International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 11 Issue: 04 | Apr 2024
p-ISSN: 2395-0072
www.irjet.net
Study on Structural Retrofitting of RC Column using Carbon Fibre Reinforced Polymer Amit Sodmise1, Ashutosh Sathe2, Prachi Laygude3, Vaibhav Pawar4, Shubham Vetal5 1Assistant Professor Civil Engineering, RMD Sinhgad School of Engineering, Warje, Pune, Maharashtra, India 2Student Civil Engineering, RMD Sinhgad School of Engineering, Warje, Pune, Maharashtra, India 3Student Civil Engineering, RMD Sinhgad School of Engineering, Warje, Pune, Maharashtra, India
4 Student Civil Engineering, RMD Sinhgad School of Engineering, Warje, Pune, Maharashtra, India 5Student Civil Engineering, RMD Sinhgad School of Engineering, Warje, Pune, Maharashtra, India
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Abstract - Reinforced concrete columns are critical
owing to their high strength-to-weight ratio, resistance to corrosion, excellent durability and ease of application. CFRP is particularly suitable foraxial strengthening of RC columns because of its confinement nature. CFRP is a new technology which is gaining traction in India for retrofitting of structural members.
structural elements whose performance under axial compressive loading is of importance. This experimental study investigates the compressive behaviour of circular and square Reinforced concrete columns wrapped with Carbon Fibre Reinforced Polymer (CFRP) composites. CFRP wrapping is an effective retrofitting technique that enhances the strength of concrete columns. A total of 12 columns, with 6 circular and 6 squares in cross-section, were tested under axial compression load. For each shape, 3 columns were wrapped with CFRP, while 3 were left unwrapped as specimens.
1.1 Fibre-Reinforced Polymer (FRP) Fibre-reinforced polymer (FRP) composites have an important application in providing confinement to reinforced concrete (RC) columns, enhancing their load-carrying. This strengthening method is based on the phenomenon that the axial compressive strength and ultimate axial compressive strain of concrete can be significantly increased through lateral confinement.
The objectives were to evaluate the influence of cross-sectional geometry and CFRP confinement on the load-carrying capacity, failure modes. Previous research has indicated that circular columns exhibit higher confinement effectiveness compared to square columns due to the continuous curvature providing more uniform confining stresses. The experimental results were critically analysed and compared with findings from relevant literature to validate this observation.
Externally bonding CFRP composites onto the surface of existing RC columns through wet layup or precured laminates provides supplemental strength and stiffness. The CFRP confines the inner concrete core and enhances its compressive capacity. It also provides additional shear resistance. Moreover, the reinforcement continues to function even after concrete crushing. Many previous studies have experimentally demonstrated that CFRP wrapping significantly increases the load carrying capacity of RC columns under axial, flexural and seismic loads. However, optimization of parameters like the CFRP stiffness, thickness, orientation, and layout is critical to maximize the strengthening efficiency. Various techniques have been employed to achieve confinement of columns using FRP composites. The most common method is in-situ FRP wrapping, where unidirectional fibre sheets or woven fabric sheets are impregnated with polymeric resins and wrapped around columns in a wet lay-up process, with the main fibers oriented in the hoop direction. Additionally, filament winding and prefabricated FRP jackets have also been utilized.
Additionally, the CFRP confinement method was compared to other retrofitting techniques, such as concrete column jacketing in terms of ease of application, cost-effectiveness, and performance enhancement. Key Words: Carbon Fibre Wrapping, Column, Experimental Testing, Reinforced Cement Concrete, Feasibility Study
1.INTRODUCTION Structural retrofitting refers to the addition and upgrade of structural components in existing buildings, bridges and infrastructure to make them safer, stronger and more resistant to forces. It enhances the load carrying capacity, stability, ductility, and service life of structures. Conventional techniques for strengthening RC columns like concrete or steel jacketing have several drawbacks. Addition of concrete jackets increases the column size and self-weight significantly. It also requires temporary formwork support and longer construction time. Fibre-reinforced polymer (FRP) composites have emerged as an advantageous strengthening material in civil engineering applications
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This project aims to investigate structural retrofitting of RC columns using externally bonded CFRP composites. The effectiveness of CFRP retrofitting will be studied through experimental modeling of CFRP wrapped columns.
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