Estimating in Building Construction

Excavation 89

removing fences and rails

removing boulders

wrecking old buildings

Foundations:

underpinning existing buildings

disconnecting existing utilities

clearing shrubbery

Excavation (including backfilling):

basement

footings

foundation walls

sheet piling

pumping

manholes

catch basins

backfilling

tamping (compacting)

blasting

grading (rough and fine)

utility trenches

grading and seeding lawns

trees

shrubbery

topsoil removal

topsoil brought in

9–19 Piles

Piles used to support loads are referred to as bearing piles.
They may be wood, steel “H” sections, poured-in-place con-
crete with metal casing removed, poured-in-place with metal
casing left in place, wood and concrete, or precast concrete.
The wide variations in design, conditions of use, types
of soil, and depth to be driven make accurate cost details dif-
ficult to determine unless the details of each particular job
are known. The various types and shapes available in piles
also add to the difficulty, particularly in concrete piles. It is
suggested that estimators approach subcontractors who spe-
cialize in this type of work until they gain the necessary
experience. Figure 9.42 gives approximate requirements for
labor when placing bearing piles.

Sheet piling may be wood, steel, or concrete. They are

used when the excavation adjoins a property line or when

the soil is not self-supporting. Sheet piling is taken off by the

surface area to be braced or sheet-installed.

Wood sheet piling is purchased by board feet, steel pil-

ing by 100 pounds (cwt), and concrete piling by the piece.

Depending on the type used, the quantity of materials

required must also be determined.

Sheet piling may be placed in the excavation and braced

to hold it erect, or it may be driven into the soil. No one way

is less expensive. Often, after the work is done, the piles are

removed (pulled).Pulling may require the employment of a

pile extractor for difficult jobs, or hand tools for the simple

jobs. Figure 9.43 gives approximate requirements for labor

when placing sheet piling.

Estimating. The first step is to determine exactly what

type and shape pile is required; next, the number of piles

required; and third, decide the depth that the piles will have

to be driven. With this information, the estimator can deter-

mine material quantities and their cost.

If the contractor’s crew will drive the piles, the next

determination should be the type of equipment required,

how many hours the work will take, and cost per hour. Then

the crew size, along with the hours and cost per hour

required, is calculated. To arrive at this, an estimate of the

linear footage placed per hour (including all cutting off,

moving around, etc.) must be made so that the total number

of hours required for the completion of the pile driving is

determined. In dealing with sheet piling, if the sheets are to

be pulled at the end of construction, the estimator must also

include a figure for this. Costs must also comprise mobiliza-

tion of workers, equipment, and material for pile driving,

and demobilization when the work has been completed.

FIGURE 9.42.Driving Bearing Piles.

FIGURE 9.43.Sheet Piles, Approximate Hours Required.