Medium volume blast furnace slag concrete has been highly expected to contribute to reducing carbon dioxide emission in concrete production. However, it was found that this concrete appears to be prone to shrinkage cracking specifically under hot summer climate. To improve this negative performance, this study focused to utilize morsel additives and water curing. The morsel additives are gypsum and calcium carbonate, with which binder is called low shrinkage BFS. Furthermore, to reduce prominent autogenous shrinkage, initial water curing is to be investigated. As a result, combining low shrinkage BFS and water curing was found to significantly strengthen shrinkage cracking resistance, which was expressed by cracking age resulted in restrained shrinkage cracking tests. Furthermore, curing experiment showed that water curing may be substituted by water covered curing on element surface in construction site as a simple and economical measure to supply water to concrete at initial stage of hardening.

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 This research work focuses on an index to the extent of the carbonation progress of ALC based on the carbonation-saturated condition. The progress of carbonation can serve as an index to changes in the strength of ALC panels over time. However, the proportion of calcium carbonate (CaCO₃) to the total calcium content in ALC at the time of saturation of carbonation reaction varies depending on its production history. Therefore, relative comparison between the degrees of carbonation of different types of ALC is unfeasible solely by comparison of the quantity of CaCO₃ generated by carbonation. In contrast, the level of progress up to saturated carbonation in terms of CO₂ can be used as a parameter for relative comparison. The authors therefore propose the use of the level of carbonation progress for estimating the strength loss. It was also found in this study that the strength of ALC subjected to carbonation in an accelerated environment is retained equal to the initial value up to a level of carbonation progress of around 50% but decreases to 70% with a level of carbonation progress of 100%.

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 Powder coating on aluminum alloy materials has not been popularized yet in Japan's construction industry field. Therefore, experimental evaluation for powder coating system with chromium-free chemical conversion has been continued in order to establish aluminum alloy surface coating system that takes into consideration environmental prevention. In this paper, experimental evaluations for the combination of several kinds of powder coating and some kinds of chromium-free chemical conversion are discussed.

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 Large Eddy Simulation (LES) is expected to be adopted as an effective technique to evaluate wind load on buildings for wind-resistant design. For numerical prediction of wind pressures by LES, unstructured grid system is effective in terms of flexibility in generating computed models. In this paper, the fluctuating wind pressures on a high-rise building in a real urban district are examined using unstructured LES. Especially, focusing on the pressure distributions influenced by surrounding buildings, the method of model generation for accurate prediction is shown and the flow fields are studied to elucidate the mechanism of peak pressure occurrence.

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 Because shaking modes of super high-rise buildings are very complicated, it is not enough to perform health-monitoring only for the whole structures. We try to extract story-by-story shear-wave velocities applying the deconvolution method to microtremor records measured at super high-rise buildings. The shear-wave propagation (including reflection, transmission, and interferometry at the boundary of stories) extracted from microtremor records are compared with those simulated ones using 2-D frame models with different mass-and-rigidity distributions which lead to different shaking modes. Story-by-story shear-wave velocities can be extracted from buildings whose shaking modes of all the stories are mainly shear modes. However, the shear-wave velocities of the buildings cannot be extracted successfully, if the stories are shaking in pure bending mode, because no inter-story shear deformation happened, the apparent shear-rigidities of these stories can be seen as infinite, which lead shear-wave travel times to zero.

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 This paper describes the passive control method of mid-story isolation buildings designed to mitigate seismic response in the substructure. An equivalent two degree of freedom system consisting of both the substructure and the super structure is introduced. Optimal parameters of the isolation are formulated for the building subjected to white noise ground motions. The equivalent frequency and the damping factor of the equivalent single degree of freedom (SDOF) system are defined based on the random vibration theory. The practical estimation methods of maximum responses are proposed with the combination of the SDOF model and the response spectrum method. Finally, performance curve diagrams are presented.

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 This paper derives equations to predict hysteresis energy of SDOF systems for a wide range of damping ratio. In order to confirm the effectiveness of the proposed equations, time domain analyses under recorded earthquakes are conducted for a lot of SDOF systems with various yield strengths and damping ratios. Concluding remarks are as follows.
 1. For 2 % damping ratio, not only the proposed equations but also almost previous equations show good corresponding to time domain analyses.
 2. For 5% or 15% damping ratio, the proposed equations show good corresponding to time domain analyses while almost previous equations overestimate hysteresis energy.

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 Improperly secured furniture, especially on the upper floors of high-rise buildings under long-period ground motion, can become dangerous objects for human life. Many tumbled furniture such as chairs and desks in schools could become fatal obstacles that obstruct children from evacuating. In this research, an effective numerical code to analyze the motion behaviors of furniture subjected to seismic excitations was developed. The numerical code was developed based upon the adaptively shifted integration (ASI) － Gauss technique, which is a finite element scheme that provides higher computational efficiency than the conventional code. The frictional contact between objects was fully considered by employing a sophisticated penalty method. Some excitation tests of furniture on a shake-table were carried out, where steel cabinets were excited by seismic waves and the displacement data were recorded by a motion capture system. The numerical results were validated by comparing with the shake-table test results.

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 This paper reports on a method for estimating the behavior of a tie-rod anchored retaining wall. The displacement of stay piles and retaining wall was measured to evaluate wall behavior. Measurement results are used to show that the displacement control effect of a retaining wall is small if separation distance is short, and consider a method for estimating backside ground horizontal displacement under the influence of wall displacement. A behavior analysis model using Winklerian model considering the effect of backside ground horizontal displacement is proposed, and fair agreement between calculated and measured values is shown.

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 The present paper discusses on ultimate strength of single layer reticular domes under dead and seismic loads and proposes a method to evaluate seismic performance which can be applied to for structural design. The domes are supported by pins at its circular periphery. The safety factor for dead load is set up for an analysis parameter. First, classical buckling load under the dead and seismic loads is newly derived mathematically based on a simple approximation, followed by comparison with the linear buckling load calculated using FEM analysis. Second, elastic buckling loads considering geometrical imperfections are calculated. Imperfection sensitivity is discussed, and a formula is proposed to evaluate elastic buckling loads based on the formula. Third, elastic plastic buckling loads considering geometrical imperfections are calculated. Then, the results are compared with and those evaluated using an approximate equation of Modified Dunlerley's equation. Finally, the dynamic ductility indexes based on the previous study of the domes are calculated, and an efficient scheme is proposed to evaluate of the seismic performance of the domes from a point of practical application.

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 In Japan, the stress transmission of RC beam-column joints is calculated differently depending on their type of joint. In interior joints, main bars are continued through the joint panel both vertically and horizontally. However, main bars in knee joints are not continued in general. Additionally, since there is slight vertical load on knee joints from above, sufficient bond between concrete and main bars cannot be expected and that makes the joint panel relatively easy to break under stress transmission. In the previous studies (Hotta and Nishizawa 2012), it was concluded that the sufficient inside radius of the main tensile bars continuously arranged through the panel from beam to column improved bearing strength between curved bars and concrete, and also improved shear strength of the panel as a result in the joint panel subjected to closing force. The objective of this following study is to show the influence of the inside radius of the main tensile bars which are separately arranged in the joint panel in line with a practical design under stress transmission by conducting closing and opening load.

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 Firstly restoring force vs. story drift models for columns with sidewalls are proposed paying special attention to the difference of damage level of sidewalls and columns. Secondly inelastic earthquake response analyses using multi-spring story shear models are conducted. Three analysis cases are considered, i.e. failure mode of contribution of column is fixed to flexure, failure mode of contribution of column is calculated and sidewalls were eliminated imaginarily. Main conclusions are as follows: (1)Measured residual seismic performance ratios are roughly evaluated. Especially the difference of measured ratios concerning the members are evaluated. (2)The existence of sidewalls is supposed to be effective to prevent North Building from pancake type collapse damage.

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 Steel frames retain residual deformation after a huge earthquake, their continued use is impractical. This paper aims to decrease residual deformation by use of connections incorporating a wedge device. A loading test on a specimen with a beam joint connected by conventional bolts and using such a device shows that its restoring force characteristics are of the linear-from-origin type. Seismic response analyses of steel frames with such wedge device connections lead to the following conclusions: they show no residual deformation; and story deformation angles, story shear forces, story shear coefficients, and energy absorption capability are equivalent to those for rigid frames. Furthermore, plastic deformation behavior of the wedge device connection is superior to that of rigid frames.

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 The objective of this study is to clarify the relations between the effective length and bracing stiffness of braced compression members subjected to linear varying axial force. Bracings are composed of from one to ten discrete bracings at the equal intervals or continuous bracing. The buckling equations are derived by using the Rayleigh-Ritz method, and the effective lengths of columns are calculated, taking the bracing stiffness ratio and axial load ratio as analytical parameters. After discussing the relations between the effective length and bracing stiffness, relations between discrete bracing and continuous one, the required stiffness to ensure some given effective lengths are presented.

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 This paper presents plastic deformation capacity determined by fracture or local buckling of the cold press-formed SHS columns by the cyclic loading test and finite element analysis with varying width-thickness ratio, shear span ratio, loading direction and ratio of axial force to axial yield strength. As a result, it is pointed out that the crack at the end of column occurs when width-thickness ratio and shear span ratio are small. And also it is notable that the possibility range of parameters with initiation of the crack is spread if loading direction is 45 degree.

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 This paper presents results of full－scale cyclic loading tests of moment connection conducted to evaluate deformation capacity. Deformation capacity of flange－welded web－bolted beam－to－column connection is investigated by three types of cyclic loadings, i.e. constant amplitude, two different constant amplitudes and random amplitudes. Deformation capacity of moment connections with weld access hole under varying amplitude cyclic loadings is estimated by proposed method which is obtained using crack propagation.

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 The objective of this study is to examine the strength formulas of square steel tubular beam-columns on the basis of the strength formulas specified by the “Recommendation for Limit State Design of Steel Structures”. The strengths of square steel tubular beam-columns are obtained by the analytical work, where the axial load ratio, slenderness ratio and moment gradient ratio are selected as a numeric parameter. The stress-strain relation is assumed to be elastic-perfectly plastic. Relations between analytical maximum strengths and the strengths calculated by using the AIJ LSD guide are presented and the validity of the strength formulas is investigated.

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 This study presents the results of a three-point bending test performed on a cold-formed square hollow section (SHS) column to a through diaphragm welding connection using a 25 degree narrow groove. The test results are summarized as follows:
 The deformation capacity of a cold-formed SHS column to a through diaphragm welding connection by using a 25 degree narrow groove is comparable to or higher than that obtained in previous tests by using a 35 degree standard groove. Relieving the stress concentration at the weld toe through grinder finishing delayed ductile crack initiation, thus improving the deformation capability of the welded connection of the cold-formed SHS column.

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 In this paper, the cyclic behavior of concrete filled steel tubes (CFTs) using high strength (HS) steel “H-SA700” under combined constant axial and flexural loads was investigated experimentally. In the CFTs made from HS steel, the compressive strength of concrete was reached before steel yielding. Thus, a design method which takes into account this phenomenon for estimating the yield strength capacity of HS steel CFTs was proposed. Good agreement was observed between the test and estimated values. In addition, after ultimate strength reached the inelastic behavior of HS steel CFTs was similar to that of conventional ones.

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 Thermal deformation of structural members during fire may become the factor to cause the collapse of the building. Above all, thermal elongation of steel beams is one of the most significant considerations for the structural stability of steel buildings. In this study, four types of full scale furnace tests were carried out to grasp the thermal elongation of steel beams which were connected to RC slabs. All specimens were composed of fire-protected steel beams and RC slabs whose three sides were completely constrained. Test parameters were the cross-sectional size of beam and grade of fire protection. By comparing test results, the suppressive effect of the typical RC slab to the thermal elongation of steel beams were quantified. It was found that the thermal elongation of steel beams which were connected to the RC slab were around 80% of the value that is provided in Eurocode 4 regardless of test parameters.

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 Generally, in the case of designing seismically isolated structure, tensile design limit value for laminated rubber bearing is defined by tensile stress. The critical value is defined as 1 MPa independent of type of rubber bearing. However, in case seismically isolated structure is designed using design limit tensile stress value, tensile stress often transcends 1 MPa. If tensile stress transcends design limit tensile stress, special device which can avoid generation of tensile deformation is used. This becomes an obstacle to designing seismically isolated structure. In order to alleviate this obstacle, the method which tensile design limit value is defined by tensile strain is proposed in this paper. First, outline of tensile test condition to define design limit value of tensile strain and its test result are shown. Next, design limit value of tensile strain and tensile modulus is proposed. Finally, prediction accuracy by FEM analysis for tensile deformation of laminated rubber bearing is verified.

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 To investigate the applicability of slurry infiltrated fiber concrete (SIFCON) for use in blast-resistant structures, experimental investigations were conducted to evaluate the spall-reducing performance of SIFCON slabs subjected to contact detonation. The test results showed that SIFCON was more effective in reducing spall damage due to contact detonation as compared with normal concrete and other various fiber reinforced cementitious composites. Furthermore, the spall and perforation limits of SIFCON slabs subjected to contact detonation were identified based on the test results.

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 In this paper, the authors have proposed a method to determine the necessary number of the braces for the ceiling area from the specified displacement criterion. When the ceiling can be regarded as a linear single degree of freedom system, the fundamental period of the ceiling is the design parameter to control the maximum displacement for the given design response spectrum, and the target fundamental period can be determined for the specified displacement criterion. When the ceiling is regarded as a nonlinear system, the necessary number of the braces can be estimated based on the relationship between the supporting area for a set of the brace and the maximum earthquake displacement of the ceiling. The supporting area for a set of the specified brace can be determined by the story number of the building, the floor number of the ceiling and the displacement criterion. The validity of the proposed method is verified by the time-history analysis by using the observed seismic records of the 2011 Tohoku Pacific Earthquake.

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