Fly ash have an effect on controlling expansion due to Alkali-aggregate reaction(AAR). However, the effect varies in types of fly ash. In this paper, an evaluation method of the effect of fly ash on controlling expansion of concrete due to AAR is proposed using Na_2O equivalent value. And evaluation methods of the reactivy of fly ash in alkali are also proposed, that is a chemical method and an electrical conductivity method. Relationship between reactivity of fly ash and its effect on controlling expansion of concrete due to AAR are investigated. It becomes clear that these two factors are correlated.

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This paper proposes and describes a new test method for ductile cementitious composite materials to evaluate the basic material stress-strain properties under tension, compression, and tension-compression reversed cyclic loading conditions. Those properties are indispensable for identification of materials and for evaluating the performance of structural elements utilizing ductile cementitious composite materials. Required condition for the test method, some problems in the conventional tension tests, details of the development for the test method, and verification of the test results in comparison with those of the conventional standard test methods for tension and compression of concrete are presented.

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High performance short fiber reinforced cementitious composites, named as engineered cementitious composites (ECC), have been realized with reaching several percent of tensile strain capacity. The ultimate purpose of this study is to establish material design scheme for ECC, and this establishment necessitates to predict first cracking strength. This study proposed micromechanics-based prediction theory for first cracking strength, which takes into account: 1) fiber rupture during bridging action on a crack plane, and 2) chemical bond in interface between fiber and matrix. This theory was substantiated in comparison with tensile test data of ECC. In addition, analysis with this theory revealed that first cracking strength can be controlled via maximum fiber bridging stress, which is analytically expressed as a function of constitutive parameters of ECC such as bond strength. As a result, one can design ECC so as to have first cracking strength more than requirement using the proposed theory.

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In this paper, the creep behavior and the restrained deformation property for early age concrete were investigated by the rheological analysis method based on the burgers model for a non-linear function and the iterative analysis method based on the creep superposition. According to the analysis, the following results were clarified: 1) The creep behavior in early age could be considered by the rheological coefficient model on a time dependence for early age concrete. 2) The restrained deformation analysis method based on creep solution by the rheological coefficient model was proporsed. 3) The rheological analysis method based on the burgers model for a non-linear function was effective for early age concrete.

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The outline of this study is as follows ; The first, sensory tests were carried out to make psychological scales of slipperiness, hardness, stability of footing and suitability for walking of "Loose-Surface". Then it was cleared that psychological scales did not correspond to the physical values for "Fixed-Surface" detected by apparatus developed by author in former researches. The second, it was investigated that psychological scales corresponded to displacements of "Loose-Surface" detected by apparatus presented in former report. Finally, the relative evaluation method of suitability for walking of "Loose-Surface" was presented based on the relationship of psychological scales and physical values.

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This study was carried out to establish a method for estimating snow load under control of condition for snow sliding on roofs. In order to investigate snow load on pitched roofs, we observed snow on some constructions located in Hokkaido. What we concluded through the investigation are as follows: 1) Snow sliding occurs on the condition that the ambient temperature is above 0℃ in which adfreezing resistance never happens. 2) Duration time which makes snow sliding possible depends mainly on snow load on the above condition. 3) Under the condition of being snow on the roof, snow density is in proportion to the days the snow stays there. Consequently, load can be estimated by the equation below: p=2.22t+160(p : snow density, t: days ofcontinuous snow cover)

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The estimation of near-field ground motion intensity is an important subject in earthquake engineering. However, the characteristics of nearfield ground motion are not well known because of the limited amount of recorded data from the epicentral regions. Some post-earthquake investigation reports have pointed out that the upthrow of boulders in the epicentral region might be evidence of extremely strong ground motions. In this paper, the upthrow phenomenon is interpreted through numerical simulations and shaking-table experiments, and a method of estimating ground-motion intensity from boulder upthrow phenomenon is proposed. The conclusions reached on the basis of the results of our studies are as follows: (a) The upthrow phenomenon is mainly the result of the large-velocity amplitude of ground motions at the soil surface. (b) Boulder upthrow is caused by periodic motion rather than impulsive motion. (c) An equation by which the maximum velocity of ground motion is estimated from the horizontal displacement of a boulder has been proposed based on numerical simulations assuming the ground motion to be a sine wave. The proposed formula shows good correspondence with the results of our shaking-table experiments.

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An active identification scheme is presented to improve the accuracy in the health monitoring of multistory buildings. A series of shaking table and vibration generator tests are performed using a five story experimental model with eccentricity. The location and extent of damage are estimated by inverse perturbation method using the change in modal properties identified by ARMA model. Higher modes are excited by harmonic excitation in the structure, whereas lower modes are excited by white noise excitation at the base. Translational modes are used to evaluate the change in story stiffness in the vertical damage searching, whereas torsional modes are used to evaluate the change in frame stiffness in the horizontal damage searching. Based on the damage identification results using experimental data, the effectiveness and limitation of the proposed scheme is investigated.

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This paper proposes a response spectrum method (RSM) for evaluating nonlinear amplification of surface strata (SS) overlying an engineering bedrock (EBR). The proposed RSM follows the procedures below. (1) Represent the response characteristics of SS on EBR by a multi-lumped mass model with shear springs and damping coefficients. (2) Calculate a period T_1, a mode shape U and a modal damping factor ζ_1 for the first vibration mode. (3) Evaluate the equivalent shear wave velocity Vs_e of SS. (4) Evaluate the amplification factor G_5 of the surface to EBR at T_1 using the Haskell matrix of two strata consisting of an equivalent SS with Vs_e and ζ_1 on EBR. (5) Evaluate the displacements and shear strains in SS. (6) In accordance with nonlinear relations between shear modulus (G), damping factors (h) and shear strains, replace soil constants G and h by those corresponding to strains. (7) Return to step (1) with revised G and h. Iterate these procedures until T_1 becomes stable. (8) After T_1 is converged, calculate the response distributions in SS. The applicability of the proposed RSM is confirmed through the comparative studies.

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Since earthquake ground motions are uncertain even with the present knowledge available, it is difficult to predict forthcoming events in a reasonable way. ft is therefore desirable to develop a robust structural design method taking into account these uncertainties. Critical excitation approaches are promising to overcome such difficulties. In this paper, the power (area of power spectral density function) and the intensity (magnitude of power spectral density function) are fixed and the critical excitation is found under these restrictions. A design problem for restricted variable design earthquakes is formulated as a min-max problem which is expected to lead to the maximum global performance design for variable critical excitations.

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This paper presents an easy modeling of a framed structure suitable to calculate its load-carrying capacity considering interacted bending and axial resistances. An efficient linear-programming technique proposed by Livesley, termed Compact Procedure, is applied to a 2D or 3D frame model including multi-spring joints, where a plastic hinge is replaced by a set of rigid-plastic uni-axial springs, where it is not required to recognize the whole interaction surface of resistances at a plastic portion. A few shapes of interaction surfaces are also presented for users' conveniences: a square hollow section and a H-shaped section are approximated by a simple 8-spring layout, respectively, and their 3D interaction surfaces are solved by an exhaustive enumeration method based on the convex set theory. The results agree fairly well with the existing design formulas for interacted bi-axial bending and axial resistances.

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Strength of carbon fiber chip reinforced concrete cylindrical shells was investigated on following 3 aspects. l. Strength and cracking patterns of carbon fiber chip reinforced concrete shells with three kinds of edge members were analyzed by both the failure experiment and the nonlinear numerical analyses. 2. Effect of openings within carbon fiber chip reinforced concrete shells on strength was described, both experimentally and theoretically, in comparison with those of standard steel reinforced concrete shells. 3. Nonlinear behavior of carbon fiber chip reinforced concrete shells under point load was shown.

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Evolutionary Structural Optimization (ESO) method is one of the most powerful and promising technique for pursuing the optimal structural form among the other methods as the homogenization design technique and the bubble method. Although it is easy to carry out the calculation of ESO, there have been remained some weak points in its evolutionary process, by which inefficiency of calculation is caused or unreasonable solutions are concluded. A new method through the usage of the contour lines is proposed in order to remove such defects of the usual ESO as well as to enable the structures to not only be scraped off but also grow up toward the final optimal structures. Some numerical examples clearly show the effectiveness of the proposed scheme.

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Reinforced concrete floor slabs need to be designed with ensured structural serviceability against their long-term deflection. Its governing factors include slab edge restraining condition, slab types (both sectionally solid and hollowed),concrete properties, the long-term deflection multiplier etc. In view of this, equations are proposed to calculate the minimum thickness of the slab, taking account of such factors while conditional on its exemption from prescribed excessive long-term deflections. In an initial design stage our above means easily enables a moderate evaluation of minimum slab thickness without its overestimation which often arises from the AIJ Design Code formula esp. for a floor slab of about 6m or a greater span.

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The Adhered Steel Brace is one effective retrofitting method of the earthquake-resistance strengthening work that can be done with little noise and little vibration. In this method, the steel frame with brace is bonded to the existing columns and beams by epoxy resin. The work also can be done in a shorter period of time. The seismic behavior of the adhered steel brace was investigated. The seven specimens were tested under constant compressive loads and repeated lateral forces. The main parameters are the adhesion area and shapes of braces. We compared the adhered braces with the conventional bracing method and the brace using mortar to the replacement of epoxy resin. We discussed the sliding strength of joints between the existing frame and epoxy resin, the mechanism after sliding of joints and the ultimate lateral strength.

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This is an experimental study to understand two-dimensional restoring force characteristics of R/C columns under varying axial force based on consideration of analogy to the theory of plasticity. Four identical specimens were subjected to cyclic lateral load and varying axial force. Based on the test results, analogy to the theory of plasticity, and evaluation of rigidity degradation are studied. As the test results, when deformation increment vectors lie in the direction of loading on the condition that the columns yield, it can be said that plastic deformation increments calculated by experimental data and the plastic theory agree with the flow rule in direction. Elastic rigidity degrading ratio calculated by using the theory of plasticity and experimental data as numerical results agree with test result increases gradually during loading stage as stress decreases along the yield surface. On the other hand, when deformation increment vectors turn to the direction of unloading, stress increment vectors are widely different from vectors of elastic assumption. Rigidity degradation ratio on unloading stage of the column subjected to cyclic lateral loading under constant axial force decreases as cycles are repeated and lateral deformation increase, and shows tendency to be constant as more cycles are repeated.

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In the earthquake resistant design of high-rise reinforced concrete(R/C) buildings, it is very important to clarify the inelastic behaviour of columns subjected to bending moment and axial force. Among the various analytical models for R/C column, the plasticity theorem model is considered to have a lot of advantage to 3-dimensional inelastic analysis. We have been developing an analytical method based on the plasticity theorem. In this paper, we performed static analyses of R/C columns under bending moment and varying axial force, and a dynamic analysis of shaking table test of a 3-story R/C space frame using this method. Through these analyses, the usefulness of this method based on the plasticity theorem to 3-dimensional inelastic analysis of R/C columns subjected to bending moment and axial force is shown.

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RC structures used the recycled aggregate concrete composed of recycled aggregate will evidently become concrete waste in due time. Such concrete waste has to be recycled as well in order to reduce concrete waste. In other words, the ideal goal is to use the recycled aggregate continuously. This paper investigated from two types of experiments (experiment I and II) that the recycled aggregate concrete composed of repeatedly recycled aggregate is able to use as a appropriate material for aseismatic performance of RC frame. In experiment I, the influence of the recycling frequency on the properties of recycled coarse aggregate was evaluated. This experiment showed that recycled coarse aggregate changes to mortar after being recycled many times. Experiment 11 used RC beam specimens made of recycled aggregate concrete itself composed of coarse aggregate made from mortar, which represented the condition of repeatedly recycled coarse aggregate. Such specimens were tested on the flexural, shear, and bond failure and it was investigated that the repeatedly recycled aggregate concrete could be used for aseismatic performance of RC frames.

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This paper presents the structural characteristics and effect of the deformation control of high-rise building composed by super-structure frame. Analytical studies are as follows. In A series, the section of the column, beam, brace, and, super-beam were separately changed. In S series, the numbers of super-beam were changed. In F series, all of the numbers of the frame were changed equally. Finally, it is clarified that the super-structure frame style is very effective to control the deformation of the high-rise building and is most effective to change the section of the super-beam in the deformation control.

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This paper deals with equivalent single-degree-of-freedom systems that can simulate the seismic response of fishbone-shaped frames. The response of a multi-story frame subjected to an earthquake is strongly affected by the collapse mechanism that forms in the frame. In this paper, a method for predicting the collapse mechanism under earthquake excitations is devised, taking into consideration the correlations between dynamic horizontal forces acting on each story. In addition, load-deformation relationships of equivalent single-degree-of-freedom systems are determined based on the collapse mechanism. A good correlation is achieved between the results calculated by the equivalent single-degree-of-freedom systems and the seismic response of fishbone-shaped frames.

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This paper presents a seismic design procedure to estimate the residual deformation of steel frames with hysteretic dampers when main frames do not yield under earthquake excitations. Dynamic response analysis is carried out on single-degree-of-freedom systems with various structural parameters. From these numerical results, the critical parameters that control residual deformation are found to be (1) stiffness ratio of damper system to main frame and (2) initial yield deformation. Based upon the energy-balance consideration during a half-cycle, residual deformation is derived in explicit form as functions of these parameters. The proposed method is applicable for multistory frames.

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Theoretical studies are presented on the prediction of bending strength of a composite beam-column subjected to bi-axial bending. The main objective of this study is to refine the AIJ design formula which is based on the modified-superposed strength method. Sophisticated moment magnification factor is introduced, which can be applied to long columns subjected to non-symmetric bi-axial bending. Bending strength of a long column is calculated as the full plastic moment, which is obtained by the generalized-superposed strength method, divided by the moment magnification factor. Proposed formula shows a good agreement with precise numerical solutions.

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As a part of the U.S.-Japan Cooperative Earthquake Engineering Research Program on Composite and Hybrid Structures, ten concrete filled steel tubular column (CFT) to structural steel beam connections were tested under reversed cyclic loading to investigate the effects of high material strength, configuration and geometry of connections, column axial load and loading direction on the shear strengths and deformation capacity. This paper presents the test results and discusses the shear behavior of CFT connections. All the specimens reached their ultimate panel shear strengths at least to be 1.3 times of the design panel ultimate strengths by AIJ-SRC (1987) formula, whose scope of application is for medium to low material strengths and not for high material strengths tested in this study. This means that the current AIJ-SRC formula can be conservatively used for high material strengths. The deformation capacity of the connections was also verified to have enough ductility.

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This paper deals with some investigations of the actual situation and fire protection management for shrines and temples in Taito Ward of Tokyo. The results of the investigations show that 52.4% of these facilities are built of wooden structure. In Yanaka area, there are many wooden temples with large precincts, and fire vehicles cannot approach the fire buildings in this area because of narrow alleys. In Nishi-Asakusa area, the rate of fire resistant buildings with small precincts is high. Owners of wooden buildings are anxious about arson and fire spread, however fire protection devices such a sprinkler and a drencher are rarely installed.

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