In this paper, the effects of heterogeneity of structural concrete on the mechanical behaviors of reinforced concrete (RC) members are discussed. Main results are summarized as follows : 1) The unstable curvature localization in RC beam caused by heterogeneity of structural concrete is relatively small when the perfect bond between longitudinal steel bar and concrete is assumed, but is cleary noticed when the slippage between longitudinal steel bar and concrete is considered. 2) The maximum load and ductility of RC member subjected to multiaxial loading in combination with axial force and bending moment decrease with the increase of coefficient of variation of concrete strength. 3) The effect of heterogeneity of structural concrete on mechanical properties of RC column depends on the loading method. Using the loading method that the rotations of both ends of RC column are confined, the load deflection curve and curvature distribution of RC column are hardly affected by the distribution of concrete strength, owing to the casting height. Using the loading method that the distribution of bending moment is reversly symmetrical with respect to the center of RC column, however, the mechanical properties of RC column is very affected by heterogeneity of structural concrete.

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The purpose of this study is to investigate the behavior of steel structures subjected to a strong earthquake and to evaluate the damage from a microscopic point of view. For this purpose, the authors have adopted two kinds of research techniques. The first is the "ON-LINE EARTHQUAKE RESPONSE SIMULATION SYSTEM (ON-LINE SIMULATION SYSTEM)", which is composed of an electro-hydrauric testing machine controled by a computer and a full scale specimen. Since a term of restoring force in the equation of motion is to be substituted by the actual reaction of a specimen under test, we can obtain the non-linear response of structure without any assumption about the hysteretic characteristics. Based on this method, the dynamic behavior of simple steel structures subjected to an intense earthquakes were simulated. The second technique is the "X-RAY DIFFRACTION METHOD". Although this method is usually regarded an experimental technique particular to the material science, we have realized the good applicability for the study of structural engineering, Because X-ray diffraction method is advantageous in investigating the microscopic behavior of steel member such as the plastic deformation and the low cycle fatigue. From the view point stated above, we have adopted this method for the evaluation of low cycle fatigue damage of steel member subjected to an earthquake. The experiment has been performed by radiating the X-ray at several stages of the ON-LINE SIMULATION. As has been expected, the X-ray diffraction patterns have changed in a regular manner depending on the degree of fatigue damge, and the results have shown a good possibility that the X-ray diffraction approach can offer a powerful tool for the detection of the earthquake damage of steel members.

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This paper describs aseismic design philosophy of buildings with maldistributed shear wall which causes the eccentricity in strength as well as in stiffness, based on energy absorption concepts obtained from inelastic torsional response analyses during sevre earthquake. Through this study, the following conclusions are derived. 1) Total plastic strain energy stored in an eccentric building is, without reference to the value of eccentricity, much the same with energy stored in a building without shear wall and non-eccentricity. 2) Torsionl response behavior of a building subjected too lateral ground motions under a condition of simultaneous imputs with two orthogonal directions can be estimated almost the same as the sum of two torsional responses where the motions are independently applied. 3) Effect of torsion. depends significantly on C_m value which is defined as a ratio of resistant moment in unforced direction to torsional moment in forced direction, where either moment is a function of frame stregth. Torsional deformation excels extremely in the range of C_m≤1, while the torsional effect can be ignored in C_m≤5. 4) Maximum ductility demand in the range of C_m≤1, _xμ_2, is calculated by use of ductility demand in the non-eccentric building, _xμ_0, as shown in eq.(14). A value of _xμ_2/_xμ_0 highly depends on a value of λ, which is a ratio of side length of orthogonal to parallel against the horizontal force direction. When the value of λ exceeds one, _xμ_2/_xμ_0 becomes greater than one in general.

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In order to connect steel columns with reinforced concrete footing beams rigidly, the column-to-footing connections where the steel column bases are clad with reinforced concrete stubs are often used in Japan. In this paper, the mechanism of stress transfer of this type of connections, and, the initiation strength of shear cracking and the ultimate shear strength of the cladding reinforced concrete stubs are discussed. By using the analytical model of stress transfer and the criterion for punching shear fracture of the cladding reinforced concrete stub, the test results obtained hitherto can be analysed satisfactorily.

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A new type of structure, column-steel reinforced concrete and beam-steel, is came to be constructed now. The feature of this type of structure is the panel zone as the joint of framework of two different kinds of structure. This study was carried out to investigate the mechanical characteristic of this kind of column-beam connections, and in this paper to discuss the ultimate strength of panel, the experimental results are compared with the calculated results by the equations of A. I. J. and by the proposed model.

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In this paper, the method of direct design based on the limit analysis of high strength bolted tube flange joints subjected to tension is proposed. The validity of the method is confirmed through experimental results summarized below. (1) For the specimens in which the number of bolts is insufficient for required value, the failure was occured at the bolts. On the other hand, the tube was failed in the case when the number of bolts was sufficient. (2) Flange plates which. do not satisfy the required thickness deflected significantly out of its plane. The deflected shapes of flange plates were quite similar to the collapse mechanism assumed in the design, and the collapse loads of flange plates were well predicted by the design. (3) For the specimens in which both requirements as to the number of bolts and the flange thickness were satisfied, the deformation of bolts and flange plate were very small, eventually the tube was failed.

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This paper is the study on the constructed fill-up grounds of housing lots. In part 1, the engineering properties of constructed fill-up grounds weve particularly investigated. This study was carried out in the following two ways. 1. The ground investigation data of fill-up grounds were gathered from various parts of Japan and they were got into shape concerning kinds of soils composing fill-up grounds, standard penetration test data and Swedish penetration test data etc. 2. The static and dynamic deformation characteristics of soils in fill-up grounds weve examined in the laboratory by the static and dynamic triaxial compression test.

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The first part of this paper, part 1 dealed with the passive-earth-pressure of vertical and batter piles considered the friction between pile surface and soil. The after parts of this paper deal with an analysis method for the ultimate lateral of piles considered above mensioned the passive-earth-pressure and consist of the following 3 parts : Part 2 (this part) : An analysis method for the ultimate lateral resistance of short restrained piles. Part 3 : An analysis method for the ultimate lateral resistance of short free headed piles and in termediate long restrained piles. Part 4 : An analysis method for the ultimate lateral resistance of free and restrained long piles and arbitrary length of piles.

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Helical strakes are well-known as the devices to suppress the vortex excited oscillation of stacks. Hitherto the effectiveness of the strakes has been investigated by many wind tunnel experiments. However little data on the vibrations of actual stacks with the strakes have been reported. In order to find out the best configuration of the strakes to suppress the vibration of stacks, wind tunnel experiments of spring-sustained two-dimensional models were performed and an examination was made of the effects of the number, pitch angle and height of the helical strakes in reducing the vibrations. The necessary length of the strakes along height was investigated through the three-dimensional experiments in the wind tunnel. Based on the results of the wind-tunnel tests, the helical strakes were fitted to an actual steel stack. The measurements of the vibrations of the stack were carried out before and after the installation of the strakes. The observed maximum value of the double amplitude of the stack had been 80 cm before the installation and it became less than 5 cm after that. The designed helical strakes were proved to be successful. The sectionl areas of steel stacks are often determined by the conditions under the vortex excited oscillation rather than the maximum wind speed. In the design of the stack with helical strakes as mentioned above, the vortex excited oscillation need not be taken into account. As a result, the structure of the stack can be expected to be more economical than the plain stack without strakes.

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Elastic-plastic behavior of 3-stories steel reinforced concrete (SRC) frames with shear walls failing in flexure was investigated. Two specimens of the one-third of full scall were tested. Wall-reinforcements of TK 1 were uniformly reinforced by vertical and horizontal bars, and those of TK 2 were reinforced by diagonal braced bars. Axcil force, shear force and overturnning moment were loaded at the top of 3-stories. Wall-girders in shear walls did not provide. The ultimate loads, failure modes, hysteresis characteristics and degradation of flexural and shear rigidity were examined in detail. On the effective method of wall-reinforcements in shear walls, TK 2 was rich in earthquake resisting rather than TK 1 when shear strengths of both specimens were same. Because the diagonal braced bars restrained transverse extensions of shear walls and prevented to be developing shear deformation after diagonal tension cracks. The ductility factor of these structures could be expected to range from 6.2 to 8.9. The degradation factors of flexural and shear rigidity could be estimated by Eqs. (7) and (8). On ultimate flexural strength of shear walls, the analytical solutions obtained by the extended concept of adding component strengths of concrete, longitudinal reinforcements and steels were nearly equal to the experimental results.

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