The paper presents the results of theoretical, numerical and experimental researches of the stability of the equilibrium of metallic arches working in the elastic stage. A review of the literature on the stability of arches equilibrium is presented. The full-scale tests of three samples were performed under the action of various loading options before the onset of the critical state. The results are processed and compared with the values of the critical loads obtained in the analytical and numerical solutions of problems. A method for determining the critical load in SCAD Office 21.1 is proposed, taking into account the geometrically nonlinearity and bending moments in the form of a series of linear calculations. Satisfactory convergence of the obtained values is established (the error does not exceed 9%).