Estimating in Building Construction

Concrete 105

FIGURE 10.24.Grade Beam Details. 

FIGURE 10.25.Reinforcing Steel Quantity Takeoff.

EXAMPLE 10-12 GRADE BEAMS

The grade beam in the front of the building is 30 feet long. The
specifics of this grade beam are found in Figure 10.24. There are
four No. 5 horizontal bars and No. 3 bars used for stirrups at
12 inches on center (o.c.).

Add 10 percent for lap and wasteUse 61 pounds

Total weight55 pounds

0.376 pounds per foot

Total weight of stirrups (pounds)146 lf

Total length of No. 3 stirrups31 stirrups4.7¿146 lf

30 spacesUse 31 stirrups

Stirrup spaces 30 ¿> 1 ¿ stirrup spacing

Stirrup length (lf )1.167¿ 4 4.7¿ per stirrup

Stirrup length 1 ¿ 2 –  4

Add 10 percent for lap and wasteUse 138 pounds

Total weight125 pounds

Total weight of bars (pounds)120 lf1.043 pounds per foot

Total quantity of bars No. 5 (lf )4 bars 30 ¿ per bar120 lf

Estimating Wire Mesh. The square footage of the floor

area to be covered may be taken from the slab concrete cal-

culations. Check the sections and details for the size of the

mesh required. To determine the number of rolls required,

add the lap required to the area to be covered and divide

by 750 (the square footage in a roll). Waste averages about

5 percent unless much cutting is required; only full rolls may

be purchased in most cases.

Figure 10.25 is a detailed takeoff of all reinforcing bars

found in the foundation footings and walls.

EXAMPLE 10-13 WIRE MESH REINFORCING

Using the sample project found in Appendix A as an example, the

wire mesh is used for the basement floor and over the precast hol-

low core planks. Both of these areas are roughly the same square

footage. From Figure 10.23, this area is

Figure 10.25 is the workup sheet for all reinforcing found in

the building foundation. 

Labor. Figure 10.26 contains sample productivity rates

for tying and placing the reinforcing steel. In addition,

Figure 10.27 is the priced estimate for the reinforcing

steel.

Order 3 rolls of mesh

Rolls of mesh required(1,554 sf1.15)>750 sf per roll

Add 15 percent for lap and waste.

sf of concrete requiring mesh25.33¿30.67¿ 2 1,554 sf

sf of concrete requiring mesh 25 ¿ 4 –  30 ¿ 8 –  2

25 ¿ 4 –  30 ¿ 8 –.