TY JOUR TI RESEARCH ON PRECAST REINFORCED CONCRETE FRAME SYSTEMS WITH FLAT CEILING KW precast concrete KW civil engineering KW flat ceiling KW reinforced concrete frame KW bearing frame JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Murtazin, R.S. AU Mukhamadeev, K.T. AU Sabitov, L.S. PY 2025 IS 10 PB Belgorod State Technological University named after V.G. Shukhov