Validation of Indian standard code provisions for fire resistance of flexural elements

• Main Authors: Aneesha Balaji, Praveen Nagarajan, Madhavan Pillai
• Format: Article
• Language: English
• Published: Prince of Songkla University 2015-04-01
• Series: Songklanakarin Journal of Science and Technology (SJST)
• Subjects: 500°C isotherm method; fire rating; transient thermal analysis; tabulated data; structural elements; reinforced concrete
• Online Access: http://rdo.psu.ac.th/sjstweb/journal/37-2/37-2-9.pdf

Fire resistance provisions in Indian codes are prescriptive in nature and provide only tabulated fire ratings for structural members. Eurocode EN 1992-1-2:2004 suggests simplified methods which include explicit equations for fire resistant design. The aim of this paper is to familiarize the simplified method, i.e., 500°C isotherm method. The procedure is customized for Indian conditions and a parametric study is done to determine the fire rating for flexural elements. Fire ratings recommended in IS 456:2000 is compared with strength criteria by using the 500°C isotherm method. It is also compared by thermal criteria obtained by heat transfer analysis of finite element model. Through these studies, it is shown that for most of the cross-sections, the fire rating obtained from the two methods is higher than that given in IS 456:2000 provisions and the increase in cover has significant effect in increasing fire rating only for lower values of cover to reinforcement.