Lapped splices in tensile reinforcement are generally not used for bars of size larger than A. 18 mm diameter B. 24 mm diameter C. 30 mm diameter D. 36 mm diameter

The correct answer is: D. 36 mm diameter

Lapped splices in tensile reinforcement are generally not used for bars of size larger than 36 mm diameter because they are not as effective as other types of splices, such as mechanical splices or welded splices. Lapped splices are more likely to fail under tensile loads, and they can also create stress concentrations in the concrete.

Here is a brief explanation of each option:

• Option A: 18 mm diameter. Lapped splices can be used for bars of this size, but they are not as effective as other types of splices for larger bars.
• Option B: 24 mm diameter. Lapped splices can be used for bars of this size, but they are not as effective as other types of splices for larger bars.
• Option C: 30 mm diameter. Lapped splices can be used for bars of this size, but they are not as effective as other types of splices for larger bars.
• Option D: 36 mm diameter. Lapped splices are generally not used for bars of this size because they are not as effective as other types of splices.