Enhanced Sustainability through Strengthening of Existing Structures with Natural Fibre Ropes

Natural fibre products have recently been introduced to the construction industry owing to their advantages, such as cost-effectiveness, lightweight, corrosion resistance, and low carbon footprint. Such products have been utilised for flooring, roofing, and insulation systems, and more limitedly, as a replacement for steel reinforcements in reinforced concrete (RC) members. This study investigates the efficacy of strengthening existing structures by post-tensioning them using unbonded ropes made from natural jute fibre (NJF). Analytical investigation, finite element (FE) analysis, and experimental campaign have been carried out to evaluate the effect of post-tensioning with unbonded NJF ropes on the flexural behaviour of RC beams. The proposed post-tensioning technique has improved the load-carrying capacity by 18.6% and reduced the deflection of the beam at the service load by 45%. The investigation disclosed that the post-tensioning ratio had dominated the behaviour proportionally, i.e., the more post-tensioning applied, the better capacity and serviceability performance achieved. Further, such a technique is found to possess the potential to overcome the serious issue associated with post-tensioning, represented by corrosion of steel cables, and offering more flexibility by enabling the replacement of the unbonded ropes when needed. Hence, natural fibre ropes were recommended to strengthen existing structures for better performance and sustainability. The outcome represented by enhancing the flexural performance of structural elements and controlling the serviceability by post-tensioning using natural jute fibre (NJF) ropes is deemed promising, especially when considering the advantages of this green material and its positivity from an environmental perspective. This innovative technique may set the base for further employment of natural fibres in the construction industry to mitigate the increasing impact of construction, which continuously degrades the planet.