Q1: The diameter of main bars in R.C.C. columns, shall not be less than

ANS:D - 12 mm

The diameter of main bars in reinforced concrete columns is an important aspect of structural design, as it directly influences the load-carrying capacity, ductility, and overall performance of the columns. The minimum diameter of main bars in R.C.C. columns is typically specified to ensure an adequate amount of reinforcement and to facilitate proper concrete placement and compaction around the bars. Among the options provided, the most common minimum diameter for main bars in R.C.C. columns is: 12 mm12mm This diameter ensures sufficient strength and ductility while allowing for proper concrete consolidation around the reinforcement bars during construction. However, it's important to note that specific design requirements may vary based on factors such as structural loads, column dimensions, and design codes. Always refer to applicable design standards and project specifications for precise requirements regarding reinforcement diameter in R.C.C. columns.