Q1: If the diameter of longitudinal bars of a square column is 16 mm, the diameter of lateral ties should not be less than

ANS:B - 5 mm

In reinforced concrete columns, lateral ties (also known as stirrups or ties) are used to confine longitudinal bars and enhance the column's strength and ductility. These ties help in resisting shear forces and preventing buckling of longitudinal bars during loading. One common guideline for the minimum diameter of lateral ties is that it should not be less than one-fourth the diameter of the longitudinal bars. However, in many design codes and engineering practices, a more conservative approach is often taken to ensure adequate confinement and structural performance. Given that the diameter of the longitudinal bars of a square column is 16 mm, one-fourth of this diameter would be 14×16 mm=4 mm41​×16mm=4mm. However, as mentioned earlier, a more conservative approach is often taken to ensure structural safety. Therefore, a commonly accepted practice is to round up to the next standard or practical size for lateral ties. This is to ensure that there is sufficient material and strength in the ties to adequately confine the longitudinal bars and resist shear forces effectively. Typically, for practical construction and to ensure adequate strength, the minimum diameter of lateral ties would be rounded up to the next standard size, which is commonly 5 mm in many construction practices. So, in summary, while the calculation may suggest a minimum diameter of 4 mm based on one-fourth the diameter of the longitudinal bars, in practice, a more conservative approach is often taken, and the minimum diameter of lateral ties is rounded up to 5 mm to ensure structural safety and adequacy. Therefore, the correct answer is 5 mm.