The spreading awareness of green issues in recent years has prompted us to develop environmentally friendly concrete: ultra high strength concrete that contains high volume of by-products. Compressive strength tests were conducted using mortar and concrete specimens containing various by-products. As a result, we suggested a computation approach of the compressive strength of mortar by using a regression expression that uses the chemical composition and the mixing condition of the by-product as parameters. And CO₂ emissions from the component materials of this environmentally friendly, ultra high strength concrete reduce 40% of the emissions for conventional ultra high strength concrete.

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This paper reports the results of long-term outdoor exposure test on the rate of corrosion of reinforcing bar in concrete which contains chloride ion. The factor of experiment are sodium chloride content (0-1.0%/sand), water-cement ratio (50-65%), and thickness of concrete cover (15-40mm).It is concluded as follows, The corrosion loss of reinforcing bar in long-term outdoor exposure test increases in proportion to square root of exposure period. Rate of corrosion of reinforcing bar decreases with increasing thickness of concrete cover in sodium chloride content(0-0.3%/sand). The estimation equation of the rate of corrosion of sodium chloride content(0-1.0%/sand) are proposed by thickness of concrete cover and water-cement ratio.

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In this paper, total strain and time dependent change of thermal expansion coefficient (TEC) under temperature history of cement paste with W/C=0.3,0.4,0.55 whose binder is normal Portland cement, moderate Portland cement and low heat Portland cement were investigated. In all conditions, a rapid reduction of TEC was observed in very early age and TEC showed the local minimum value around 12-18hour. After that, it gradually increased with reduction of moisture content. During that term, low heat cement could reduce this increment of TEC under high temperature history. This time dependent change of TEC could produce shrinkage as thermal strain with temperature dropping. The amount of this thermal strain is relatively large, and in the case of W/C = 0.4, low heat cement shows lower thermal strain.

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In this study, experimental investigations were conducted regarding the following three items: 1) effect of clad reinforcement of carbon fiber reinforced mortar (CFRM) on flexural performance of reinforced concrete (RC) beams; 2) electromagnetic shielding effect of the CFRM; and 3) the state of electrolytic corrosion of rebars placed in the CFRM after long-term (15 years) exposure. Our results showed that the CFRM was effective in improving both flexural and electromagnetic shielding performances of RC members, without accelerating electrolytic corrosion of rebars placed in the CFRM. However, more investigations are needed to evaluate electromagnetic shielding effect of CFRM in full-scale RC members and electrolytic corrosion of rebars under more long-term exposure.

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Recently, demand on the global environmental management and human health and safety is getting big worldwide social problem. Harmful substances influence on human health and safety. In Japanese construction industry fields, chemical conversion with chromium VI reagent in surface preparation process and solvent type paint in coating process have been applied to surface finishing on aluminum alloy building materials. Against the backgrounds, Japan Society for Finishing Technology has been studying these themes since 2006. In this paper, experimental evaluation measures for the surface preparation are discussed on experimental results.

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This paper re-proposes a synthetic method of estimation of safety, reparability and serviceability for buildings from a viewpoint of seismic risk based on author etc (2010). The seismic risk curves regarding death rate, loss and building downtime are assumed to show safety, reparability, and serviceability in seismic performance. The effects of the interrelationship between the earthquake motion and the building response characteristics on each seismic risk were analyzed in detail. The results showed that, because the contribution of the structural frame, nonstructural elements, and building equipments to seismic risk was greatly affected by the interrelationship, there was a trade off relationship among the abovementioned seismic risks that depends on the evaluation conditions. This suggests the usefulness of determining seismic performance based on multifaceted seismic risk assessment.

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This paper presents a procedure named ductility factor control method for moment-resisting frames with tuned dynamic mass systems. The objective is to estimate yield moments and other parameters satisfying target performances such as ductility factors for structural elements and viscous damping ratios for its system. This is a new version of the original paper presented by Ishimaru in 1975, which consists of a pseudo modal analysis making use of the combination between time history waves of nonlinear SDOF systems as modal coordinates and their participation vectors regarding to structural elements. The numerical examples show that the method is able to facilitate its implementation in practical design with high accuracy.

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The objective of this study is to establish a method of evaluating the maximum response of traditional wooden buildings during strong ground motions by microtremor measurements which is used to evaluate their natural frequency. To clarify the relationship between the maximum response and the vibration characteristics, the shaking table test of wooden frame structure is conducted. Using response spectra method, the maximum response considering the damage by former earthquakes is evaluated from the expression of the amplitude dependency of the vibration characteristics. We confirm this method can evaluate the maximum response approximately.

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Human power exciting force was measured for four persons. The target excitations were sinusoidal sweep waveforms from 0.15Hz to 2.0Hz and from 2.0Hz to 0.15Hz. The maximum adaptable frequencies of the excitations were different from person to person. The overturning moment of each person was almost constant for the adaptable frequencies. Based on the test results, an evaluation formula of human force was proposed. The human power vibration tests carried out previously on actual buildings were also presented. The formula was verified and modified regarding the test results.

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Wind load is the most dominant load for light-weight structures such as membrane roofs. Particularly since the horn-shaped (conic) membrane roof has a complicated shape, the basic data for the design wind load on the horn-shaped membrane roof has not been reported.
In this paper, the authors focus on the wind-load on one-unit horn-shaped membrane roof with rise-span ratio of 0.2, and report wind tunnel tests for it. From these tests, the wind pressure coefficient, fluctuating wind pressure coefficient and peak wind pressure coefficient are provided under the natural wind of terrain III. In addition, the comparison between static response analyses and dynamic response analyses using the result of wind tunnel test indicates the gust factor based on stress of the membrane.

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The purpose of this study is to develop the new seismic strengthening method of existing wooden houses. In this study, the fiber reinforced plastics (FRP) are used as the reinforcement material. This FRP hardens by irradiating the ultraviolet ray. In this study, we develop a good workability seismic strengthening method for existing wooden houses by using this FRP sheet. As a result, we were able to develop the new reinforcement design for the braced frame structural wall of the element ultimate strength (the wall ultimate strength factor) as over 4.0(kN/m) which was target value in this study.

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A horizontal framing in a timber structure must keep a vertical load, but also have in-plane stiffness and strength in order to let a horizontal resistance element such as the bearing wall works effectively. In this study, it's intended that we grasp and evaluate the shear property of a thick structural plywood floor with/without floor opening. The thick plywood is used without joist for floor that is effective for the security of stiffness and strength. At first we carried out shear experiments on floor with/without floor opening, and grasped a shear property of them. In addition, we executed tension and bending test of beam-beam joint, shear test of plywood nail, shear test of structural plywood unit wall and grasped a property of those mechanical properties. Furthermore, we suggested evaluation method for shear stiffness and strength of floor with/without floor opening and showed the validity of it.

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In this paper, we present a study on behaviors of a collapsed timber structure under heavy snow load. On our disaster investigation, a feature was found that the span directional frames collapsed toward out-of longitudinal plane. We showed a simplified mechanical model to consider stress transfer in the joint between tie beam and column. The equilibrium path analyses of the timber structure revealed the existence of unstable bifurcation buckling. The buckling modes were torsional deformation and sway in span direction. In conclusion, the primary factor to the collapse is flexural and torsional buckling in the overall structure.

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Most formulae to calculate the shear stiffness of a sheathed shear wall are derived with the assumption of rigid frames connected with pins. But the flexural stiffness of vertical studs affects the shear stiffness of a shear wall. The existing calculation methods of the shear stiffness considering the effect of the flexural stiffness of vertical studs are usually implicit and thus require numerical analyses. In this paper, we derive a simplified formula based on both mechanical equilibrium and the principle of minimum potential energy. The formula is verified by numerical static elasticity analyses.

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This paper studies seismic performance of reinforced concrete buildings under the effect of high wind. Three types of structures of earthquake-resistant construction, damper construction and base isolation construction, two types of seismic force of moderate earthquake and severe earthquake, and three different levels of wind load are investigated.
Following items were found through this study; in the case that buildings form plastic hinge mechanism, they deform into one-way and show poor energy consumption, so, their deformation remarkably increases, and this increase is controlled if the damper with the same strength as the wind load is installed in the building.

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Precast prestressed concrete (PCaPC) beams with a pretensioning system are often used for constructing long-span reinforced concrete buildings. It is important to clarify the bond characteristics of the prestressing strands, because the concrete is prestressed through the bond between the strands and the surrounding concrete. A bond test and a loading test were carried out to clarify the bond characteristics and the structural performance of PCaPC beams using large diameter strands. As a result, the anchorage length of strands for prestressing and after large deformation, and the load-displacement relationship of the PCaPC beam under seismic loading were clarified. Based on these results, it is concluded that large diameter strands can be used as prestressing steel in PCaPC beams.

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The purpose of this paper is to evaluate the energy absorption capacity of steel moment resisting frames considering randomness of member yield stress. It is well known that frames designed with weak beam strong column type mechanism show high ductility behavior, but the energy absorption capacity at the deformation level considered in the structural design process has not been discussed very well. In this paper, the energy absorption at the maximum drift angle of 0.02rad was investigated based on Monte Carlo simulation under the static load condition. The analysis parameters are the number of stories, the number of spans and column overdesign factor (COF). Some conclusions obtained by this study are summarized as follows. 1) Average value, 1% lower limit value and 5% lower limit value of the energy absorption increase by controlling the range of randomness of member yield stress, and 2) the increasing percentage is positively correlated with the number of stories. 3) COF can be made smaller than basic frames' COF by controlling the range of randomness of member yield stress, especially with large number of stories and high value COF.

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Investigated are the steel shear walls that have slits and are stiffened by wood panels. To examine the effects of various design parameters on the performance of the walls, a series of tests consisting of fourteen specimens are conducted. Material of stiffening panels, number of bolts to restrain the stiffening panels, coefficient of friction of the panel, and end detail of the slits are adopted as the test parameters. It is disclosed that the stiffness of the stiffening panels affects the degree of pinching in the cyclic behavior and the initiation and propagation of cracks initiated from the slit end controls the maximum strength. A good balance between the crack growth and out-of-plane deformation is found to be the key to achieve good performance of the walls as the shear resisting elements, and those stiffened by wood panels are more effective than those stiffened by steel panels.

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In our previous researches, it is shown that story drift concentration is restrained by columns in two braced frames with buckling-restrained braces. For the two story braced frames with buckled braces, it is possible for the column to distribute the shear force on each story over height and the story drift concentration may be restrained, if it keeps elastic. In this paper, the equations of the drift concentration factor for two story braced frames with buckled braces have been developed from the equilibrium conditions of the frames subjected to lateral force. This paper clarifies the mechanism of the two story braced frames and the relationship between the drift concentration factor and the ratio of column flexural stiffness. Finally, the drift concentration with seismic response analysis is estimated with the equation for static drift concentration.

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Vibration tests were performed in order to quantify horizontal movements of TSUKIISHIBU section in masonry wall subjected to dynamic horizontal load; the TSUKIISHIBU section represents the whole part of the masonry wall structure excluding corner part. A wall model was constructed by rectangular prism shaped masonry stones with kinds of slope on dry sand backfill and sinusoidal motion was applied on shaking table. The horizontal movements of masonry walls concerning such variables as slope angles, internal friction angles of stone blocks and back fill soil and input acceleration were calculated. As horizontal movements of masonry wall models show good agreement with calculated horizontal movements of the wall, validity of the theory for predicting horizontal movements of the wall is clarified.

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Results of an experimental study on the structural performance of EWECS columns under the varying or constant high compressive axial force are summarized in this paper. Under the constant high compressive axial force, EWECS columns become brittle with rapid progression of axial deformation, but under the varying axial loading, the deformation capacity of EWECS columns are considerably improved. In addition, the calculated ulitmate strength based on the superposed strength theory are very close to the exprimental values except for cases of varying low compressive loading.

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It has been known that plastic deformation of steel members causes thermal stress attenuation in a steel frame at fire. Although existing design guidelines consider this thermal attenuation behavior, design equations for estimating the ultimate strength of the frame do not directly consider the thermal stresses in the members. This is introduced based on a fact that the thermal stresses do not affect the ultimate strength due to the thermal stress attenuation. It should be noted, however, that this condition is only possible when the members have large plastic deformation capacity. To have better understanding of this thermal attenuation behavior, an investigation has been conducted in this paper on the structural fire resistance of a statically indeterminate steel beam at elevated temperature. Since the plastic deformation capacity is related in part to the strain hardening of steel, a relationship between the strain hardening and thermal stress attenuation is emphasized. Based on both theoretical and numerical analyses of the steel beam subjected to the thermal stresses, this paper clarifies that the strain hardening of steel plays an important role in attenuating the thermal stress; therefore the strain hardening contributes directly to improving the structural fire resistance.

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