Based on the published papers, we investigate the influences of the properties of original coarse aggregate and the percentage of adhered mortar on the properties of recycled coarse aggregate concrete. And, the relationship between water absorption ratio of adhered mortar and compressive strength of original concrete and length change of recycled coarse aggregate concrete are analyzed. As the result, it is confirmed that compressive strength and length change of recycled coarse aggregate concrete are influenced by quantity and properties of adhered mortar.

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The clarification and modeling of fresh concrete's rheological performance is basically needed for realizing the workability design of fresh concrete. In this study we investigated experimentally the shear deformation of cementitious materials in fresh state using a stress growth method, and discussed the effects of fluidity, vertical pressure, loading rate, maximum size of particle, and volume concentration of solid particle. Then, we proposed a deformation model to describe the free deformation property of fresh concrete under shear stress. As a result, fresh concrete's shear deformation would experience suspension state, visco-elsto-plastic state and shear failure state with increasing shear stress, ant it shows different features in different stress state due to particles' contacts and dilatancy. Also, the fluidity of specimen and the vertical pressure produce great effects on the shear strain/ rate-shear stress relationships.

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In this study, the distribution of restraining ratio in concrete wall specimens with different shape, number of layer and span and so on was investigated by experiments and FEM analyses, in order to prepare eventually the material design method for controlling shrinkage cracking of RC structure. The following findings were obtained as the result. (1) The distribution of restraining ratio in walls should be considered by dividing into “edge area” in which Bernoulli-Euler's hypothesis stands up and “non edge area” in which this hypothesis doesn't stand up. Additionally, the same is equally true in the wall composed of multilayer and multi-span. (2) “Non edge area” appears when the length-to-height ratio of the wall is higher than some value. (3) The distribution of horizontal restraining ratio in “non edge area” can be calculated by replacing a wall with a uniaxial model.

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This paper describes the chemical deterioration of concrete by soaking up of boric acid solution. The results of the examination are shown as follows. (1) The Effect of concrete leaching which may occur by boric acid solution soaking into concrete on concrete erosion and mass change is small. (2) The influence of boric acid solution soaking into concrete on compressive strength and static elastic modulus of concrete is not notable. (3) The area of the chemical deterioration of concrete by boric acid solution soaking into concrete depends on the concentration of the boric acid solution and the soaking period. A higher concentration and a longer soaking period make the deterioration area larger.

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Construction sealant is the material to maintain the waterproof and airtight function by filling into joints. As sealants are exposed under conditions which are influenced by UV radiation, heat and rain etc., their degradations proceed in many sealants. The prediction of the weatherability is important for the sealant performance. Many studies have been carried out to predict the weatherability for the correlation between outdoor and accelerated exposure of construction sealants. In this study, the estimation of the weatherability of construction sealants has been tried based on their weatherability by outdoor exposure.

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In this paper, passive control design for linear viscoelastic damper system is extended to that for nonlinear viscoelastic damper system. The nonlinear damper is replaced to Kelvin model having same equivalent stiffness and damping based on the steady state hysteresis reaching the peak response. This equivalent linearization rule is verified using time-history analysis of SDOF models. Simplified theories on seismic peak response evaluation and preliminary design of the viscoelastically damped building based on SDOF idealization are introduced. The verification of the accuracy of design approach is demonstrated via time-history simulations.

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A series of shaking table tests on a high-rise building are conducted in order to acquire realistic data on the damage. The adopted test system consists of a lower part represented by four-story steel frame structure and an upper part simplified by substitute layers made of concrete mass and rubber bearings. In the tests using long period ground motions, the specimen is subjected to large cumulative inelastic deformations as well as large inter-story drifts. Such seismic loads are represented by total input energy to the specimen. The total input energy from each test is plotted in the corresponding energy spectrum of the input wave, indicating reasonable correlations. The beam ends dissipate ninety percent of the total input energy of the steel frame. The results characterized by input energy and its distribution suggest the adopted measuring methods reasonable. The seismic performance assessment in terms of input energy can be developed not just for a seismic design but also for damage monitoring techniques.

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Although the energy transmitting boundary is a very accurate and useful technique for the earthquake response analysis of the soil-structure interaction system, it could be applied only for linear or equivalent linear analyses in the frequency domain. In the previous paper, the author proposed an earthquake response analysis method using the energy transmitting boundary in the time domain. In that analysis, the inner field can be treated as the nonlinear system. Contrary to this, the nonlinear transmitting boundary is proposed in this paper. By using it, all of the inner field, the outer field, and the boundary itself can be treated as the nonlinear system. After its concept and analysis method were explained, the efficiency of the proposed method are confirmed by some example problems.

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The author has studied and proposed transform methods of frequency dependent dynamic stiffness into time domain. Although various kinds of stiffness got to be transformed by the methods, some problems were still remained. In this paper, followings two problems were studied. First, the relation between the proposed transform methods and the Duhamel's integral was studied in order to understand the meaning of the 2 series of impulse responses obtained by the methods. Next, to expand the applicability of the methods, the time domain transfer function, obtained by the transform of frequency domain transfer function, was shown. The seismic response values are easily calculated in the time domain using the function without FFT. The efficiency of the function was confirmed by a practical example problem.

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In this paper, a simplified seismic assessment procedure for asymmetric frame building considering the critical direction of seismic input at each nonlinear stage is proposed. In this procedure, the critical direction of seismic input which produces the maximum response at flexible side frame is assumed to coincide with the principal direction of the first modal response, which is evaluated based on pushover analyses results at each nonlinear stage, and the peak response of flexible side frame at each seismic intensity is estimated based on equivalent linearization technique. The results show that the upper bound of peak responses at flexible-side frame by given seismic intensity and arbitrary direction of seismic input can be predicted by the results obtained from proposed procedure.

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This study presents the practical assessment of a relative story displacement sensing system verified through the forced vibration test on an actual three-story building. In the sensing system, we apply two noncontact-type sensors utilizing position sensitive detectors (PSDs) and phototransistor arrays (PTrs). They are installed between each adjacent pair of floors, and they can directly measure the relative story displacements. The basic features and their applicability are discussed by analyzing the measurement records from sensors. The results show the effectiveness of the sensing system under realistic conditions, and clarify the issues to be improved in its applications to the structural health monitoring system.

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In tall structure, the vibration suppress structure that the damping material which absorbs the earthquake energy is used the each level in the building is a main stream. Also, the low yield point steel is used a number of damping material. Because the low yield point steel is plastic-rise by beside a small and medium-sized earthquake or the strong wind and the typhoon, the security safety for external force by the wind is important. Currently, Miner's law is widely used as estimation method of fatigue life when stress amplitude varies such as actual load. However, many studies are reported that the estimation of fatigue life the use of Miner's law overrate fatigue life. In this report, we investigate applicability of cumulative fatigue damage D from experiment on the material of low yield point steel. As a result, it is show that relation of D-ΔN and the minimum of D have 0.34. In addition, that relation varies from control technique to control technique.

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An improved semi-rigid connection system which is used to connect a pile head and a pile cap has been proposed by authors and it has proved to be effective to reduce bending moment of a pile head under general level of axial load. However, in recent years, high bearing capacity piles, which have more than twice capacity of general piles, have become widely used. To investigate performances of the proposed system under such a high axial load, full-scale structural tests are conducted. From the test results, it is revealed that the maximum bending moment at a pile head (M_max) almost agrees with a maximum eccentric moment (M_e) under low axial stress, but M_max/M_e decreases with axial stress increase. This paper proposes an experimental formula to evaluate M_max using M_e and axial stress ratio (σ_n/σ_B, σ_n : axial stress at a pile head, σ_B : concrete strength of a pile cap) under the condition that a pile cap isn't damaged with strength decrease, and an analytical method to judge the condition of its application.

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Strong motion records of 2007 Niigata-ken Chuetsu-oki earthquake were examined in order to evaluate ground motion characteristics of the earthquake. Ground motions observed at Kashiwazaki Kariwa Nuclear Power Plant site were significantly larger than the response spectra evaluated on the basis of Noda et al. (2002), and the level of the ground motion observed at Arahama area (unit 1-4 side) was approximately twice as large as that at Ominato area (unit 5-7 side). Observation records of the offshore events other than the eathquake were also larger than the response spectra based on Noda et al. (2002), whereas records of the inland events were smaller than those. In addition, these characteristics were also observed in the vicinity of the site through the analysis of the ground motion records obtained by KiK-net.

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The post-buckling hysteresis model for the braces under cyclic axial force proposed by M.Wakabayashi, M.Shibata and others are popularly used for time-history analyses for braced frames. Also the authors have proposed easy evaluation method predicting the fracture point of the braces after local buckling. However, these methods are derived from pin-ends boundary conditions, and performances under rigid or semi-rigid conditions are not made clear yet. In this paper, detailed FEM analyses of H-section braces under various rigidity conditions are carried out, and parameters for post-buckling hysteresis model are identified. Also prediction method of fracture points for braces under various boundary conditions is proposed.

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In this paper, we propose tuned mass dampers with initial displacement to control transient response for spatial structures. The initial displacement of the TMD changes the phase of a beat envelope curve resulted from two vibration modes with closely spaced natural frequencies. We propose design formulas of tuned mass dampers with initial displacement and studied analytically the effect of vibration control on an impulse force and an impulsive earthquake force. As a consequence, we could recognize that the proposed system improve especially the control performance of the initial response. Lastly, to confirm the applicability of the proposed design formulas for controlling real structures, we studied analytically the effect of vibration control of the proposed method in this paper by using a single layer lattice shell model.

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This study intends to estimate bending strength of laminated timber beams considering location and size of knots. This paper makes a proposal of the bending strength models for laminated timber beams considering location and size of knots. The validity of its proposal models is registered by experimental test. The calculation results of the Monte Calro simulation using its proposal models is well accorded with experimental results. Its proposal models give an account for the reinforcing effects by lamination. It is presented that the influence of location and size of knots in bending strength varies according to distribution of load and beam span.

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Elastic moduli and strengths of plywood and constituent veneer partly including the effect of adhesive are investigated by means of material tests and theoretical analyses. The material tests consist of tension, compression, and shear under in-plane loading. It was found that the elastic moduli of plywood are well predicted from those of veneer constituting the plywood by the theory of anisotropic elasticity, in that the plywood as well as the veneer was identified orthotropic and the effect of glue layers was observed considerable. The strengths of plywood in the principal axes were also well predicted by the common strength criteria of orthotropic plates. However, the strength of plywood in an inclined direction to the principal axes did not agree with the conventional Norris's and Tsai-Hill's criteria, because the fracture mode is different from that assumed in such criteria. The fracture path caused by the inclined directional loading is not a single line, but alternate lines associated with the shear fracture of the adhesive layers. This observation brought another method of strength evaluation for plywood, which gave a good agreement with the test results.

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In order to investigate the tension-stiffening effect of reinforced Engineered Cementitious Composite (ECC), which is one of the High Performance Fiber-Reinforced Cementitious Composite (HPFRCC), uniaxial tension test is carried out for the specimens with one deformed steel rebar arranged. Bond analysis between ECC and rebar, in which fiber bridging effect of ECC at crack is considered, is conducted under the assumption of the bond stress - slippage relationship. Analysis results show that the tension-stiffening effect between ECC and steel rebar is relatively small rather than bridging action of ECC. It is also confirmed that bridging stress is smaller than crack strength of ECC as the average and strain capacity of ECC increases due to restriction of crack localization.

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Seven half-scale post-tensioned precast concrete beams were tested under anti-symmetrical flexure. The experimental parameters were shear span ratio and shear reinforcement ratio. Multi-strands and high strength shear reinforcement with nominal yield strength of 785 MPa were used as post-tensioning steel and shear reinforcement, respectively. Yielding of shear reinforcement was not observed in any of the specimens. The flexural capacity evaluated by the ACI rectangular concrete stress block with plane section assumption agreed well to the experimental results. The shear capacity was estimated by the design equation 71.2a in the AIJ Standard for Structural Design and Construction of Prestressed Concrete Structures. The experimental results collected by literature survey to past research revealed that shear failure modes could be related to each of the experimental parameters (shear span ratio, shear reinforcement strength and shear reinforcement ratio).

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When subjected to long period ground motions, high-rise buildings would sustain large cumulative inelastic deformations. Beam-to-column connections with RC floor slab are tested to examine the existing performance and effect of seismic retrofit of existing high-rise buildings. Four field welded beam-to-column connections are prepared in reference to the details of high-rise buildings built in 1960s-1970s. Three types of retrofit are adopted for the beam ends, namely welding along the shear plate, attachment of wing plate haunches, and attachment of a vertical haunch. For the unretrofitted connection, presence of a floor slab is attributed to the fracture in the bottom flange. The three retrofitted connections showed three different failure modes. A plastic theory is applied to interpret the resisting mechanisms, indicating reasonable correlation with the corresponding test results.

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A shaking table test of full-scale 4-story building was conducted at E-Defense in order to evaluate the structural and functional performances of a steel frame not only under design level but also under ground motion over design level. This paper presents the collapse behavior of a steel frame after steel members reached the maximum strength. The collapse mechanizm was changed from the whole-collapse type to the story-collapse type by deterioration of columns caused by local buckling. Finally, the specimen collapsed at the first story by Takatori original records. From a series of results, the detail data of collapse behavior is obtained.

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The authors have proposed and developed the buckling-restrained braces (BRBs) providing stable hysteretic behavior under high-strain conditions. In the past studies by cyclically static loading tests, the performance evaluation formula of the BRBs was proposed with the scope of practical application. However, the effects of the clearance between the steel core plate and the restraining member on the inelastic behavior of the BRBs have not been determined yet. In this paper, the effects of the clearance on the hysteretic behavior and compressive strength of the BRBs are examined by cyclically static loading tests. As a result, their effects are not significant to the compressive strength and the deformation amplitude of the buckling mode of the BRBs. Furthermore, the number of the buckling mode shape related the compressive strength is estimated.

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After the 1995 Hyogoken Nanbu Earthquake, fractures at welded beam-to-column connection have been one of the most serious concerns. To avoid the fractures, various alternatives have been proposed, and the connection with exterior diaphragms is considered as one solution because of significant reduction of welding. The connection proposed in this paper is a type of the exterior diaphragm system. A portion of the floor slab around the column is cast by SFRCC, which is one of the ultra high-strength concrete, and the slabs are connected to the beams by a group of headed studs. In the connection, the beam hinge is expected to form at the edge of SFRCC diaphragm. To realize the system, the studs have to be arranged in small spacing near the column, which is made possible by the large bonding characteristic of SFRCC. Full scale tests on the new connection are conducted for cyclic loading. The tests show that the connection failed by beam yielding as expected, and the beam strength reached 1.2 times the beam plastic moment.

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This paper proposes prediction methods of the maximum in-plane shear force acting on floor slab for transmitting to plane frame the inertial force due to earthquake. And, time history response analysis are conducted, in order both to confirm prediction methods and to verify effects of structural parameters on the maximum in-plane shear force. As a result, following conclusions can be obtained; (1) the maximum in-plane shear force converges to the value of the rigid floor slab after indicating the maximum value, as in-plane stifness of floor slab becomes larger, and (2) proposed prediction methods agree with time history responses qualitatively.

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Theoretical studies are presented on the prediction of bending strength of a wide-flange beam-column subjected to bi-directional bending. This study has two main objectives. The first is to find the influence of the out of plane disturbance to the design of a beam-column subjected to bi-directional bending. The other is to propose design formula. When the P-δ effect predominates, the column collapses at the mid-span, otherwise the column collapses at the member end. Bending strength of a beam-column subjected to bi-directional bending is obtained as the smallest value among the loads corresponding to collapse at the end or at the mid-span. Proposed formula shows a good agreement with precise numerical solutions and/or experimental results.

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To clarify the shear behavior of the inner panel for RCS system, twelve specimens were tested under monotonic loading. The experimental variables were the thickness of the face bearing plate, the length of loading region and so on. From the test results, it was shown that ultimate shear strength was affected by the thickness of the face bearing plate and the steel flange. An analytical model of the inner panel failing in shear was proposed. This model was composed of two elements, that is, web panel and concrete panel surrounded by the face bearing plate and the steel flange.
Based on this model, analytical formulae were proposed. It was shown that the predictions were in good agreement with the test results.

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This paper describes elasto-plastic behavior of the column-to-column joints composed of steel members by filling the joint with concrete or mortar. The three series of tests were carried out using column joint specimens subjected to cyclic lateral loading. The test results verified that the joints could be regarded as rigid. If the mortar did not crush, the joint could transfer the ultimate moment of the columns. The analysis employing the yield condition of Mohr-Coulomb is applied to estimate the yield strength and maximum strength of the connections. The formulae of the strength are verified through comparison with test results.

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The vulnerability functions which express the relationships between damage ratios of household goods and seismic intensities of floor responses have been developed from the results of questionnaire surveys for recent five earthquakes. It has become cleared that the damage ratios of household goods of five earthquakes are relatively equal, if they are classified according to the structural damage levels of buildings. Then, the developed vulnerability functions of household goods are classified into three structural damage levels of buildings. Using the developed functions, seismic damage of household goods can be easily estimated for each family and for various earthquakes.

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