Behaviour of Reinforced Concrete Columns of Various Cross Sections Subjected to Fire
Fire resistance is one of the crucial design regulations which are now mandatory in most of the design codes. Therefore, a thorough knowledge of behaviour of structures exposed to fire is required in this aspect. Columns are the most vulnerable structural member to fire as it can be exposed to fire from all sides. However, the data available for fire resistant design for columns are limited. Hence the present work is focused on the effect of cross sectional shape of column in fire resistance design. The various cross sections considered are Square, Ell (L) Tee (T) and Plus shape. Also the effect of size and shape and distribution of steel reinforcement on fire resistance of columns is studied. As the procedure for determining fire resistance is not mentioned in Indian Standard code IS 456 (2000) the simplified method (500 degC isotherm method) recommended in EN 1992 1 2:2004 (E) (Eurocode 2) is adopted. The temperature profiles for various cross sections are developed using finite element method and these profiles are used to predict fire resistance capability of compression members. The fire resistance based on both numerical and code based methods are evaluated and compared for various types of cross section.