Estimating in Building Construction

86 CHAPTER NINE

From Example 9-14, the basement excavation is 10,997 bcf.

Backfill (bcy)4,134 ccf> 27 cf per cy 153 ccy

Backfill (bcf)10,997 bcf6,746 cf 117 cf4,134 ccf

Footing volume

Backfill (bcf )General excavationBuilding volume

FIGURE 9.39.Footing Backfill.

FIGURE 9.37.Backfill Section.

FIGURE 9.38.Backfill Section.

Equipment:Dozer (120 hp) at $16.85 per hour

Dozer work rate:100 ccy per hour (Figure 9.26)

Operator:$18.30 per hour

Laborer:$11.50 per hour

Mobilization:1.5 hours

$139.95 

Total cost$54.90$34.50$50.55

Equipment cost ($) 3 hours$16.85 per hour$50.55

Laborer cost ($) 3 hours$11.50 per hour$34.50

Operator cost ($)3 hours$18.30 per hour$54.90

3 hours

Total hours1.5 hours1.5 mobilization hours

Backfill time (hours)153 ccf>100 ccy per hour1.5 hours

EXAMPLE 9-18 BACKFILLING THE FOUNDATION WALLS

There are two ways in which the quantity of backfill can be deter-
mined. Both will yield virtually the same answer. The first is to sub-
tract the area of the footing from the area backfill and multiply that
number by the length of the footing. Figure 9.40 is a sketch of the
backfill requirements. The excavation for the footing was discussed
in Example 9-15.

7,589 ccf

Volume of backfill (ccf)9,640 bcf2,051 cf

2,051 cf

Volume in foundation and footing (cf )974 cf1,077 cf

1,077 cf

Volume in foundation wall (cf ) 3 ¿1.167¿307.67¿

Volume in foundation wall (cf) 3 ¿ 1 ¿ 2 –  307 ¿ 8 –

974 cf

Volume of footing (cf)3.167¿ 1 ¿307.67¿

Volume of footing (cf) 3 ¿ 2 –  1 ¿ 307 ¿ 8 –

Alternately, the area of backfill can be figured as shown in Figure 9.41

by figuring the area and by multiplying that amount by the length.

281 ccy

Volume of backfill (ccy)7,589 ccf>27 cf per cy

FIGURE 9.40.Continuous Footing Backfill.