International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 09 Issue: 07 | July 2022
p-ISSN: 2395-0072
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EXPERIMENTAL STUDY ON F.R.P.S. STRENGTHENING REINFORCED CONCRETE BEAMS AT ELEVATED TEMPERATURE Mohd. Shadab Qurashi1, Mohd Kashif Khan2, Aleem Aijaz3 1M.Tech
Research Scholar, Department of Civil Engineering, Integral University, Lucknow (India) Professor, Department of Civil Engineering, Integral University, Lucknow (India) 3Lecturer, Department of Civil Engineering, University Polytechnic, Integral University, Lucknow (India) ---------------------------------------------------------------------***--------------------------------------------------------------------the FRP rebar’s are an important property for mechanical Abstract – Concrete with steel reinforcement is the perfect 2Associate
bonding to concrete. There is no standardized classification of surface deformation patterns 3 . The nominal diameter of a deformed FRP bar is equivalent to that of a plain round bar having the same area as the deformed bar. When the FRP bar is not of the conventional solid round shape (that is, rectangular or hollow), the outside diameter of the bar or the maximum outside dimension of the bar will be provided in addition to the equivalent nominal diameter.
combination for any construction. So, to enhance its properties different fibers are used. Basalt Fiber Reinforced Polymer (BFRP) and Glass Fiber Reinforced Polymer (GFRP) are used in this work to improve its fire resisting properties under elevated temperature. Basalt fiber and glass fiber increases the strength of concrete but if we put the concrete under fire, its strength decreases. So, several experimental studies are done in this work to improve its fire resisting properties with minimum decrease in strength or we can also say with lesser decrease in strength
FRP bars made of continuous fibres (aramid, carbon, glass, or any combination) should conform to quality standards. FRP reinforcing bars are available in different grades of tensile strength and modulus of elasticity. The tensile strength grades are based on the tensile strength of the bar with the lowest grade being 414 MPa (grade F60) and the highest strength of 2,069 MPa (grade F300)[3]. For the modulus of elasticity grade the minimum value is prescribed depending on the fibre type. For design purposes, the engineer can select the minimum modulus of elasticity grade that corresponds to the chosen fibre type for the member or project. For example, an FRP bar specified with a modulus grade of E5.7 indicates that the modulus of the bar should be at least 39.3GPa
Key Words: BFRP, GFRP, Fire resisting, HR Aluminium Paint 5000C, RC Beams
1. INTRODUCTION In the recent years, there was a strong need to repair/strengthen concrete structures due to material deterioration, environmental effects, misuse or overloading. As an alternative to traditional strengthening techniques, Fiber-Reinforced Polymers (FRP) is being increasingly used due to their desirable attributes. Although FRP strengthening proved efficiency in practice, there are increasing concerns related to their performance in case of fire. Polymer materials exhibit a change in mechanical properties when exposed to temperature higher than 80– 1200C, referred to as the glass transition temperature (Tg). This causes serious damage to the bond between the FRP and the concrete surface and consequently the structural integrity and effectiveness of the FRP strengthening will be severely threatened or may be some design codes such as ACI 440-2008] do not recommend the use of FRP internal or external reinforcements for structures in which fire resistance is essential[1]
FRP materials are highly combustible and burn when exposed to fire. A large amount of combustible gases, ignite, release heat and propagate flame are generated during burning of FRP.[5] The emitted smoke, which affects visibility, hinders ability of the occupants to escape and poses difficulties for fire fighters to conduct evacuation operations and suppress the fire.
Other codes limit strengthening by externally bonded FRP to only 40% of the capacity, for the un strengthened concrete element to be sufficient to resist the service loads .Elevated temperature conditions occurring in case of fire have damaging effects on concrete structures. 1.1 TYPES OF THE FRP BARS Surface geometries of the FRP reinforcements commercially available include ribbed, sand coated then wrapped and sand coated again.[2] The physical characteristics of the surface of
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