Szukana fraza: [Abstract = To find limit parameters of these actions the extreme energetic principle is suggested what result in the bilevel mathematic programming problem statement. The limit parameters of load actions are found on the first level of optimization. On the second level the power of the constant load with equilibrium preloading is maximized and\/or system cost is minimized. The examples of using the proposed methods are presented and geometrically hardening composite steel\-concrete system are taken into account.]