Shrinkage reducing agent (SRA) is one of chemical admixtures for concrete during mixing, which was developed to reduce drying shrinkage in concrete due to low surface tension. The frost resistance of mortar incorporating the traditional type SRA could be reduced. Therefore, the modified type SRA was developed to improve the frost resistance. In this study, shrinkage properties, frost resistance, pore structure and characteristics of pore solution in the mortar using the traditional and modified types SRA were discussed. It was suggested that the characteristics of pore solution in addition to the pore structure affected the shrinkage properties and frost resistance.

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Next generation waterproofing specifications were discussed in the paper. Much amount of greenhouse gas emission and much cost during service life of 100 years were pointed out through the LCCO₂ and LCC calculations of waterproofing membranes renovated by the present specifications. For reducing them, two types of specifications for future waterproofing system, such as an envelope type specification of requiring very few times renovation and a built-in type specification of not requiring renovation, were proposed. The calculated results for the proposed specifications by the new concept show much amount of reduction in LCCO₂ and LCC.

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Air permeability of structural concrete is one of the properties of concrete in the surface layer concrete. It is strongly relative with the rate of carbonation. For this reason, air permeability test is effective with respect to the evaluation for the durability of structural concrete. Having intended to measure air permeability of structural concrete in site, the authors have handled rapid air permeability test which is based on J. W. Figg's concept. This paper proposes "rapid test method for air permeability of structural concrete with drilled-hole" which is considered to apply for structural concrete. The method is also specified according to the knowledge of examination for the factor on air permeability. The paper moreover presents the tendency which test results indicate on each factor of affecting the rapid air permeability test.

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It is very important in numerical computation to know the time of change in velocity direction as accurately as possible, when vibration systems with sliding friction are analyzed by using numerical computations. Takahashi et al., (2012) introduced a new analytical logic that could estimate the time changing the velocity direction within the constant time step (Δt) by using the Linear Accelerated Method. Here, on the basis of linear single-mass systems with sliding friction and without external force, the accuracy of estimated time is evaluated by comparing with the theoretically obtained time that gives the change of velocity direction. The absolute differences between the estimated time and the theoretical one depend upon the size of time step Δt. It can be shown that the absolute difference for Δt=0.01 sec is smaller than 0.0001 sec. This fact means that the computing accuracy obtained by the new logic using Δt=0.01 sec is almost equal to the one obtained by other logic using Δt=0.0001 sec.

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This paper investigates the influence of earthquake locations and an accretionary wedge in the Nankai Trough area on long-period ground motions in Tokyo using the 3D finite difference method. There is not much difference in ground motions in Tokyo when earthquake sources in the Japan Trench and the Nankai Trough are hypothetically assumed to be in the same conditions (e.g. moment, depth). Considering accretionary wedge in the Nankai Trough area, response is larger above accretionary wedge and smaller in Tokyo. It's suggested that the accretionary wedge is easy to trap seismic waves and doesn't necessarily enlarge response in distant Tokyo.

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Three noticeable cases of damage during the 1995 Hyogoken-Nanbu earthquake are reviewed; the damage rate of reinforced concrete buildings in Kobe city, the behavior of the Shin-Nagata high-rise residential building, the fractures of columns of high-rise buildings in Ashiyahama Seaside town. In these cases, the predominant periods of ground motions are considerably longer than the natural periods of buildings and resonance is not expected. These phenomena are examined by a proposed response spectrum of elasto-plastic system with constant damping factor and explained as transitions of natural periods of buildings. This method gives appropriate estimates of an increase in period with an increase in amplitude.

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By using high-performance seismic sensors, dynamic characteristics of a base-isolated high-rise building and its change during construction are discussed. A series of ambient vibration data, several seismic response records and manpowered forced vibration data were obtained at the building in approximately one year of construction. Observed response characteristics, estimated natural periods, damping ratios and mode-shape are shown with the change of building height under the same isolator, soil and foundation condition. Difference of dynamic characteristics between seismic response and micro-tremor, and soil-structure-interaction effect are also discussed.

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This paper presents damage and structural performance of lead rubber bearings which experienced shaking table tests on seismic isolation systems. During the shaking table tests, some of the bearings ruptured due to excessive shear deformation. After the tests, failure surfaces were observed to confirm that these failures started at not bond layers but rubber sheets. Static loading tests were conducted on bearings without rupturing to evaluate structural performance before and after the shaking table tests. Then these bearings were cut in the main loading direction to observe inner damage. In addition, test pieces were made from these bearings to perform shear material tests and peeling tests. It was found that, although inner damages of the rubber and steel were observed around lead plugs, fundamental performance of the bearings was less deteriorated even after the shake table tests.

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A new and effective yield criterion and strain hardening rule for orthotropic materials such as wood are presented. The specific stresses, the ratios of stresses to the corresponding yield stress and called as the non-dimensional stresses in this study, are introduced in the principal axes of anisotropy, and the present yield criteria is expressed as quadratic form of the specific stresses. Also, the strain hardening rule, in which the strain hardening characteristics are established individually for each principle axis of anisotropy, is shown. In order to verify the applicability of the present constitutive law for the wooden material, several numerical experiments are performed and show that the present approach has the promising potentiality to trace and evaluate the wooden specific characteristics qualitatively.

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The forced vibration tests and the simulation analyses were performed for a large-scale RC building model constructed on the actual ground. The following findings were obtained for the embedded effects; 1) the displacement amplitude on the roof level of the embedded building model becomes less than half of that of the unembedded building model; 2) the response don't change so much, even when the width of MMR, a backfill material surrounding the model, is reduced from twice to 2/3 for the foundation width of the building model; 3) the responses characters obtained by the tests can be simulated well by the analyses in which the thin-layer element method and the 3-D FEM are combined for the surrounding soil.

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The bending moment of the beam is varied along the member under the dead load and lateral seismic load, and then the stress of the upper flange with the lateral bracings become compressive or tensile. Therefore the lateral bracings connected to flange need to have the lateral and rotational rigidity to prevent the lateral buckling of the beams when the upper flanges have the tensile stress. In this paper, the elastic lateral buckling load of H-shaped beams under moment gradient is developed with the energy method, and the relation between the elastic lateral buckling load and the required rigidity is clarified. Next, the elasto-plastic lateral buckling moment is evaluated using the modified slenderness ratio with the elastic lateral buckling load.

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In this paper, the complex nonlinear buckling behaviors of pressurized latticed cylindrical shell roofs affected by geometrical initial imperfections have been investigated. The sectional area of roof members of the adopted latticed cylindrical shell has been designed by dead load. Then the nonlinear numerical experiments for various imperfection amplitudes and modes have been analyzed. Also a simply calculated buckling loads based upon the continuum shell analogy has been represented. This simple design procedure would be useful for the design of linear buckling loads for single layer cylindrical latticed roofs.

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Liquid-filled tanks on a shaking table showed vibratory responses that contradicted the predictions of elementary vibration theory. The author has been studying the responses that might be caused by the dynamic geometric nonlinear behavior of the system and showed the Lagrangian function that governs the interactive behavior between a potential fluid and elastic container for large deformations. Arbitrary Lagrangian-Eulerian Elements (ALE) were applied to the functional of the two-dimensional model, proposed a new procedure to analyze the problem, and obtained various nonlinear vibration responses orresponding to the vibratory responses in experiments using a shaking table.

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Application of energy dissipation devices for the seismic retrofit of truss towers has been recently researched, because these structures have been generally designed against wind load, and are possibly to be damaged by large earthquake. Although the effect of energy dissipation devices has been confirmed, the arrangement methodology of these devices has not been established yet. In this study, optimization techniques are applied to arrangements of devices. Firstly, a response evaluation method using response spectrum and equivalent linearization method is proposed. Second, the proposed method is applied to the investigation of optimum arrangement of visco-elastic damper devices on a telecommunication tower. Additionally, the device arrangements by the conventional design methods are compared with the optimum solutions. The results demonstrate that the conventional design is significantly effective to determine the optimum device arrangement.

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The objectives of this study are to analyze the dynamic behavior and to evaluate the maximum response of two-storied traditional wooden buildings against pulse-like ground motions. It was found from shaking table test and simulation analyses of two-storied wooden frames that structural properties cause the interactive effects between the first and second story, asymmetric restoring force characteristic, and uplift motion of column base. Based on the experiment, we suggest the simplified evaluation method of maximum deformation which is evaluated from equivalent natural period of building, period and displacement of input pulse wave using response spectrum.

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The shape of commercial dovetail joints, which is machined with precut system, is not suitable for machining. This form has the disadvantage that cannot be machined in a single pass. In this paper, we proposed a variant of the weaknesses of its shape. Conducted shear tests and tensile test, we discussed the relationship between the shape and the strength properties . In addition, we compared the performance of the experimental values with the calculated value by the current design equations.

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This paper discusses a strength evaluation method of precast multi-story shear wall system which allows slip failure of the vertical joint between wall panels and boundary columns. Shear force of the vertical joint is transmitted by cotters and the joint reinforcements of beam position. Ultimate strength of the wall system is evaluated by adding strength of a wall panel by the calculation method shown in our previous paper and shear forces of the columns. The results of this method were compared with loading tests of the precast wall systems. The calculated values were in good agreement with the experiments.

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Spheroidal graphite cast iron is not allowed to use the structural members in buildings, because its ductility is considered to be very low. On the other hand, this iron is often used to automobile parts. This study investigates the ductility of this iron, and clarifies the possibility to apply to the structural members in the structures. This paper clarified the tensile performance of the spheroidal graphite cast iron material and the performance of the tension and compression member with a casting surface. It is shown that spheroidal graphite cast iron pipe members under compression load have the brittle behavior after post local buckling.

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This study proposes a formulation for applying Bayesian updating for safety inspection of steel frames suffered from strong ground motion in which beam-to-column connections are potentially fractured. In the proposed method, probability distributions of deformation demand and capacity of connections are modeled as that their variations are divided into those of the average error as whole building, and those of deviations from the average. Then, Bayesian updating is applied for the former alone. In order to use for the proposal method, the variations in demand and capacity of connections are examined. For demand, MCS (Monte Carlo simulation) for time history analysis shows that the variation of the maximum rotation at beam-to-column connections is estimated to be 12 to 14% s logarithm standard deviation. For capacity, about 20 % as logarithm standard deviation is statistically estimated from past structural tests for cumulative plastic deformation ratio. Finally, an MCS for a 9-story plan frame is presented as an illustrative example to examine the accuracy of the proposed method.

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In the field of building construction, mass consumption of wood materials contributes to reforestation as well as to reduce environmental burden. At present, a composite steel-timber structure has been used in several building structures and is expected to be used even more widely in the future. The authors proposed the composite steel-timber structure which system is based on a damage-controlled structure. This structural member is composed of steel and glued laminated timber. In this paper, a design method of the composite steel-timber structure using buckling-restrained knee braces is proposed on the previous experimental tests. A trial design is conducted where applicability of the design method is shown.

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Viscous-type dampers used for buildings can reduce building vibrations ranging from minor shaking by traffic loads to major shaking by strong earthquakes. In order to increase their efficiency, deformations of integrating component adherent to the viscous damping component must be minimized so that most deformation takes place in the latter, maximizing dissipation of the kinetic energy. Both theoretical and approximate solutions are proposed for estimating the efficiency of a brace damper, by considering axial deformations of the integrating components. They are based on the differential equations of the axial strains in complex domain, expressing strain and stress in- or out-of-phase with the stroke imposed to the damper. For time-history analysis, a simplified modeling method for the interaction between the two components is proposed and its accuracy demonstrated.

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