These figures give a unit cost of $12.41 per cu. yd. for molded columns, and of $15.07 per cu. yd. for molded girders, The columns were erected by a Browning locomotive crane, which lifted and carried them to the work and up-ended them into place. To facilitate lifting the columns from the molding bed a 1½-in. pipe 8 ins. long was cast into both ends; pins inserted into these sockets provided hitches for the tackle. The column was lifted off the molding bed and blocked up, then iron clamps were attached, one at each end, as shown by Fig. 243. A gang of 1 foreman and 14 men erected from 5 to 7, or an average of 6 columns per 10-hour day. The average wages of the erecting gang were 21 cts. per hour. The cost then of column erection was (14 × $2.10) ÷ 6 = $5.25 per column, or $2.63 per cu. yd. of concrete.
Fig. 244.—Sketch Showing Sling for Erecting 50-ft. Roof Girders.
The roof girders had 1-in. eye-bolts 24 ins. long cast into them vertically about 4 ft. from the ends. They were lifted off the molding bed by tackle by the locomotive crane to these eye-bolts and blocked up to permit the adjustment of the sling. This sling is shown by the sketch, Fig. 244, and as will be observed acts as a truss. At first it was used without the vertical, but the cantilever action of the unsupported ends caused cracks. The girders were loaded onto cars by the locomotive crane and taken to the work, where they were hoisted and placed by a gin pole. The girder erecting gang consisted of 1 foreman and 14 men, working a 10-hour day at 21 cts. per hour. This gang erected four girders per day, at a cost of (15 × $2.10) ÷ 4 = $7.87 per girder, or $1.57 per cu. yd. of concrete.
The cost of girders and columns in place was thus about as follows:
| Columns: | Per unit. | Per cu. yd. |
| Molding | $25.00 | $12.50 |
| Erecting | 5.25 | 2.63 |
| ——— | ——— | |
| Totals | $30.25 | $15.13 |
| Girders: | ||
| Molding | $75.00 | $15.00 |
| Erecting | 7.87 | 1.57 |
| ——— | ——— | |
| Totals | $82.87 | $16.57 |
Fig. 245.—View Showing Method of Handling Roof Slabs.
In this same building the roof was composed of 12×6¼ ft.×4-in. slabs molded in tiers; a slab was molded and when hard was carpeted with paper and the form moved up and a second slab molded on top of the first. This operation was repeated until a tier of slabs had been molded. By molding each slab with a 3-in. overlap, as shown by Fig. 245, they could be easily separated by lifting on hooks inserted under the overhanging ends. Each slab contained 0.925 cu. yd. of concrete and about 116¾ lbs. of reinforcement. The cost of molding one roof slab, including materials, forms and labor, was as follows:
| Materials: | Per slab. | Per cu. yd. |
| 1 bbl. cement, at $1 | $1.000 | $1.081 |
| 1.06 tons stone, at $0.60 | 0.636 | 0.687 |
| 116¾ lbs. steel, at 2¼ cts. | 2.647 | 2.862 |
| ——— | ——— | |
| Total | $4.283 | $4.630 |
| Forms: | ||
| Lumber and making | $0.104 | $0.112 |
| 92 sq. ft. paper, at 33⅓ cts. per 500 sq. ft. | 0.055 | 0.059 |
| Labor erecting and removing | 0.5625 | 0.608 |
| ——— | ——— | |
| Total | $0.7215 | $0.779 |
| Mixing, Hauling and Placing: | ||
| Mixing | $0.222 | $0.240 |
| Hauling | 0.025 | 0.027 |
| Placing concrete and steel | 0.170 | 0.183 |
| ——— | ——— | |
| Total | $0.417 | $0.450 |
| General Expenses: | ||
| Housing and heating | $0.700 | $0.757 |
| Superintendence, power, etc. (10%) | 0.612 | 0.661 |
| ——— | ——— | |
| Total | $1.312 | $1.418 |
| Grand totals | $6.7335 | $7.277 |