lity Analysis of Reinforced Concrete Building Frames under Ultimate States

Abstract

The paper proposes the method for stability analysis of structurally and physically nonlinear systems of reinforced concrete multi-story building frames under ultimate states caused by accidental actions. The stress-strain state in the considered structural system is determined according to the deformed scheme considering the influence of buckling, physical nonlinearity and changes in the stress-strain state of elements due to structural changes. At the same time, the dynamic overloads of structural elements are determined by the quasi-static method. The stiffness matrix of the structural system with nonlinear elastically semi-rigid restraints of bar element interface nodes is obtained using the method of initial parameters. The finite difference method is applied to solve the two-dimensional problem of calculating the stress-strain state of the beam-column joint element of a reinforced concrete frame. The authors propose energy criterion written through the increment of potential strain energy from external influence as a criterion for stability failure of eccentrically compressed elements of reinforced concrete frame of a multi-story building.