This report studied effects of applying ultrasonic waves on concrete in mixing works, by measuring compressive strength, slump, and air content, and by investigating the microstructure of the hardened concrete. The results showed the increase in compressive strength, but little influence on slump and air content. It was also observed that the microstructure became more dense, especially in the interfacial zone between aggregate and cement paste.

抄録全体を表示

This report shows experimental results for the influence of porosity of high-strength lightweight concrete upon properties of hardened concrete, such as compressive strength, fire resistance, freezing and thawing. These results are as follows ; (a) In regard to inner porosity of lightweight aggregate, it was observed the tendency that expanded shale type has a lager radius than that of sintered fly ash type. In case of the large sized aggregate, this tendency is more evidently, and the influence of radius size of porosity and aggregate is confirmed at high strength area, (b) The extent of influence of curing methods for porosity of this type concrete differ from shape and size of specimens, (c) Compressive strength of concrete is evaluated by effective pore volume under any curing condition, but these relationships depend on types of aggregate, (d) Resistance of freezing and thawing or fire of light weight aggregate concrete is not necessary to advance under moisture condition, because of light weight aggregates, due to their cellular structure, capable of containing more water than normal weight aggregate, (e) Fire resistance of high-strength concrete is lower than that of normal-strength concrete. The safety range of fire resistance is confirmed by water content and medium pore radius of concrete.

抄録全体を表示

This paper presents a method to evaluate the slipperiness of floors and pavements from a viewpoint of safety on riding a bicycle, which is based on the relation between the evaluating scales of slipperiness and slipperiness index (C.S.R-BIKE), measured with developed slip meter reported in part2. The outline of this study is as follows. The first, the evaluating scales of safety of slipperiness were made by sensory test by means of floors and bicycle. Then, the C.S.R-BIKE of floors was measured with the developed slip meter. Based on the relation between the evaluating scales and the C.S.R-BIKE, evaluation index and evaluation method of slipperiness of floors and pavements from a viewpoint of safety on riding bicycle was presented.

抄録全体を表示

The purpose of this study is to find physiological parameters about fatigue during standing, then to consider a correlation between fatigue and hardness of floors. Three fatigue tests were taken place during female subjects kept standing 90〜180 minutes. At fatigue test I, tow parameters which had a possibility to correspond to fatigue were selected among eight parameters. Furthermore one parameter as called number of step changing which had a possibility to indicate the different response among different floors was decided among tow parameters detected throughout from fatigue test II. Then, with results of fatigue test III, the correlation between fatigue and hardness of floors was presented by means of decided physiological parameter.

抄録全体を表示

In Part2, we designed two types of stain accelerating devices. In this Part, we adopted the device which we thought would reproduce stains closer to the real stains and made a sensory test on materials exposed to the air in a smoking room and materials stained by the device. After careful consideration of the results of the sensory test, we created the evaluating scale for cigarette smoke stain, and concluded that the physical quantity (color differential + 〓b^*) indicated the state of stain (〓b* : the change quantity of the CHROMATIC index of stained and un-stained materials). In what follows, we will show a way of evaluating cigarette smoke stain on the basis of the relationship between the stain evaluating scale and the physical quantity of materials and present the evaluation index and the evaluation method for stain.

抄録全体を表示

The purpose of this study is to present the lower criterion of C.S.R not to slip at the landing when people step on the slippery surface without the knowledge of the slipperiness changing. In this paper, first, it was made clear that the most dangerous motion was fast walking at the speed of one-point-two-two times the height per second. So, fast walking and walking at natural speed were selected as motions to be investigated. Secondly, from the investigation of the load applied to the floor while these motions, the load to be simulated by "Landing Slip Meter" was established.

抄録全体を表示

This study evaluates live load intensity that is independent of structure type. Live load intensity was calculated for six uses : dwelling, hotel room, classroom, office, theater with fixed seats and library stack room. A model was investigated for each. The room areas were divided into similar units, and the live load was calculated for each unit. These models are classified into types on the basis of their use. For example, in dwellings, most furniture is concentrated along walls while in classrooms and theaters it is distributed uniformly over the whole area. Thus, the live load intensity model varies depending on the type of use. In conclusion, it is possible to estimate live load intensity with these models, and the result can be applied in the analysis of large span structures and in checking for cracks.

抄録全体を表示

This paper proposes the method to estimate a structure coefficient Ds based on displacement response. First, estimation formulas of displacement response are evaluated for the bi-linear type design velocity response spectrum using the equivalent linear method. Next, the method to determine a value of Ds is proposed by using the estimated displacement response. Finally, trends of the values of Ds determined here to the initial period, energy absorption ability, and allowable deformation are investigated. They have the following tendencies. 1) Increase like a hyperbola having the upper limit along with the reduction of the period ratio TR. 2) Reduce like straight line along with the increase of equivalent viscous damping coefficient β. 3) Reduce like straight line or like the exponential function having the upper bound along with the increase of allowable ductility factor μ.

抄録全体を表示

This paper presents a numerical method for the analysis of the free vibration behavior of arbitrary shape strip plates by using the Rayleigh-Ritz approach, together with some numerical results. The method is based on the arbitrary curved coordinate system using a infinitesimal deformation theory. Numerical results are compared with the available ones in the literature and in the F.E.M. The comparison shows the method presented in this paper is useful for analyzing the free vibration of arbitrary shape strip thin plates.

抄録全体を表示

This paper presents the methodology for H^∞ structural controller re-design based on an identified structural model with AMD providing a random input. The transfer function of the controlled structure is identified by mean of linear regression model-based relationship between input and output. The identified transfer function provides us with the natural frequencies, damping ratios and reduced-order modal matrix with the same dimension as the number of output-measured stories. Based on the obtained model of the structure, H^∞ controller can be re-designed. The effectiveness of this methodology is demonstrated by conducting computer simulations for a 20-story building. This methodology could be also applied to other theory-based controller than H^∞.

抄録全体を表示

1.序論 建築骨組構造では、空間を仕切るために壁要素(Infill Wall Element)がよく使われる。骨組要素が壁要素を含む場合、その骨組を壁付骨組と呼ぶことにする。多くの発展途上国ではこのような壁付骨組構造が広く用いられている。壁要素にはいろいろな材料が用いられる。例えば煉瓦やコンクリートブロックなどである。実際の設計では多くの場合壁と骨組はモルタルの付着だけで結合される。壁付骨組の地震時の非線形挙動については不明な点が多く、明確な設計指針もない。通常壁要素は非構造部材として無視される。そこで本論では壁付骨組の耐震性能を近似的に把握するために、非線形地震応答における骨組の累積塑性エネルギー及び塑性率の期待値と標準偏差を単純な数式で表現することを目指す。またそれを用いて壁付骨組の耐震信頼性を評価する。2. 要素の履歴モデル 壁要素の履歴モデルを図1(b)のように設定する。壁要素の脆性的特性は降伏後の負剛性で表されている。剛性の低下は強度の低下に比例するとする。支配パラメータは初期剛性(K_<w0>)、降伏強度(Q_<wy>)、及び降伏後の負剛性(βK_<w0>)である。骨組要素の復元力は、図1(c)に示すバイリニア形とし、塑性剛性はゼロとする。支配パラメータは初期剛性(K_<f0>)と降伏強度(Q_<fy>)である。二つの新しいパラメータR_k(=K_<fw0>/K_<f0>)、とR_q(=Q_<fwy>/Q_<fy>)を定義する。ここで、K_<fw0>=K_<f0>+K_<w0>及びQ_<fwy>=Q<fy>+Q<wy>である。壁付骨組の復元力は壁要素と骨組要素の復元力を足したものとする。壁要素の損傷に応じて荷重が壁要素から骨組要素に移り、壁要素の完全破壊後は壁付骨組の挙動は骨組だけの挙動と同じになる。 3. 非線形応答解析 一定のパワースペクトル密度関数をもつ平均値ゼロの定常ホワイトノイズを入力加速度とする。それを静止している非減衰1自由度系の基部に作用させる。骨組要素の強度に対する入力の強度の比に相当する無次元量なを定義し、その値の範囲を0.0125〜0.05とする。過去の関連する実験データを参照して、R_k=1,6,8,..,14、R_q=1.0,1.4,1.5,..,2.0、β=-0.05,-0.10,-0.20と設定する。R_k=1.0、R_q=1.0は骨組要素のみの場合に相当する。骨組要素の無次元累積塑性エネルギーλの期待値と標準偏差(λ^^-、σ_λ)及び塑性率μの期待値と標準偏差(μ^^-、σ_μ)に着目する。それらは固有周期で無次元化された時間τに依存する。λ^^-とτの関係は一般に図3のようになり、(2)式のように書き表すことができる。シミュレーションの結果を参照して、式中のτ_cを(3)式の形に仮定する。右辺の第1項は骨組要素だけの場合のτ_cの値を表し、ξのみの関数である。第2項は壁要素の影響を表す項で、ε/ξとβの関数となっている。ここで、εは図1(c)の影のついた四角形の面積に対する(b)の三角形の面積の比である。式中の定数を数値解に最も合うように決めると、図2のようにλ^^-の表現式は数値解とよく一致する。μ^^-,σ_μ,σ_μについても(5)式のように(2)式と同じ形式を仮定し、式中の係数a_i、b_iもλ^^-の場合を参照して、(6)、(7)式で表現する。式中の係数を同様に数値解に最も合うように決めると、図4、5のように表現式は数値解とよく一致する。以上の表現式中の係数を一括して表1にまとめる。重要なことは、骨組要素の応答はξに依存し、壁要素が骨組要素に与える効果は、ε/ξとβの関数として表されるということである。図5から分かるようにβそのものの影響はあまり大きくないが、εはβに依存する。結局ε/ξが壁要素の効果を表す最も重要な指標となり、この値が大きいほど壁要素が骨組要素の応答をより小さくする。 4. 信頼性解析 無次元累積塑性エネルギーまたは塑性率がそれぞれある規定された値λ_Fまたはμ_Fを超えない確率を信頼性関数R_λ(λ_λ)またはR_μ(μ_F)と定義する。信頼性関数は(8)、(9)式のように対応する確率密度関数を積分することによって得られる。確率密度関数として対数正規分布、ガンベル分布及びガンマ分布の三つを仮定し、すでに得られた表現式を用いて信頼性を評価してみる。その結果によれば図7のように信頼性は確率密度関数の分布形にあまり影響されないことが分かる。そこでλとμの信頼性関数を近似式で表される期待値と標準偏差をもつガンベル分布であると仮定し、シミュレーションによって求められた信頼性関数と比較する。その結果の例を図8、9に示す。近似解と数値解はよく一致していることが分かる。骨組要素の信頼性は、ξが大きいほど小さく、ε/ξが大きいほど大きい。 5. 結論 脆性的要素(壁要素)を含む骨組の非線形地震応答の特性と信頼性について考察した。壁要素は降伏後に負の剛性となる履歴特性をもち、骨組要素は完全弾塑性形履歴特性をもつとした。壁付骨組構造を非減衰1自由度系にモデル化し、定常ホワイトノイズを入力加速度とした非線形地震応答解析を行った。得られた結論は次のようにまとめられる。 1. 骨組要素の無次元累積塑性エネルギー及び塑性率の期待値と標準偏差の近似解をすべて同じ形式の単純な関数で表現し、それらを用いて信頼性解析も行った。シミュレーションの結果と近似解は実用的に許容できる範囲でよく一致した。 2. 壁要素が骨組要素の応答に与える影響は、ε/ξとβの関数で与えられる。ここでεは骨組要素の弾性限歪エネルギーに対する壁要素の歪エネルギー容量に相当するような量であり、ξは無次元入力強度、βは壁要素の負の塑性勾配比を表す。とくにε/ξが壁要素の効果を表す重要な指標である。

抄録全体を表示

This paper aims at presenting the effectiveness of providing a low to mid-rise building with a soft first story subject to active or semi active control against seismic excitations. The control is based on the sliding mode control theory, in which sliding surface is so designed as to shift in accordance with the seismic acceleration, improving greatly the effects on displacement reduction. It is confirmed by earthquake response analysis of a five-DOF shear model that both an actuator and a capacity adjustable viscous damper is available for the purpose.

抄録全体を表示

Viscoelastic dampers (VE dampers) have been used in the earthquake-resistant and wind-resistant design of tall buildings for about 30 years, because they have strong damping effect against from small to large vibration. After Northridge earthquake in US A 1994 and Hyogoken-Nanbu earthquake in Japan 1995, viscoelastic dampers, as a part of passive energy dissipation system, are getting more attention in the seismic design of building structures. However, the mechanical characteristics of viscoelastic material are very sensitive to the temperature of VE material and frequency of structural system, the mathematical formulation of hysteretic model is too complex and difficult to be used directly in the actual dynamic response analysis. This paper presents the determination method of elastic stiffness k and damping coefficient c for the simple Kelvin-Voigt model based on the results of dynamic loading test of VE dampers. In order to use the Kelvin-Voigt model and the empirical formula of elastic stiffness k and damping coefficient c directly into the time history response analysis, a new concept of transient frequency is proposed in this paper. It is confirmed that, the proposed simple model has good agreement with the results of random dynamic loading tests.

抄録全体を表示

As arise great demands for maintenance of functions and protection of properties, recently many base isolated buildings have been constructed. Depending on the geometrical shape and occupancy type of buildings, mid-story isolation system is more suitable than conventional base isolation system for some buildings. Therefore, it is necessary to shed light on the seismic behavior for buildings with the mid-story isolation system. For the mid-story isolated buildings, nonlinear time history analyses as well as modal analyses with equivalent linear model were carried out. As the results, it is concluded that the mid-story isolation system is effective in reducing the seismic response and if the effect of higher modes related to the location of isolation devices can be properly evaluated, the proposed system is considered to be one of the efficient choices in the seismic design.

抄録全体を表示

Analytical studies concerning lateral seismic earth pressure on a building model are summarized as follows. 1. Lateral earth pressure on a deeply embedded building model during an earthquake is composed of relatively long-period lateral earth pressure with the same phases on opposite sides and short-period lateral earth pressure with reversed phases on opposite sides, of which period is shorter than the fundamental natural frequncy of the building. 2. The observed characteristics of lateral earth pressures, concerning amplitude and phase, can be well reproduced by multi-input analysis based on the observed waves under the ground. 3. Amplitude and phase of lateral earth pressure are remarkably influenced by the incident angles of input motions. The observed amplitude and phase of lateral earth pressure are well reproduced by analyses with the assumption of 5 to 10 degrees as the incident angle of input motion. These angles are coincident with the general incident angles of actual earthquakes.

抄録全体を表示

A seismic hazard map, indicating the regional distribution of expectancies of ground motion intensity, has to be constantly updated in tandem with advances of seismology and earthquake engineering. In this paper, the authors propose to make out a new seismic hazard map of Japan, drawing on the recent results of studies relating to the maximum magnitude model of active faults, the modified attenuation formula of ground motion amplification based on the Digital Nation Land Information. The authors in conclusion show the distribution of expectancies of ground motion velocity in a 500-year period for the entire Japanese archipelago.

抄録全体を表示

New stress functions introduced by prof. Tosaka and prof. Sueoka for expressing stress components at a point in three dimensional elastic body are used in a theory of plate bending including the effect of transverse shear deformation. Two conditions of compatibility are obtained as governing differential equations expressed by new stress functions. Displacement components and resultant stress components acting at a point of section of the plate obtained by employing double trigonometric series agree with these obtained by using displacement method in expression. It is shown that numerical results of displacements, bending moments and shearing forces for a uniformly loaded rectangular plate with two opposite edges simply supported, the third edge clamped, and the forth edge free, agree with calculated results by employing displacement method.

抄録全体を表示

The fuzzy design problem of building structures which satisfy the specified grade is formulated. (1) By using the solution to the corresponding optimum crisp design problem, the determination method of fuzzy constraint for object function is presented. (2) In this problem, the design variables are fuzzy numbers and α-level set of fuzzy theory is used. (3) The solution to this fuzzy problem is derived directly from the solution to the corresponding optimum design problem of crisp numbers. By selecting the members out of the the range of fuzzy solutions, building structures which satify the specified grade can be easily designed.

抄録全体を表示

In the present study, we conducted out the flexural test of column corresponding to the first story in tigh rise frame consisted of precast concrete syructure, in order to investigate the mechanical behaviors under seismic load. This paper aims at evaluating the ultimate flexural capacity of a precast concrete column connected by grout-filled coupling sleeves for the steel bar with high strength. By using the theory of compressive struts constituted in precast concrete column, the model on tie action and arch action is conducted and its conformity to experimental results is verified.

抄録全体を表示

Equations to estimate buckling strains of compressive longitudinal reinforcement arranged in confined concrete are derived, through discussions on results of our experimental studies. In the tests of confined concrete with longitudinal reinforcement under uniaxial compressive loading, effects of following factors on the buckling strains were investigated, such as ratios of lateral reinforcement pitches to specimen diameters (S/D), an index of confining stress (ps σ sy), yield strength of the lateral reinforcement (σ sy), shapes of lateral reinforcement, compressive strength of plain concrete (Fo), diameters of longitudinal reinforcement (φ) and locations of longitudinal reinforcement Comparisons between test results of budding strains and estimated ones show that the derived equation has successful applicability about ± 30%.

抄録全体を表示

We've checked the present AIJ design formula to estimate shear strength of SRC members referring the database of experimental results, and clarified the problem. There are two types of design formulae to estimate shear strength based on the theory of plasticity. The one satisfies the equilibrium condition among flexural force, shear force, and axial force, and the other doesn't satisfy. The former type agrees with the theory, and fits in the purpose of calculating the strength of designed members. The latter type fits in the purpose of calculating the amount of steel bar necessary to resist the given external force. First we've proved that we could estimate the ultimate strength of SRC members as same as RC members by the former. In the second place, we've proved that we could construct the design formula to estimate shear strength by the latter.

抄録全体を表示

This paper reports an evaluation method for the shear strength of interior joints consisting of steel beams and reinforced concrete columns. The shear strength is generally calculated by the sum of the nominal shear resistance of a steel web panel and concrete elements. In this paper, the shear strength is calculated in consideration of the relation between the shear crack and the maximum strength of beam-column. Design equations presented herein are evaluated through comparison with existing experimental results. The comparisons between experimental and calculated results indicate an excellent agreement.

抄録全体を表示

Recently, the development of coastal zone has been advancing, and the chance of human activity has increased near the sea. On the other hand, destruction of ozone layer has resulted in an increase in the amount of ultraviolet radiation reaching the earth surface. The human body is harmfully influenced as skin cancer and eye damage by ultraviolet radiation. Especially, the effect of ultraviolet radiation on beach is higher than that inland area due to the reflection from the sand surface. This report shows measurement method of ultraviolet reflectance on wide sand surface using ultraviolet radiation camera and reflection standard board. From the measurement results, the ultraviolet reflectance on sand is from 3 % to 8 %.

抄録全体を表示

The authors claim that to represent the knowledge for planning is necessary to implement a computer aided planning system for structural design. The authors regard the planning process as the process of selecting action that modifies the sate of affairs to the desirable state for the designer, and intend to propose a representation schema of the planning knowledge use in structural design. The proposed schema is composed of deduction based on theoretical knowledge, heuristics, abduction based on theoretical knowledge and practical reasoning employing knowledge about action. With the proposed schema, examples of the structural design planning for the seismic retrofit is represented formally. The authors may conclude that the schema is valid for representing planning knowledge on structural design.

抄録全体を表示

In this paper, three items of discussed in the present paper are as follows ; 1. Why did the authors assume 2/Lx, 2/Ly on Matrix [A] ? 2. Why did the authors assume that the shape of yield surface is a octagon ? 3. On the computing in the present paper, the authors use Prager's hardening rule and Ziegler's hardening rule. Each computiong data have different physical characteristics. Why did the authors compare with both computing data?

抄録全体を表示

The authors answer Mr. H. Uehara's questions as follows. The number of the answer corresponds to that of the question. 1. The authors used 2/Lx and 2/Ly as components of transformation matrix [A], because those components made a series of formulations simple. 2. The authors did not assume the shape of the yield,surface. The shape of the yield surface necessarily depended on the structural model, and was an octahedron. 3. It is a matter of course that different assumptions cause different physical characteristics. The authors compared the two rules to make clear the difference.

抄録全体を表示