What does 350x350 rc columns 4n20 vertical r10-300 ties typical mean?

Answer 1

This means that the columns are 350x350 mm in dimension and reinforced with 4 numbers of 20 mm diameter bars vertically. The ties used are R10-300, which implies that they are circular ties with a diameter of 10 mm spaced at 300 mm intervals. This is a typical reinforcement detail used in construction.