Flexural Strengthening of Fire Damaged Reinforced Concrete Structural Member

Abstract

Fire causes extreme damage leading to huge loss of life and property. An extensive damage also occurs to structural members when exposed to fire. Therefore, after fire structural members need to be strengthened to restore their load carrying capacity to withstand the future service loads. The selection of strengthening technique depends on the residual capacity of fire exposed structures and required ultimate load carrying capacity. Further if strengthen structure is exposed to fire in future then strengthening techniques should also have good fire performance and remain intact with the base concrete. In this paper, efforts have been made to study and understand the effectiveness of fire damaged reinforced concrete jacked flexural member. Limited information is available on the flexural performance of fire damaged strengthen members with reinforced concrete jacket and concrete jacket. This work presents a simple and efficient technique to strengthen reinforced concrete beam in flexure using traditional materials. This paper discusses in detail the strengthening strategy program of two-hour fire exposed beam to restore its original load carrying capacity. The reinforced concrete beam is simulated in finite element-based software to compute the thermal profile, which used to calculate residual load capacity. The obtained result of thermal distribution and residual moment capacity are compared with proposed literature models and design code equations. The performance of fire damaged and strengthen beams are studied through moment-curvature relationship load-deflection behaviour. This paper provides a simplified analytical approach to determine the residual capacity of fire damaged beams along with that expected improvements in their capacity after strengthen by reinforced concrete and concrete jacket.