This paper is intended to study the effects of the mix proportion on the Theological figures, strength and shrinkage ratio of the high-fluidity concrete sing portland blast-furnace slag cement and fly ash. The relationship between the mix proportion and the fluidity etc. of the concrete was investigated regarding several experimental factors such as kind of fly ash, mixing ratio of fly ash to portland blast-furnace slag cement, mixing ratio of super plasticizer, and so on. The Theological characteristics of the high-fluidity concrete such as plastic viscosity and yield value were measured by using the J shaped flow test. The main results on the fluidity are as follows. 1) In case of increasing the mixing ratio of Type I fly ash and Type II fly ash, the plastic viscosity and the yield value decrease. 2) The plastic viscosity and the yield value of the concrete which mixed Type II fly ash to 15% are smaller than those of the concrete using-portland blast-furnace slag cement with little addition quantity of super plasticizer.

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While concrete properties are influenced by curing temperature history, their variation can be described by a unique function by introducing a concept of equivalent age if the activation energy is rationally determined. In this study, cement paste, mortar and concrete are made with two types of cement, ordinary Portland cement and low-heat Portland cement. They are cured at a constant temperature of 20℃, 40℃ or 60℃ until the test age. Compressive strength, static modulus of elasticity, dynamic modulus of elasticity and fracture energy are determined. Determined values are compared with estimated values by means of the equivalent age and the conformity is evaluated. The estimated values were obtained by activation energy determined with measured values until 28 day. Then estimated values for 91 days are compared with the corresponding measured values. Furthermore, it is shown that coefficients in the estimation formula described as a function of curing temperatures achieve a higher precision for the estimation.

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In this paper, the macrocell corrosion rate was calculated using non-destructive test developed by the authors. Afterwards, the corrosion situation of the steel bar in existing concrete member was evaluated using calculated macroceU corrosion rate and microcell corrosion rate. As a result, the macrocell and microcell corrosion rate of steel bar embedded in existing reinforced concrete members such as hand rail or wall could be evaluated. Additionally, using this method, the influence of application of repair method or influence of temperature on corrosion rate of steel bar embedded in existing reinforced concrete member were evaluated.

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The quantity of carbon dioxide emission discharged from the intermediate processing of the construction waste is analyzed. At the first part, this study was carried out the questionnaire survey toward the intermediate processing plants of the whole country. The yearly quantity of carbon dioxide emission by the intermediate processing of the construction waste was calculated from this result. At the second part, result of the questionnaire survey was tidied in terms of processing methods and items to calculate the carbon dioxide emission per weight. By using these the calculation of the quantity of carbon dioxide emission can be simplified. And these estimated values can contribute to the reduction of the environmental impact as the guide to select the method of the intermediate processing of the construction waste.

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In this paper, first we measure microtremors of standard buildings in Kyushu University, most of which are low- and middle-rise RC buildings to obtain resonant periods. Buildings of national universities had been constructed under strong code and budget control so they are expected to be similar to each other. Next, stiffnesses of the buildings are inverted from resonant periods together with design documents. Then we construct nonlinear seismic response models based on the numerical models already proposed for RC buildings in Kobe (Nagato and Kawase, 2000). Finally we conduct damage evaluation for these buildings by using simulated strong ground motions for a hypothesized Fukuoka earthquake. We confirmed that the resonant periods of buildings linearly correlate with their heights but that the long-span direction tends to have shorter resonant period than the short-span direction. The effects of soil-structure teraction are negligible in the short-span direction and noticeable in the long-span direction. We confirmed that the average seismic performance of measured buildings coincides with the average performance of buildings in Kobe and that no RC buildings will be collapsed or heavily damaged even for the worst scenario of expected earthquakes at the site.

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After 1995 Hyogoken-Nanbu earthquake, buildings equipped with base-isolation systems are steadily increasing in Japan. However, large displacement pulses and large ground velocities have been observed in the near-source region of 1999 Chi-Chi earthquake in Taiwan and this kind of strong ground motions may cause a large displacement response in base-isolation buildings and may lead to severe damage and possible collapse. To counteract the excessive displacement response of base-isolation systems, we have developed a displacement control method of base-isolation systems using variable damping devices. This system is applied to a floor isolation system and the control performance is demonstrated by shaking table tests.

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Very few observational studies have been performed on rocking motions of slender seismically isolated buildings. The intent of this paper is to clarify the actual rocking mechanism of a slender isolated building by system identification analyses using earthquake response records. A parametric system identification technique proposed in this paper is applied to evaluate the structural properties of the building including the axial stiffness of isolators. The identification results suggest that soil-structure interaction affects the rocking motion of the building. Various numerical analyses are performed to confirm the soil-structure interaction effects.

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Horizontal subgrade reaction of a pile during soil liquefaction is investigated based on pile top vibration tests using a large-scale shear box. The subgrade reaction was resolved into elastic force and viscous force by back analysis using the Voigt model. It is shown that (1) the elastic force and the viscous force are independent of frequency under conditions which the displacement amplitude and the excess pore water pressure are constant ; (2) as the excess pore water pressure increases, the modulus of elasticity decreases much more than the coefficient of viscosity ; (3) the contribution of the elastic force to the horizontal subgrade reaction decreases with an increase in the excess pore water pressure.

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This paper describes simulation analyses of piled raft foundation under horizontal load. Two types of analytical model, 2D and 3D model, are used to calculate the horizontal resistance of piled raft foundations. 2D model is a simple model and consists of two dimensional beam elements of piles and Winkler's type of soil springs. 3D model is a hybrid type model combining three dimensional beam elements, an elastic half space and nonlinear joint elements inserted at raft/soil-pile interface. The simulation analyses are carried on three foundation types, the raft foundation, the pile foundation and the piled raft foundation, to estimate the horizontal behavior of piled raft foundations. From the comparison of analyses and in-situ loading tests, the following conclusions are obtained. The results of the simple 2D analysis are in good agreement with the experiment, where the spring constant in the analysis is evaluated from tests results. The simulation results by the 3D analysis explain well the horizontal behavior of not only the piled raft foundation, but also the raft foundation and the pile foundation.

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Applying Fourier series in a direction to the basic equations of linear static problems of cylindrical shells with arbitrary cross section, we may obtain ordinary differential equations with variable coefficients. Generally, it is hard to obtain their solutions with an analytical method. Applying Runge-Kutta method to them, we derive their fundamental solutions which let us obtain the shape functions of a strip numerically. Basing on the shape functions, we construct the stiffness and the mass matrices. Applying these matrices to static problems and natural frequencies analyses, we examine the characteristics of this procedure.

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Structural experiments of reinforced concrete columns were carried out using concrete with compressive strength of 100 to 180 N/mm^2, lateral reinforcement with nominal yield strength of 1275 N/mm^2 and longitudinal reinforcement with nominal yield strength of 685 N/mm^2. Those columns were tested under monotonic or cyclic centric compressive loads. From those tests it is found that lateral reinforcement of high strength steel enhances the compressive strength of the columns and improves the ductility of the high strength concrete with compressive strength of 100 to 180 N/mm2 effectively. Also from these results, the previously proposed stress-strain model of the confined concrete can be reevaluated as for the high strength concrete with compressive strength of 100 to 180 N/mm^2.

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For the purpose of comprehending the performance and the bond characteristics of reinforced concrete beam with all lapped splices in beam depth way at the critical region using U-shaped precast beam with longitudinal and transverse reinforcing steel bars, the authors performed cyclic loading tests for beams subjected to bending moment and shear force. In this case, the splicing reinforcing steel bars passed through beam-column joint are put on top of bottom bars(vertical splicing). As the result, it is clarified that 1) length of yield region was 1/2 of beam depth, 2) stress of main bar at end of lapped splice was evaluated by assuming the truss mechanism under the truss angle 45°, 3) the bond splitting strength of vertical splicing was evaluated by considering vertical binding force required to transmit bond force of splicing bar on the basis of assuming the truss mechanism and using the past evaluation of bond splitting strength.

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In low-rise or medium height RC buildings such as school buildings, the spandrel walls are often monolithically cast together with column. This type of column behaves like a short column in which shear failure is likely to happen. At present, in one of the important earthquake resistant design method, the spandrel walls are considered separate from columns by setting slit. As a result, the ductile flexural behavior may be expected because the shear span to depth ratio of the column becomes more longer. In this paper, two seismic retrofit design methods for RC column with spandrel walls are proposed without considering slit in design. In one method, only the ductility and in the other method, both the ductility and the lateral capacity of the column with spandrel walls utilizing high strength steel bars for prestressing and steel plates can be improved.

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This paper describes the evaluation method of hysteresis model for reinforced concrete beams and columns subjected to shear failure after flexural yielding. Deterioration due to cyclic loading after flexural yielding is modeled using the ductility factor at the start of deterioration μwy and factor representing the degree of deterioration A : μwy and A are determined based on the results of previous studies that focused on the shear deformation behavior and effectiveness of lateral reinforcement. As a result of comparison between the proposed model and test results, it is found that the model can accurately simulate the behavior of the member. Seismic response analysis is also carried out by single degree of freedom system using proposed model to identify the characteristics of response in the case of shear failure after flexural yielding.

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According to a regulation of performance formation for building design method, damage of reinforced concrete building should be controlled, such as a crack. Both of a crack generation and a residual crack width on a column need to be controlled. This study considered evaluation method of shear damage strength, i.e., to make the index of target value which makes the residual crack width on the column by introducing lateral direction prestress. Consequently, it is recognized from this study that the improvement of shear crack strength and shear damage strength on the column by introducing lateral prestress. Lateral prestress is so effective that performing not only for design which controls the shear crack width, but also the prevention design of the shear crack.

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This paper presents an analytical model for the simulation of steel braced frames in which both buckling and fracture of the braces are considered. The cross-section consists of many fiber segments, with each element taken to lose its resistance at the time of fracture. A sudden loss of resistance is converted to an immediate inertial force to maintain the overall equilibrium. The proposed model is applied to a three-story braced frame whose earthquake response behavior is examined for multiple near-fault ground motions. The effect of buckling on the maximum story drift is most notable with significant increases in the maximum story drift. The effect of brace fracture is found secondary particularly when the fracture occurs after buckling.

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1.序 1方向入力を受ける鋼骨組や鋼柱の振動実験が従来多くなされてきたが、2方向入力の振動実験や振れ振動実験に関する研究は少ない。本研究では1方向及び2方向の正弦波加速度入力を受ける角形鋼管柱の振動実験を行い、解析結果との比較を行う。また局部座屈、亀裂、加振方向、質量偏心及び幅厚比が応答に与える影響について考察する 2. 片持柱の振動実験 2.1 試験体 試験体は冷間成形角形鋼管であり、実験パラメータは幅厚比B/t、入力方向θ及び偏心比e^^-である。表1に測定寸法、幅厚比及び細長比を示す。試験体名中のSBはB/t=18.9、LBはB/t=31.8、Uは1軸曲げ、Bは2軸曲げ、Eは偏心による振れを受けることを表す。LB5UとLB6Bでは、試験部とベースプレートを隅肉溶接しているが、残りではベースプレートに穴を開けて試験部を通し、ベースプレートの上下端で隅肉溶接している。表2に固有振動数の実測値f_oと計算値f_o'、減衰定数力を示す。 2.2 載荷条件 表3に載荷条件を掲げている。降伏軸力と軸力の比である軸力比P/Pyは約0.025〜0.03であり、2軸曲げを受ける試験体の入力方向は45°である。最初に試験体頂部に重錘を置いて軸力をかけた後、徐々に正弦波加速度を入力し加速度振幅を増大させて、試験体を崩壊させた。 2.3 実験装置 図1は振動台上の実験装置である。図2に計測装置を複式的に示す。3個の変位計により試験体の変位及び捩れ角を、2個の加速度計、3個のひずみゲージにより加速度及びひずみを測定した。 3. 動的応答解析 3.1 解析モデル 解析モデルを図3に挙げている。柱脚部の長さdl部分のみ弾塑性変形が可能であり、残りを剛体と仮定した。図4は解析で用いた応力度-歪度関係である。 3.2 1質点系の運動方程式 図3の解析モデルのx、y方向の無次元化された運動方程式は式(4)で与えられる。運動方程式の数値積分にはNewmarkのβ法を用い、βの値を1/4とした。 4. 実験結果及び考察 4.1 SBシリーズ試験体 SB1U : 局部座屈が加振方向と直交方向の断面板要素に発生し、図5 (a)に示すようにy方向の抵抗力が徐々に低下した。最大耐力は破線で表されるメカニズムラインに達したが、y方向の加速度-変位関係のループは負側に寄っていった。SB2B : 45°方向の入力を受ける2軸曲げの試験体であるが、応答は比較的安定しており、x、y方向の挙動はほぼ同じである(図6)。初期段階で局部座屈による耐力低下が見られるが、その後の耐力低下は図5(a)のSB1Uに比べると小さい。SB3E、SB4E : 偏心比が応答に与える影響について調べている。SB3E試験体では局部座屈による急激な耐力低下が見られたが(図7(a))、SB4Eでは明瞭には見られなかった(図8(a))。いずれのケースでも、SB4Eの時刻歴が示すように、捩れ角は小さかった(図8(c))。SB4EはSB3Eに比べて偏心量が大きいため、耐力低下の割合や変形累積の程度が大きかった。 4.2 LBシリーズ試験体 LB1U : 局部座屈発生後、時刻歴における変位vの中心の移動が生じ(図9(e))、最終的には面外方向変位uが生じて崩壊する(図9(d))。LB1Uの挙動はSB1Uの挙動と似ているが、耐力低下はより大きい。1方向入力にも拘わらず面外方向変位が増大していく現象は、解析においても現れた。LB2B : 45°方向に加振されており、x、y方向の挙動はほとんど同じである(図10)。解析で得られた加速度-変位関係のループは、P△効果のためループは定常化しない。LB3E、LB4E : 2つの試験体の捩れ振動の挙動は良く一致しており、捩れ角も小さい(図11、12)。図7、8のSB3E、SB4Eの挙動と比較して耐力低下は大きく、また加速度-変位関係の正側・負側ピークの包絡線の勾配は異なっている。SB3Eで現れた急激な耐力低下はLB3E、LB4Eでは見られない。LB5U : 初期段階で局部座屈が発生し、耐力はメカニズムラインに達しない(図13(b))。また加振方向と直交方向の変位uが増大し崩壊した(図13(a))。柱脚隅肉溶接部において図13(b)の▼印の点で亀裂が発生した。LB6B : 柱脚溶接部に亀裂が発生し断画板要素にわずかな局部座屈が観察されたが、試験体は崩壊しなかった(図14)。x方向の耐力は喪失したが、y方向の履歴ループは最終的にスナップ型となった。 5. 結論 (1)1軸曲げの入力を受ける角形鋼管柱に面外変形が生じたが、これは面内変形がかなり進行してから現れた。(2)大きな幅厚比を有するLBシリーズの耐力低下の割合は、幅厚比の小さなSBシリーズより大きい。しかし両シリーズの全体的な挙動は良く一致している。(3)質量偏心の増加は最大耐力の低下、耐力低下の増大及び面外変形の増大を生じさせる。(4)1方向入力を受け亀裂を生じた試験体では面外変位が増大して崩壊したが、2方向入力時亀裂が生じた試験体では、x方向耐力を喪失したものの崩壊はしなかった。(5)解析は実験における面内の変形累積の発散傾向を概ねとらえているが、解析では局部座屈を考慮していないため、面外変形は発生していない。

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This paper shows the results of examinations of the hysteretic damping and the deformation profile along the height of full-scale test results of reinforced concrete box-shaped wall structures. The equivalent estimation method of the hysteretic damping is proposed and examined for the test hysteretic curves, which had not stationary loop. Then, the calculated hysteretic damping ratio of reinforced concrete box-shaped wall structures is discussed and summarized. The paper also concludes that the deformation profile along the height of a structure is estimated by considering appropriately the rotationed deformation in addition to shear and flexural deformations, and deterioration in flexural rigidity of simplified fish-born type models.

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Seismic response and damage of concrete filled steel tube frame (CFT frame) under extremely strong ground motion are calculated by the numerical analysis method presented by the author. The damage ratios of steel tube crack and local buckling of CFT column, which are closely related to the collapse of CFT frame, are obtained in relation with the distribution of story-shear strength, the column over design factor of frame and the concrete-to-tube strength ratio of CFT column. On the basis of the calculated damage ratios, the simple formula expressed by the design factors mentioned above is proposed to predict the ultimate earthquake resistant capacity of multi-story CFT frame.

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The boundary-value problem is formulated to predict the hydroelastic response of a mat-like floating circular plate advancing slowly in waves. The plate is modeled as an elastic plate with zero draught. The potential flow theory is employed with low forward-speed assumption. This allows the governing variables be expanded in a perturbation series of forward speed. Retaining the leading-order terms of the speed-dependent parts, the problem is reduced to two sets of boundary-value problems for the velocity potentials, for which analytical solitions are derived by applying the domain-matching method in cylindrical co-ordinates. The solutions may be useful not only to understand parametrically the fundamental nature of the forward speed effects (or equivalently, wave-current interaction effects) on the hydroelastic behavior of a floating circular plate but also to provide benchmark data for validating other numerical techniques for mat-like floating structures of arbitrary shape.

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A famous result for the damage in Tokyo Metropolis during the Kanto earthquake was that the damage rate of dozo (Japanese traditional timber storehouse coated with clay and plaster finish) is larger in the Yamanote terrace formed by diluvial deposit than that in the Shitamachi low-land by alluvial deposit, while the damage rate of wooden houses, which determined seismic intensity, was smaller in the Yamanote terrace than that in the Shitamach lowland. We re-examined the original data of dozo on the Kanto earthquake and compared with the damage data from the 1948 Fukui earthquake and the 1855 Ansei-Edo earthquake. It can be found that the original data was strongly contaminated by the damage due to fires during the Kanto earthquake, and that the result of dozo was not trusted. The damages of RC buildings and brick buildings which had almost the same natural period as dozo, were also re-examined. We could correlate weakly the damage rate of them with seismic intensity determined from the damage rate of wooden houses, which was larger on the alluvial deposit than on the diluvial deposit.

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