane time domain boundary is studied for a part of the approximate 3 dimensional boundary method. Then, accuracy and efficiency of the proposed method are confirmed by some linear and nonlinear problems.

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In this paper, an earthquake response analysis model based on seismic performance indices is proposed to evaluate actual seismic performance of public management apartment buildings appropriately. Damage ratio of buildings are calculated using this proposed model and observed seismic ground motions during the 1995 Hyogo-ken Nanbu Earthquake. As a result, the relationships between an index of seismic ground motion and calculated damage ratio of buildings show good agreement with vulnerability functions based on actual damage data of buildings in the 1995 Hyogo-ken Nanbu Earthquake. Through this study, it is pointed out that damage ratio of buildings could be overestimated, if load carrying capacity which has not been considered in the seismic design is not properly evaluated. Additionally, it is shown that the effect of slit on reinforced concrete wall has a big influence on the damage ratio of buildings.

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This paper shows comparison of earthquake input energy to two types of base-isolated structures. Earthquake input energy for a base-isolated structure incorporated with a magneto-rheological fluid damper using the acceleration reduction control rule is found to be smaller than that of a structure with a viscous damper having the same equivalent damping coefficient. Complex damping is employed to model the magneto-rheological fluid damper and it is shown that the difference of the phase angles of the complex velocity transfer functions for the viscous and complex damped models causes the difference of the earthquake input energy.

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The traditional wooden frame structures of Chinese Dong People have passed through the ages. We investigated the details of the construction system of drum towers, bridges, gates, granaries and drama stages in Dong villages, which are constructed with posts and beams. The beams penetrate the columns and are connected and stiffened without using wedges. In addition, nails and steel connectors are not used. The purpose of the investigation is to make clear the construction system of the traditional wooden structures. We deciphered the allotment of timber written on the surface of bamboo, which were very important for marking, processing and construction of the structures.

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In this paper, wooden frames with knee brace dampers are designed, and their performance is demonstrated. Lateral dynamic loading tests are conducted in order to examine their dynamic properties. Knee brace system can add stiffness and damping to wooden house without closing its opening, which is a great advantage to reduce torsional response of structure. Simplified modeling method for passively controlled frame is also proposed, and it is based on the characteristics of the frame in two states ; without damper and with rigid damper. Dynamic property, maximum response and member's force and deformation can be predicted.

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Existing specimen unconfined compression test of wall clay blended with fibers for plastering has been carried out as rectangular test peace with height 150 mm, width 150 mm and thickness 70 mm. Existing specimens have a shortage that the shear cracking might occurred to the fulcrum or the sprit failure might be easily occurred at failure because of the restriction effect induced the shape of test peace. Authors propose the cohesion and the angle of friction as the strength index of wall clay blended with fibers for plastering. In this paper, the round shape specimen with 2.0 in the ratio of the height to width is proposed based on the soil mechanics. Then, the proposed mechanical model is compared with the results of experiments.

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It is known that the modified Arakawa formula is generally used as the conventional evaluation method of shear capacity in Japan, and it is applied in the case of not only the shear design formula but also the experimental examination. Purpose of this study is to examine the adaptability investigation about ultimate shear capacity of RC columns for compressive strength of concrete ranging from 3.3N/mm² to 116N/mm². As the first report, authors discuss it about consideration based on the modified Arakawa minimum formula using the other researcher's test results data. Take these results, in the present report, the new estimate method taking into account influence of compressive strength of concrete was proposed. In addition, applicability of the new estimate method was validated by comparing the relations of bond capacity.

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This paper presents results of full-scale cyclic loading tests under constant deformation amplitude conducted to evaluate deformation capacity of welded beam-to-column connection adopted in moment frames. Test specimens are designed and fabricated to investigate the influence of flexural strength of beam end connection. The deformation capacity expressed by the relationships between ductility and cumulative plastic deformation is revealed from test results. The relationships between crack growth at welded joint and strength of connection is evaluated regarding deformation amplitude. The initiation of crack is investigated about distribution of stress and strain obtained from FEM analysis.

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In general, the seismic capacity of H-shaped beams with the local bucking is estimated by the two main structural factors. One of them is the plastic deformation capacity in the skeleton curve, and the other is the cumulative hesteresis energy in cumulative hesteresis loops. Their correlation has not been shown even though each one has been individually used as the seismic capacity of the beams. In this paper, the correlation between the cumulative hesteresis energy and the plastic deformation capacity of H-shaped beams are experimentally investigated in 11 test series and the empirical equations based on the previous experimental results are suggested.

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The authors have conceived the buckling-restrained braces (BRBs) providing stable hysteretic behavior under the high-strain conditions. The compressive strength of BRBs generally tends to be higher than the tensile strength. The authors assumed that it was because of friction force between the surface of core plate and the restraining part, and that the magnitude of friction force was related to the buckling mode number resulting in the increase of contact points. A set of prediction formulas for the buckling mode number has been proposed in the authors' previous study. In this paper, the validity of the proposed formulas for the buckling mode number is examined by the test results of strain gauge measurement on the core plate from the cyclic axial-loading tests. Furthermore, the relationship between the strength ratio of the compressive to tensile strength and the slenderness ratio of plastic region of core plate is estimated. As a result, 1) the progress of the buckling mode shape is successfully observed from the test results, and 2) the proposed formulas correspond approximately to the upper and lower bounds of the buckling mode number and also estimate quite well the strength ratio from the test results.

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Firstly, a nonlinear optimization problem is formulated taking only representative dimensions of steel sections as independent design variables. The other dimensions are determined using proportions, prepared from a list of standard profiles, to the design variables. In the optimization, the members are divided into groups having identical sectional dimensions. Then a method is presented for re-grouping of members to further reduce the optimal cost once obtained for a given set of groups. An indicator is proposed to estimate the probable reduction to be brought by splitting a group. Using the indicator, the group and the split that likely bring the most effective reduction are identified. Finally, a flowchart for structural design support system with the above automatic grouping is proposed. This system also contains interactive processes enabling the structural engineer to modify the grouping for a synthetically better design. Examples are shown to verify the validity of the indicator and to demonstrate the advantages of the support system.

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This study aims to evaluate theoretically the fire resistance capacities of concrete filled tubular columns subjected to fire and axial compression. A strength analysis has been made in which all strains found in heated concrete including stress strain, thermal expansion and transient strain are taken into account. Since, among others, transient strain plays a key role on the behavior of heated columns, a new theoretical procedure to treat this strain is postulated and an explicit closed form solution is derived for the ultimate column strength. With comparison between the solutions and test data, it is found that the strength of a heated column is decreased significantly below its full plastic strength due to transient strain, if the column is made of higher strength concrete, is subjected to larger axial force or if it is of a larger cross section. For all the cases, the solutions are found in good agreement with the test results.

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This paper presents a useful numerical calculation method based on the Lanczos and shifted inverse power method in the intermediate eigenpair of sparse and symmetric matrices. The proposed method has a good accuracy and stability in a relatively small computational time. The obtained results agree well with the exact solutions in short CPU time. From these, the present method may be said to provide an efficient approach in the process of the Lanczos and shifted inverse power method

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