To estimate strength of concrete in structures non-destructive testing of ultra-sonic, rebound and combined methods are used in this study. From experimental study using full scale model walls regression equations to estimate strength of concrete by these testing methods and allowance of estimations are presented respectively. From field investigations for actual buildings aged 20〜50 years, average value and variation of strength of concrete in structures can be estimated with reasonable accuracy by using regression equations mentioned above and correcting factors as to longer age of concrete obtained from the study. And from statistical study, the numbers of measurements of non-destructive test to estimate strength of concrete required to maintain equivalent accuracy in comparing with the conventional destructive test are proposed.

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Four types of clear coating systems which include a newly developed system were evaluated through sunshine carbon arcs irradiation, outdoor exposure, and exposure at elevated temperature. Color difference, residual gloss, and specific reflection spectra within visible layer were measured during these aging tests. Cross-cut test and SEM observation were also carried out for some specimens. The new clear coating system utilizes a new type of fluoropolymer and polyethylene-glycol methacrylate solution as a top coating material and a primer, respectively. The new system shows higher performance than an existina oolvurethane coatina svstem in everv test item.

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Annual extreme winds due to typhoons for 40 years from 1950 are investigated at 28 weather stations in the western Japan which belong to a typhoon-prone region. The predictions for the return period of 500 years are larger about 10%, in average, than those based on usual annual maximum wind speeds owing to the randamness of typhoons. Three subsets of 20 year records from 40 years are also investigated. In most cases the last subset underestimates excessively. It may be caused by the alteration from 3-cup anemometers to propeller ones.

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A foundation work for reduction of earthquake response was proposed in a previous paper (Part I ). The dynamic deformation characteristics of a high damping material employed in this foundation work are shown in this paper (Part II). A mixture material of gravel and asphalt termed Asphalt Gravel was selected for the high damping material on which the dynamic deformation tests were conducted. The test results indicated that the elastic moduli changed with fluctuation of temperature, confining stress and exciting frequency, but this material still provided higher damping capacity and exhibited a stable hysteresis loop. No inadequate points were recognized on application of the asphalt gravel to this foundation work.

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This paper presents distribution of structural damage or indoor damage of houses (including overturning of furniture, scattering in the room and so on) in the city area as to earthquake damage of the 1993 Kushiro-oki Earthquake. The estimation method which has been developed for structural or indoor damage was also adopted into the damage in Kushiro City. Structural damage occurred on the diluvial plateau and there was few damage on the alluvial soil. On the other hand, indoor damage occurred severely in some area and its distribution characteristics was very complicated. Distribution of structural and indoor damage were strongly affected by the dynamic characteristics of surface soil with the exception of the damage by soil failure. General tendency of the damage distribution was reappeared by this method, however.

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In carrying out a research on local site effect of earthquake wave propagation, it is necessary to predict base motions from the observed surface motions. The characteristic method is known to be applicable to linear wave propagation problems as well as to nonlinear. However, little research work has been conducted on this method, even though it can be used to predict base motions by adopting a time domain nonlinear hysteretic effect. The filtering method is also useful in solving the problems. The computer program "SHAKE" is well-known. This method has been verified by several correlation analyses. However, it gives unacceptable amplification in high frequency range because frequency independent damping factor is evaluated only by the effective strain and employed in this method. This paper describes the characteristics method for nonlinear base motion analysis, and investigates its capablity and applicability to the inversion technique.

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The subject of designing earth retaining structures is how to estimate the appropriate design load. Usually design load is determined by a rule based on measurements of lateral pressure for the retained side, and by theoretical analysis for the excavated side. This paper suggests a method to determine the design load through the consideration based on measurement results of both sides.

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The main aim of this paper is to present several "elastic buckling loads" of uniformly pressurized perfect and imperfect spherical caps in relation to slenderness parameters. "Elastic buckling loads", in this paper, mean R. S.(Reduced Stiffness ) load, asymmetric bifurcation load, upper buckling load with and without initial imperfections, Astatic buckling load and so on. Through parametric studies, the buckling characteristics are also illustrated. Numerical results are normalized and plotted against three slenderness parameters derived from : classical buckling stress; linear buckling stress; and equivalent stress, respectively. A comparison is made, in view of buckling stresses, with the values given by buckling strength curves in the codes and with past experimental results.

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The story shear distribution of a high-rise reinforced concrete building is investigated for the earthquake resistant design. The time-invariable oscillatory mode shapes of the building designed with the appropriate story shear strength distribution are close to the elastic stiffness mode shapes. This means the seismic coefficient distribution obtained by the SRSS method using the elastic mode shapes is reasonable. The seismic coefficient distribution shapes proposed previously are compared with this distribution shape. The results of response analyses show if the seismic coefficient distribution with disregard to higher mode effect is used for design, it leads to the drift concentration. The story shear strength should be within 1.2 times of the design shear force distribution to avoid the drift concentration caused by the discontinuous distribution.

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It is important that composite slabs behave as one element in precast concrete and cast-in-place concrete. To investigate the shearing strength and behavior of shearing force transfer of diamond shaped rough surface at the interface, double shearing tests were carried out. As the results of tests, it has been found that the diamond shaped rough surface was effective to behave as composite slabs. Finally authors propose allowable shearing strength at the interface of composite slabs.

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Seismic loads for high rise buildings are affected by higher modes even base shear force. This paper investigates the base shear coefficient for the preliminary earthquake resistant design considering the second mode contribution using a simple model and the design earthquake acceleration response spectrum. The required design base shear strength is established from this spectrum and the design criteria such as story drift limitation and allowable ductility factors of structural members. Final suggestion of this paper is C_B=0.24/Ti, where C_B is base shear coefficient and Ti is initial period of a building. The dynamic response analysis for the buildings having the base shear strength calculated by this equation showed sufficient earthquake resistant ability.

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To save labor for form work and installation of reinforcement at construction site and to save wood resources, square shell concrete form (PCa-shell) was developed. The PCa-shell is made of high strength concrete (Fc=500 kgf/cm^2) and contains hoops and tie bars. A column is made by putting the PCa-shell on main bars and then molding core concrete in it. So main bars of the column do not touch directly with lateral reinforcements. In this paper, the shear-flexural structural experiments on cast-in-place reinforced concrete members using the PCa-shell (half-precast members) were described. It appeared that the structural performances of these half-precast members were not less than usual reinforced concrete members. And the equations of flexural, shear and bond-split ultimate strength of the half-precast members were proposed

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Brittle fracture in large steel structures subjected to high stress reversals is triggered by fibrous cracks initiated at stress concentration spots such as toes of weld. In this study the effect of specimen size on the critical strain at the onset of fibrous crack is investigated. The test was performed under quasi-static tensile load applied on round bar specimens of SM 490 steel having a circumferential notch at the center. Three different diameters of bars and six different shapes of notches were examined in order to investigate their influences. Major findings are : (1) No apparent correlation is observed between fibrous crack initiation strain and specimen size ; and (2) The fibrous crack initiation strain tends to slightly decrease with notch sharpness but is approximately equal to the stability limit strain sustaining the maximum load.

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The maximum bending capacity and the plastic deformation capacity of cantilever beam-columns with H-sections made of various grades of steel are investigated. Dimensions of sections are so selected that the maximum bending strengths are governed by the local buckling of plate elements. Reasonable correlations are found between experimental results and theoretical predictions. Finally .width-to-thickness ratio limitations of flange and web corresponding to any ductility demand for each grade of steel are presented.

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The purpose of this paper is to clarify the strength characteristics of circular tubes with outer constraints by stub column tests and numerical analysis. The circular tube is constrained by another circular tube outside. It is noted that the outer constraint are effective as the short clearance between the circular tubes. In this paper an analytical method for geometrically and materially nonlinear contact problems of thin continua is applied. The penalty method is used for the estimation of the contact. It is shown that the results obtained by this analysis well explain the experimental test data.

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This paper discusses the strength of a new SRC column. The SRC column is small size steel encased reinforced concrete column using high strength concrete and high strength hoop reinforcements. This SRC column is developed in order to have much higher shear strength than that of a reinforced concrete column. Seven SRC column specimens were made and tested. The concrete section of the specimen was 20cm×20cm, the steel section 10cm×5cm×0.5cm×0.7cm. Each specimen was diagonally compressed and consequently subjected to axial force, bending moment and shearing force. Experimental results indicate that high strength concrete and high strength hoop reinforcements function effectively. In this SRC column, it is negligible that the concrete section is separated by the steel.

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A third-order upwind finite element scheme for direct numerical simulation of high Reynolds number flows is presented. The scheme is proposed based on both the Petrov-Galerkin formulation and the mixed method which enables to use the linear elements. Numerical dissipation added into the scheme is expressed by the fourth-differentials with respect to the flow velocities, so that accuracy of the discretization for the advection therms becomes a third-order. Numerical results of flows in a cavity are presented to illustrate the effectiveness and robustness of the proposed upwind scheme.

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The thermal elongation of steel beams should be taken into account for fire-resistant design of concrete-filled steel tube (C.F.T.) columns in case of fire. Five C.F.T. column specimens using rectangular steel tubes and four C.F.T. column specimens using circular steel tubes were heated under constant axial load and deformation to simulate the elongation. The tests results are summarized as follows: 1) The fire resistance was 2 hours for rectangular specimens and 1 hour for circular specimens, when the axial load ratio was equal to 0.45 and the displacement angle was equal to 1/100. 2) All C.F.T. columns were axially elongated most at early stage, and then shrinked gradually to failure. 3) After 30 minute heating, the C.F.T. columns could not resist the bending moment due to the elongation of beams, however the columns could sustain the axial load.

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This report proposes a reasoning system by neural network for average building weight that is needed for assuming member sections in structural planning, by using simple information such as structural material types and shapes. 6 input parameters are used on the basis of the first author's structural design experiences. The training and verification data are used from the works that were really designed or planned in FUJITA CORPORATION. From the result of the verification, this system is proved to be sufficient and effective in structural planning, though the data has to be carefully selected.

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This paper describes an optimal adaptive and predictive control system and its digital simulations for a single-degree-of-freedom system subjected to earthquake loading. In this system, an active mass driver system and an equivalent variable mass system are employed as an active control method. Prediction of earthquake input and structural identification are performed by using multi-layered neural networks based on the error back-propagation method. Off-line training are performed for these neural networks, and future earthquake inputs and structural responses of a structure are predicted Optimization is performed by means of maximizing decision. In maximizing decision, optimal target control variables are determined by using assumed membership functions of target responses. In this system, a certain interval is introduced as a control interval. Prediction of earthquake inputs and structural responses and the maximizing decision are performed with respect to the maximum values in every control interval. Results of digital simulations show the effectiveness of the proposed control system.

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Dr. Katsura studied characteristics of pressure on a lodel building due to gust, and then, he discussed wind tunnel testing method. In his analyses of pressure, he introduced a few unfamiliar concepts. Not only his concepts but also the phenomenon to be understood, the following points are discussed and questions are raised; 1)why was the pressure due to a particular type of gust examined ? 2)shoudn't the scale of gust be defined more exactly? 3)was the study confined to the pressure which was not much influenced by separation? 4)does Eq.(4) hold true for any kind of gust or for the pressure which is influenced by separation?

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The following itemized sentences are replies to the questionnaires in Dr. Matsumotos1 discussion respectively. 1) A gust with a large scale is the most suitable stream field in natural turbulent winds for analyzing non-stationary problems. 2) It seems to be impossible to define more exactly the scales for many kinds of gusts. 3) The fundamental concept is not confined to a low-rise building in spite of dealing with it. 4) The kernel model expressed by the equation (4) is regarding only a principal flow pattern produced by a stream with nearly straight path.

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