Q1: The minimum clear cover for R.C.C. columns shall be

ANS:C - greater of 25 mm or diameter

The correct minimum clear cover for RCC columns, as per most building codes and standards, including the Indian Standard IS 456:2000, is typically specified as: Greater of 25 mm or the diameter of the largest barGreater of 25 mm or the diameter of the largest bar This means that the minimum clear cover requirement is determined by taking the larger value between 25 mm and the diameter of the largest reinforcing bar used in the column. The reason for this requirement is to ensure adequate protection for the reinforcement bars against environmental factors such as corrosion and fire, as well as to provide sufficient concrete cover to prevent the bars from being exposed or damaged during construction and throughout the service life of the structure. Adequate clear cover helps to maintain the durability and structural integrity of the column by reducing the risk of corrosion-induced deterioration of the reinforcement, which could compromise the overall performance and safety of the structure. Therefore, the correct answer is: Greater of 25 mm or diameterGreater of 25 mm or diameter