This spacing is also used coming outwards of beams (including bottom tie beam). The L's (or hooks) at the bottom of the column vertical bars are joined to the matting. In answer to your last question. We start the stirrups at the L, so it is typically 2/3+ of the way down ...
Beam or column, The minimum essential cover thickness usually rangesbetween 25mm to 35 mmdepending on the ecological conditions present during the building’s once-over life. A cover placed in the beam at the bottom and sometimes cover the tie with the side face of steel. Is 456 a Column C...