1 For each of the following concrete crosssections plain con

1. For each of the following concrete cross-sections (plain concrete slab and reinforced concrete column) shown, determine the maximum nominal aggregate size (MNA) that you will use. Given that: for Reinforced Concrete Section: Cover-40 mm. Stirrups 10 mm and all bars 16mm 700 110mm (a) Plain Concrete Section -350 (b) Reinforced Concrete Sectionn

Solution

a) According to ACI 211.1 , Maximum aggregate size is limited to one third of slab depth. So.. here MNA= 110mm X 1/3 = 36.67mm

b)for reinforced members 3/4th of minimum clear spacing between reinforcing bars. here minimum clear spacing between bars= 1/2 {350 -(10X2) - (40x2)-(16X3)} =101mm

maximum nominal size of aggregate= 101X3/4 =75.75mm