TY JOUR TI DISPLACEMENTS IN PIVOTAL SYSTEMS OVER ELASTICITY LIMIT KW pivotal system KW static undefinable beam KW elastic-plastic deformation KW state of material of construction element KW displacements under loading JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Yuriev Alexander, A.G. AU Smolyago, N.A. AU Yakovlev, O.A. PY 2022 IS 7 PB Belgorod State Technological University named after V.G. Shukhov