TY JOUR TI MODAL ANALYSIS OF MULTILEVEL CONCRETE FRAMEWORK AFTER FIRE EXPOSURE KW fire impact KW fire accident KW fire resistance KW reinforced concrete KW vibrations JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Chapidze, O.D. AU Zhukov, D.I. PY 2019 IS 4 PB Belgorod State Technological University named after V.G. Shukhov