This paper deals with the on-site air-permeability of concrete cover and its relation to carbonation progress of existing RC structures in Japan. The air permeability of concretes and carbonation progresses were measured with 4 buildings and 11 concrete specimens which ages ranged from 12 to 45 years. The carbonation velocity (A) based on the square root theory increases with the increase of air permeability coefficient (kT). Although the relationship between A and kT for all building and concrete specimens has quite large scatter, the relationships between them for individual buildings were comparatively good. This might provide a good perspective for indicate that evaluation of carbonation progress based on the kT should be performed at each environmental condition of buildings.

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The purpose of this study is to propose the evaluation method of the contact resistance of the hand targeting handrails from a safety perspective.
First, sensory tests for making scales of operation support were carried out with handrails. Next, the investigation tool that could measure a contact resistance of the hand targeting handrails was developed which was based on the scales and the mechanism of hand. And then, the evaluation indexes which were the relation between a measured value with this investigation tool and those scales were presented.

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Effective modal masses of one-dimensional modes are independent of the manner in which these modes are normalized. However, effective masses of multidimensional modes vary with the rotation of the coordinate system. In this paper, the concept of an effective mass tensor is introduced. It is supposed that effective masses should be recognized as tensors. It is shown that effective mass tensors indicate the inertial masses and principal axes of multidimensional modes, independent of the angle of the coordinate system. An example of a multidimensional structure response under a multidimensional earthquake shows the practical implications of an effective mass tensor.

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This paper addresses the developing of spread foundation surrounded with improved soil which reduces the response of the superstructure. The mechanical properties of the improved compound soil are investigated by laboratory tests. Then earthquake response behaviors of model structures are discussed with various contact conditions at the foundation bottom and different improved backfill soil around foundation by shaking table tests. Furthermore analysis results by 3D-nonlinear FEM are also discussed to clarify the effect of the contact conditions at the foundation bottom and the improved compound soil to seismic response of building.

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Recently, many heuristic methods for topology optimization of structures have been proposed. However, the heuristic method has not been adopted by general-purpose software, because there are several problems in the computational efficiency and the reliability of the solutions. In this paper, a new heuristic method using cellular automaton (CA) and evolutionary structural optimization (ESO) is proposed for implementing to general-purpose software. In this method, the design domain is divided in same FEM elements (cells), and in the optimization process, the elements are deleted by extended ESO method, and the elements are generated by CA method. The performance of the present method is clarified by comparing with SIMP (Solid Isotropic Material with Penalization) method under the same FEM model and the same conditions. Several numerical examples are shown in order to demonstrate the computational efficiency and the reliability of the present method.

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Failure strength of single-bolted joints of wood loaded parallel to the grain was investigated through experiment and analysis. The premature failures represented by end transverse tensile fracture and push-out shear fracture, which must be avoided in construction practice, took place when the end margin is small. For the end margin not less than four times the bolt diameter, the strength kept constant in favor of bearing yield of wood in advance of splitting, in that the embedment up to the fracture increased with the end margin. Formulae for calculating the embedding strength and the premature failure strengths were proposed in consideration of orthotropic strengths of wood and frictional coefficient between bolt and wood hole. The experimental results demonstrated that the formulae give satisfactory predictions corresponding to the failure modes.

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Experiments were conducted to study shear strength of wall located above an open frame. Based on the observed failure modes, a rigid-plasticity model was proposed. The shear strengths computed using the proposed model agreed with the observed ones. The vertical reinforcement in the wall panel, as well as the flexural and shear strengths of the boundary beam, greatly affected the shear strength of the wall.

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This paper summarizes experimental results of 13 shear wall specimens with different structural details of confined area at wall end. Experimental results revealed that flexural deformation capacity of the specimens increased with existence of boundary column, expansion of confined area, application of hoops, etc. Moreover, structural parameters of confined area related to flexural deformation capacity were investigated to propose some key parameters for designing shear walls that fail in bending with concrete crushing. Axial/shear stress of confined area was found to be closely related to flexural deformation capacity of shear walls.

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The ultimate state of beams subjected to plastic cyclic loading shows complicated behaviors because plastic deformation and local buckling are combined. In order to clarify the ultimate behaviors, enormous experimental studies have been conducted. And also, the prediction methods of ductility and damage evaluations of beams have been proposed. In this paper, the ductility of steel beams subjected to plastic cyclic loadings are reviewed with a large number of past references, form which a database is structures. Furthermore, the effects of size of section and cyclic loading history are investigated. And the damage evaluation methods considering these parameters are proposed.

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The authors conceived a buckling-restrained braces (BRBs) providing stable hysteretic characteristic even under high-strain conditions. In the past paper, conducting cyclically static loading tests, the performance evaluation formula of the buckling-restrained braces was presented. By making core plate form of BRBs into a cruciform, the width direction of that can be made smaller than that of flat steel. In this way, when BRBs with cruciform applies to buildings, it becomes easier to secure openings. However, welding is necessary for assembling of core plate on this occasion. When the welding exists, the performance of the BRBs would be decreased. It is necessary to reveal that the problem of strength matching of fluxes which formed welding. In this paper, the specimens with different welding specifications on the core plate of the energy absorption area are fabricated. As a result, 1) the effective cross section of the intermittent fillet welding on core plate is larger, the performance of the specimens is better, and 2) by using welding wires with the even strength of the base metal, BRBs have the even performance of the base metal.

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Buckling restrained braces (BRBs) are widely used in seismic regions as ductile seismic-resistant and energy dissipating structural members. One of the key limits of BRBs is overall flexural buckling, and they are required to exhibit stable hysteresis under cyclic axial loading with initial out-of-plane drifts simulating the bi-directional effects of a ground motion. However, many researches are indicating that there are risks of overall buckling caused by connection failure, before the BRB core yields. In this paper, the stability conditions of BRBs including their various connection conditions and initial out-of-plane drift are discussed and a unified simple equation set for securing the BRB stability is proposed. Moreover a series of cyclic loading tests with initial out-of-plane drifts is carried out, and results are compared with the proposed index.

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In order to clarify the seismic resistance of steel moment frames, it is necessary to establish an analytical model of RHS columns that can simulate the members' behaviors including post local buckling and deterioration under bi-directional horizontal forces and axial force. In this study, a multi spring (MS) model which consists of elastic and inelastic elements was employed in the analysis. The hysteretic model of the axial springs which compose the inelastic element was established based on the hysteretic model of RHS columns under uniaxial bending. In addition, a series of cyclic loading tests of RHS columns under random bi-directional horizontal forces and constant axial force were conducted to calibrate the proposed analytical model. The simulated RHS column behaviors, including post local buckling and deterioration, agreed with the experimental results.

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For the demand to improve the safety and livability of the high-rise building, the wall-type viscoelastic damper has been come into practical use. For applying to high-rise RC structure, it is conceivable to use the connection system encased by RC bases. An experimental study is carried out to obtain the design data of this connection system for performance evaluation. Sundry strength is investigated and it is shown at the conclusion, the allowable strength should be less than the strength calculated from allowable stud strength, or the value obtained by dividing the safety factor of the ultimate strength after cracking.

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The Rockwell hardness of high-strength bolt sets subjected to high temperature was measured. According to these data, the equation that Rockwell hardness decreased at 7HRC per 100℃ above the tempering temperature was proposed as a conservative simple estimation method for fire-damaged investigation. The temperature of high-strength bolt sets was decided by averaging three temperatures, which estimated by applying the proposed equation to bolt, nut and washer. The proposed method was applied to the fire resistance test on full-scale beam and the measured temperatures of bolt sets could be estimated with adequate accuracy.

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A design formula for estimating tsunami loading on buildings for vertical evacuation from tsunamis is proposed in this paper. Instead of the hydrostatic formula recommended in the temporary design guideline notified by the Ministry of Land, Infrastructure, Transport and Tourism, the hydrodynamic formula based on the Morison equation is employed to take into account the dependency of fluid forces on flow velocity. Using the relationship between the fluid velocity and the inundation depth derived under the hypothesis of the boundedness of the momentum flux and the Floude number, the formula for tsunami wave force is presented in terms of the design inundation depth, which is usually available in the tsunami hazard map. The validity of the proposed formula is confirmed by estimating tsunami wave forces on the buildings attacked by the 2004 Indian Ocean Tsunami and the 2011 Tohoku Earthquake Tsunami.

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