This paper attempts to study the characteristics of long-period (2 to 20 sec) ground motions during the 1983 Nihonkai-chubu earthquake from the direct information of low-magnification seismograph records obtained at 26 observation sites of the Japan Meteorological Agency (JMA). The major conclusions obtained in this study may be summarized as follows ; 1) The deep subsurface ground structure is accurately estimated by using the travel curves of initial motions of the P-and S-waves obtained by JMA's seismograms. 2) A simple method used for estimation of maximum ground displacement is proposed after the discussion on influence of correction filter of JMA's seismograph on peak value and predominant period of the seismogram. 3) The variation of the arm length, whose effect is not considered in standard data processing, affects considerably peak ground motions. Because the mechanical arm length is not accurately known in the case of the records by the old type seismographs, the procedure of the estimation of arm length must be established. 4) The properties in th$ period range of 2 to 7 sec of the displacement records were found to be in reasonable agreement with the corresponding properties predicted by Japanese empirical relation obtained from statistical analysis on acceleration strong-motion records. 5) The velocity response spectra calculated from the displacement seismograms are compared with the design spectra given for large-scale structures such as high-rise buildings, long-span suspension bridges and large oil storage tanks. As the velocity response spectra exceed the design spectra under certain circumstances, the limit value provided by the current design practice should be increased for some sites (for example, Niigata) due to local seismic-wave amplifications.

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This paper proposed load displacement relationship models for reinforced concrete shear walls of nuclear reactor buildings based on the results obtained from load tests using reduced scale model tests. Establishing a feasible earthquake-resistant design to withstand large earthquake is very important, especially in Japan. It is necessary, therefore, to determine the elastic and plastic range characteristics of reactor buildings. The relationships between lateral load and lateral displacement are idealized with loops and envelope curves which envelope apises of loops. Lateral displacement consists of shear and flexural displacement. In the case of reduced scale models, flexural displacement consists of rotational displacement at the base. Shear displacement is obtained from the relationship between shear stress r and shear strain γ, the flexural displacement from the relationship between moment M and curvature φ and the rotational displacement from the relationship between base moment M_B and rotational angle φ using the beam theory. Equations for calculating the τ〜γ envelope curves were proposed in Part 1, based on 34 reduced model tests and 18 numerical tests. After careful consideration of 33 reduced model tests in which shear and flexural displacement were measured, equations for caluculating M〜φ and M_B〜φ envelope curves were proposed. The computed envelope curves showed good agreement with experiments. Finally, experimental load displacement envelope curves were compared with calculated ones which were computed by the τ〜γ, M〜φ and M_B〜φ relationships. The computed envelope curves adequately trace 52 tests results.

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The plastic deformation capacities of square and circular hollow section steel members subject to bending or combined bending and compression are analysed on the bases of maximum-to-yield stress ratio of stub-column. The maximum-to-yield stress ratio was evaluated statistically using a large number of test results on stubcolumns. The theoretical predictions thus obtained are compared with available experimental results on member deformabilities, and found a good correlation each other. The width-to-thickness ratios predicted from this research according to the specified ductility demands are compared with the width-to-thickness limitations prescribed in the current specifications. It is pointed out that the width-to-thickness limitations for cold formed square, and circular hollow section members should be more severe than the current regulations.

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Plasticity in steel is characterized by an appreciable amount of plastic flow which precedes strain-hardening. This study deals with an evaluation of the out of plane flexural rigidities and the modulus in shear of yielded steel plates at the instance of plate buckling under shear force. Assuming that the stress-strain response of steel in this range follows the incremental plasticity theory for nonhardening material together with von Mises' yield criterion, an explicit formulation is derived for the moduli to relate the flexural rigidities and the modulus in shear of steel plate. Comparison is made of the magnitude of so derived moduli with those in the strain-hardening range. In both range of plastic flow and strain-hardening, flexural rigidities have the same values with those in the elastic range. However modulus in shear in the plastic flow range differs from that in the strain-hardening range. And in the former range, its value equals to zero. Buckling of steel plate with its four edges simply supported under shear force is examined by the moduli derived from the viewpoints of buckling stress and strain. As the difference of the results between the plastic flow and strain-hardening range is small and they can be regarded as the same, analysis is performed by the moduli in the plastic flow range.

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A portable measurement system for ambient vibration test of building has been developed. The motive of the development is to know the gereral trends of vibration characteristics of many actual buidings. The equipment of the system consists of transducers, amplifiers, A/D converter and handheld micro-computer. The advantages of the system are high portability, quick setting of the equipment, and immediate analysis of the records at the field, without any work in laboratory. The analysis gives the natural periods and damping coefficients for translational and torsional vibrations. The weight of the equipment for low-rise buiding is only 9 kg and that for highrise building is 20 kg. They are capable of operating by only dry battery. The vibration characteristics of buildings in Tokyo, Yokohama and Mexico City were measured by this system. The results show large difference on rigidity of buildings in Japan and Mexico.

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In general, air-supported structures are designed primarily against wind load or snow load which causes the greatest stresses or the large defrections in the enviromental condition. Due to the high flexibility of an air-supported structure, its equiliblium shape and the associated external loading are greatly influenced by the interactions between the structure and the load. In this paper, we describe an experimental research on the structural characteristics of low-profile cablereinforced air-supported structure by using a large-scale model (span 25m). Particularly, 1) experimental results by the uniform load (internal pressure), 2) experimental results in the statical wind load distribution and dynamical behavior of roof defrections, cable-end forces and internal pressure measured in a typhoon, 3) experimental results under some patterns of snow distribution are mentioned.

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The load-deformation responses of the slender reinforced concrete columns under biaxially eccentric loads are solved by the numerical method of a second-order analysis, taking into account the effects of deflections and changes in stiffness of the columns on moments and forces. The column length is divided into several segments of the same length. For the equilibrium differential equation, the application of the numerical integration process of the Runge-Kutta-Gill method and the Newton-Raphson iteration technique yields the deflections corresponding to the given load, step by step. The test results given in the previously reported paper, Part 1, are compared with the numerical solutions of the analysis. The following conclusions can be drawn for the ultimate load and the deformation behavior of the slender reinforced concrete columns with square cross section. (1) The ultimate load carrying capacity of a slender column is reduced by the additional eccentricity due to lateral deflections, even in a column having a length to depth ratio of 15. (2) The numerical analysis to solve the load-deformation response of the column predicts very well the test behavior. (3) In the case of square long columns with evenly distributed reinforcement, it is remarkable that there is not much difference on ultimate loads of the columns in spite of variation of the angles of loading point. (4) The direction of deflection of the column under biaxially eccentric loads corresponds closely to the plane including the loading points and the centroids of the end section, before reaching the maximum load. However, after the attainment of the maximum load, the column has a tendency to deflect away from that plane.

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This report is experimental research on the full size Nuki-structure under the lateral forces. These models are composed with a glued laminated timber beam and a glued laminated timbercolumn or a built-up glueded square-log column.

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This report presents an experimental method for predicting instant, transient and creep settlement of direct foundations on Kanto Loam. The applicability of this method was also examined by comparing actual and predicted foundation settlements. Special attention should be given to the following Conclusions. (1) Instant settlement can be predicted using elastic theory when Young's elastic modulus, E is assumed equal to 145 qu. (2) The relation between transient settlement, S_<EC>, and time, t, is a straigth line on the S_<EC>-log t plane, with the settlement rate being in inverse proportion to E. The same has also been observed in regard to the behavior of creep settlement, S_c, time in logarithm, log t, and E. (3) As a general rule '. total settlement of an ordinary continuous footing on Kanto Loam is about 0. 36 cm to 2. 72 cm over a period of 10 years, while creep settlement is in the range of 30 to 60% of the total settlement and averages 50%. Transient settlement included in the total settlement is negligible.

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In this report, a macro model was proposed to predict the ultimate strength of shear walls in the limited case, where the yield of the longitudinal reinforcement in tension column and of the vertical reinforcement in wall was accompanied by. It was disclosed that the ultimate strength of shear walls after flexural yielding could be well estimated by this macro model. Also, an equation was obtained by this macro model to estimate the horizontal reinforcement ratio which the ultimate strength did not increase on and after in spite of the increase of horizontal reinforcement. In addition, the ductility of shear walls after flexural yielding could be roughly estimated by using the calculation results of this macro model as parameter.

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