Experimental and Analytical Comparative Analysis on Effectiveness of Different Wrapping Techniques for Two Way RC Slabs Using Different International Guidelines

Enhancement of strength and performance of building members is the need of hour for the existing structures. Every time the slab strengthening is the most challenging task, since very few techniques are available as on date and the productivity of those are under research stage (Hollaway in Constr Build Mater 24:2419–2445, 2010) [1]. In this scenario, fibre reinforced polymer composites promotes the research activity due to the various advantages of these materials over steel (Anakal et al., in Int J Adv Sci Eng Technol 6(1), 2018) [2]. The Fibre Reinforced Composites (FRP) such as CFRP (Carbon Fibre Reinforced Polymer) composite and GFRP (Glass Fibre Reinforced Polymer) composite materials used, seems to be not so economical in the present situation of technology and its application. However, Basalt fibres which are very much used in different engineering fields and their application are limited in Structural and construction industries. In this work, strengthening of RC slabs was done using wrapping technique using Basalt Fibre Reinforced Polymer (BFRP) composites by means of hand layup method and wet layup technique. Unidirectional knitted fibres were attached to the surface of the slab in different configurations (plus and square), in a way that the FRP and the RC slab performs as single structure when subjected to load. The effectiveness of the retrofitting method was measured by means of the deflection and crack width on working loads attained by the RC slabs. The deflection and crack width on working loads obtained from the experiment were compared with guidelines of ACI 440.2R-17 (ACI 440.2R-17, Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures) [3], ISIS CANADA Design Manual No. 3 (ISIS CANADA Design Manual No. 3 2007, Reinforcing concrete structures with fibre reinforced polymers) [4], Fib Bulletin14 (Fib Bulletin14-2001, Externally bonded FRP reinforcement for RC structures) [5], CNR DT 200 R1/2013 (CNR DT 200 R1/2013, Guide for the design and construction of externally bonded FRP systems for strengthening existing structures) [6] /CNR-DT 200/2004 (CNR-DT 200/2004, Guide for the design and construction of externally bonded FRP systems for strengthening existing structures) [7] and TR55 (TR55, Design guidance for strengthening concrete structures using fibre reinforced composite materials) [8]. The observations made are presented along with a comparative statement of analytical and experimental results.