The Analysis And Research On Fire Resistance Of Reinforced Concrete Columns

Fire prevention is always a long-term and arduous task for us humankind. Fire resistance of structures is an important and difficult problem in structural engineering. Reinforced concrete structures are one of the most familiar structures in structural engineering, and its fire resistance is better than other structures such as steel structures and wood structures, but it will become disabled under conflagration too. To begin with, fire resistance of reinforced concrete columns should be studied, because columns are one of the most important elements in structures. If the columns are disabled, the whole structure will collapse or overturn. In addition, the research on fire resistance of reinforced concrete columns provide the foundation for study on other rising combined columns such as concrete filled steel tubular columns and steel reinforced concrete columns.Fire resistance of reinforced concrete columns is analyzed theoretically in this dissertation, combined with study on invalidation mechanism and control of reinforced concrete structures subjected to fire, which is one of the main projects of construction science and technology in Hunan province. The main contents studied in this dissertation are summarized as follows.(1) The most familiar thermal and mechanical behaviors of concrete and reinforcing steel bar at elevated temperature over the world are summarized and compared. Their sameness and difference are discovered.(2) The general methods to calculate the temperature field of reinforced concrete structures are summarized. The temperature field of reinforced concrete columns section is calculated in ANSYS, and the effects of different parameters such as design fires, surfaces exposed to fire, burning time, dimensions of cross section and concrete cover on the temperature field are analyzed.(3) The ultimate load bearing capacity of cross section of reinforced concrete columns exposed to fire is calculated through a program which is compiled in this dissertation, and the effects of different parameters such as dimensions of cross section, concrete cover, reinforcement ratio and compressive strength of concrete on the ultimate load bearing capacity are analyzed.(4) A program to calculate the fire resistance of restrained axially-loaded reinforced concrete columns is compiled in this dissertation, and the effects of different parameters such as dimensions of cross section, concrete cover,...