RCC slab culvert: excavation, PCC foundation, slab

The drawing is not available, so the method is shown on a stated set of dimensions; the same steps are used for any slab culvert.

Assumed dimensions

• Clear span $3.00$ m, bearing of slab $0.40$ m on each abutment; slab thickness $0.30$ m.
• Width of culvert (measured across the road, i.e. along the stream) $4.80$ m (4.00 m roadway + 2 kerbs of 0.40 m); this is also the length of each abutment.
• Each abutment foundation: PCC (1:3:6) $1.40$ m wide $\times$ $0.30$ m thick $\times$ $4.80$ m long, with the bottom of excavation $1.50$ m below the ground.

a) Earthwork in excavation

$V = 2 \times 1.40 \times 4.80 \times 1.50 = 20.16$ m³

b) PCC (1:3:6) in foundation

$V = 2 \times 1.40 \times 4.80 \times 0.30 = 4.032$ m³

c) PCC (1:2:4) for RCC slab

Slab length $= 3.00 + 2 \times 0.40 = 3.80$ m; $V = 3.80 \times 4.80 \times 0.30 = 5.472$ m³

Answer (for the assumed drawing): excavation = 20.16 m³; PCC 1:3:6 = 4.032 m³; concrete 1:2:4 in slab = 5.472 m³. For the actual drawing, substitute its dimensions in the same expressions.