Structural Assessment and Rehabilitation of High-Rise Buildings: A Case Study of RNA Mirage Tower Mumbai

The rapid pace of urbanization and the rising demand for space in metropolitan areas have led to a surge in the construction of high-rise buildings. However, the long-term performance and durability of these structures often suffer due to inadequate construction practices and poor maintenance. This study presents a comprehensive case analysis of the RNA Mirage building, a G+40 residential tower located in Worli, Mumbai, which exhibited significant structural distress after 15 years of service. Visible signs of deterioration included widespread spalling, reinforcement corrosion, water leakage, and cracking in both structural and non-structural elements. A detailed investigation was conducted using a combination of visual inspections, non-destructive testing (NDT), and semi-destructive techniques. These included the Rebound Hammer Test, Ultrasonic Pulse Velocity Test, Half-Cell Potential Test, Carbonation Depth Test, and Core Sampling. The results indicated considerable variation in the compressive strength of concrete, with some readings as low as 25 N/mm², highlighting poor original construction quality and increased permeability. This facilitated the ingress of harmful agents such as chlorides and carbon dioxide, leading to corrosion of steel reinforcement and concrete degradation. Based on the assessment, a structured rehabilitation process was implemented, including the use of polymer-modified mortar, corrosion inhibitors, guniting, and waterproofing treatments. This case underscores the critical need for quality control during construction and the importance of periodic maintenance in preserving the safety and longevity of high-rise structures. Key recommendations are provided to improve durability in future projects and minimize the need for extensive structural rehabilitation.