Estimating in Building Construction

142 CHAPTERTWELVE

FIGURE 12.8.End Anchorage.

EXAMPLE 12-2 BAR JOISTS

Determine the quantity of bar joists required to frame the roof
in drawing S2.2 in Appendix A (Figure 12.2). From these draw-
ings, the bar joist quantity table, as shown in Figure 12.9, can be
developed.

From Figure 12.7, the 18K3 weighs 6.6 pounds per foot and
the 24K6 weighs 9.7 pounds per foot.



Labor. The time required for the installation of steel joists
may be taken from Figure 12.10. The hourly wages are based
on local labor and union conditions. A crane is usually
required for joists over 300 pounds. The crane would reduce

Total weight of bar joist5.9 tons

Total weight of bar joist11,749 pounds>2,000 pounds per ton

Total weight of bar joist3,795 pounds7,954 pounds

7,954 pounds

Pounds of 24K6 820 ft9.7 pounds per foot

3,795 pounds

Pounds of 18K3 575 ft6.6 pounds per foot

Linear feet of 24K6 35 ¿ 8 –  23  820 ft

Linear feet of 18K3 25 ¿ 23 575 ft

FIGURE 12.9.Bar Joist Takeoff.

FIGURE 12.10.Bar Joist Installation

Productivity Rates.

Labor Hours

Joist Type per Ton

J & K, up to 30 Ft. 5.5 to 9.0

J & K, over 30 Ft. 4.5 to 8.0

LJ & LH 4.0 to 6.0

DLJ & DLH 4.0 to 6.0

installation time on large projects and justify the cost of the

crane, even if the joist weights were less than 300 pounds.

12–5 Metal Decking

Metal decking is used for floor and roof applications. Depend-

ing on the particular requirements of the job, a wide selection

of shapes, sizes, thicknesses, and accessories are available.

Roof applications range from simple decks over which

insulation board and built-up roofing are applied, to forms

and reinforcing over which concrete may be poured, and to

decking that can receive recessed lighting and has acoustical

properties. Depending on the type used and the design of

the deck, allowable spans range from 3 feet to about 33 feet.

Decking for floor applications is equally varied from the

simplest type used as a form and reinforcing for concrete to

elaborate systems that combine electrical and telephone out-

lets, electrical raceways, air ducts, acoustical finishes, and

recessed lighting.