Plasticity in steel is characterized by an appreciable amount of plastic flow which precede strain-hardening. Out- of plane flexural rigidities of steel plates stressed into the plastic flow range at the instance of plate buckling were evaluated in the previous paper. This study deals with buckling of steel plates with its four edges simply supported under biaxial normal stress. Buckling stress and strain of steel plates under biaxial compression are examined in the elastic, plastic flow and strain-hardening range by the moduli to relate the flexural rigidities derived in the previous paper. It is shown that the values of flexural rigidities are fairly influenced by the difference of stress point on von Mises'yield locus and then the behavior of plate buckling is also fairly influenced by it.

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In this paper, elasto-plastic behavior of framed structures under repeated variable loads with fixed loads is investigated. According to the unified and effective method proposed in the authors' previous paper, which is based on the well-established incremental procedure and applicable to the structure made of strain-hardening material as well as ideal elasto-plastic material, basic incremental equations for residual stresses, strains and displacements of the framed structure are derived. A beam-column model, based on the hybrid stress method and having no discretizing errors even in elasto-plastic region, is employed to analyze these equations. Three examples, respectively characterizing the different features of structural responses under repeated variable loads, are presented.

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Dynamic compliance of a circular disc is investigated for higher vertical modes. The vertical displacement of the disc is expressed in terms of a linear integral transformation of the normal stress of contact. This formula is derived solely from the dynamics of the elastic medium ; consequently, no restriction is imposed on the mechanical properties of the disc. The integral kernel, which is obtained for the first time, is expressed as a definite integral of some higher functions which are regular and can be evaluated easily. By solving simultaneously the basic equation presented here and the equation of motion of the disc, one can readily take the dynamical interaction between the disc and the elactic medium into account. The present formula is then examined numerically by applying to the rocking mode of a rigid disc whose result is known. The result obtained is identical to that of the conventional method.

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Buckling test of steel cylindrical shells subjected to combined bending and shear were conducted, using galvanized steel sheets as materials. Not only strength but also deformation characteristics of cylindrical shells affected by buckling which facilitate the evaluation of seismic resistance of cylindrical structures were made clear. A lower bound criterion for the buckling strength was obtained in a simple interaction formula. Deformation characteristics in the post-buckling region under monotonic transverse shear were found to be expressed by a simple empirical formula, and deformation characteristics under alternative transverse shear were found to be governed by a simple hysteresis rule.

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The inelastic response analysis of 10 story steel frames designed according to Japanese Building Standard Law was carried out, when subjected to strong ground motion. The vertical distribution of each member's plastic moment capacity was set to the usual design values varing discontinuouslly. In the analysis, the elasto-plastic property of each column or beam was taken account. The parameters of the analysis were the ratio of column-yield type frame to beam-yield type frame and the column/beam strength ratio. Using the results of the analysis, the yielding property of mixed type steel frames and the stability of response values were examined.

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In this paper, load displacement relationship models are proposed for reinforced concrete shear walls of nuclear reactor buildings based on the results obtained from (1) load tests using reduced scale models, and (2) numerical model tests using non-linear FEM analysis. Establishing a feasible earthquake-resistant design against 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 hysteresis loops and envelope curves which envelope apices of loops. Lateral displacement consists of shear and flexural displacement. In the case of reduced scale models, flexural displacement moreover consists of rotational displacement at the base. After careful consideration of the results of thirty-four reduced model tests and eighteen numerical model tests using non-linear FEM analysis, equations for calculating τ〜γ envelope curves were proposed. The computed envelope curves showed good agreement with experiments which were conducted not only by the authors but also other investigators.

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This paper describes the rigidity and strength of stud connectors based on the results of tests with 62 pushout pieces. The deckplate tested is for application to composite slabs and has a Lock rib in the center of its rib section. Since it is practical to weld the stud connectors by avoiding the Lock rib, we have arranged the stud connectors as in Figure 6. Among the considerable information we have received from the test results, the following 3 points are of particular significance. 1. In Figure 9, we have observed various failure modes. As shown in Figure 13-(a), the characteristics observed in the first half of the load-slip relationship of rib punching failure, which accompanies deckplate deformation, are the same as those resulting from concrete pullour failure. 2. The load-slip relationship of concrete pullout failure, and the first half of rib punching failure, are given in formula (7). 3. The opinion expressed by N. M. Hawkins, that strength is proportionate to pullout surface area, is made even more applicable by subtracting the skirt of pullout surface from projected pullout surface area. The coordinate axis shown at the bottom of Figure 16 represents effective projected pullout surface area. Test results show that, effective projected pullout surface area may be given by projected pullout surface area of the hypothetical section shown in Figure 18.

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In this report, (1) a fundamental set of differential equations governing the bending of r. c. slabs subjected to flexure in the linear elastic region is derived in consideration of the bond-slip of reinforcement and (2) a finite element formulation of the problem is implemented; whose subsequent solution in a few cases in point is presented as well as its examined results.

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