On deformation criteria of a special limit state of eccentrically compressed elements of RC building frames

At accidental impacts caused by the sudden removal of a load-bearing element of the building frame, the stress-strain state of the sections of eccentrically compressed structural elements such as columns, pylons, braces and belts of trusses, etc. becomes more disadvantageous than their stress-strain state at the stage of normal operation. The factors that lead to such a situation are sharp increase in the eccentricities of loads attaching, slenderness of cross sections, corrosion, initial curvature and mechanical damages. In these cases, buckling scenario for the exhaustion of their bearing capacity is a possible scenario. The paper proposes an approach to the obtaining of deformation criteria for assessing the special limiting state of eccentrically compressed bar elements of reinforced concrete frames. Such an approach is based on the use of a combination of nonlinear deformation analysis and nonlinear stability analysis. Paper shows that the limiting values of deformations for the considered reinforced concrete element can be determined by the criteria of strength or buckling, depending on the ratio of the forces acting in the sections of the structural element.