Gichko V. Calculation of stability of flexible reinforce-concrete bars by a deformation method

The analytical dependencies are obtained for the deflections determination by a cubic spline approximation of a deflected axis. The "accurate" procedure of stability calculation by means of the deformation method using the curvilinear diagrams of concrete and reinforcement straining is developed for the flexible eccentric-compressed reinforced concrete elements. The simplified procedure is elaborated to determine the critical loads for flexible eccentric-compressed elements. The procedure is based on calculating the most stressed section of an element by means of the unstrained scheme taking into account a longitudinal fold. The physics experiment was carried out for the confirmation of the developed methods appropriateness. The strength and deformation properties of concrete and used reinforcement, as well as the complete diagrams of concrete deformation were determined. The experimental data were obtained regarding the influence of the load application eccentricity value on the load-bearing capacity (stability) of flexible reinforced concrete elements, and the behavior of concrete as a part of standard sections of the flexible reinforced concrete eccentric-compressed hinge-supported elements under the short-term impact of a load. The assessment of accuracy and reliability is performed by comparing the results of calculation performed in compliance with the developed procedures and the experimental data. The comparison results verify that the proposed calculation procedures sufficiently represent the process, which they model, in quantitative and qualitative aspects. Key words: stability, load-bearing capacity, "accurate" procedure, simplified procedure, deformation method.