Part 56 (2/2)

The beam and girder forms were open troughs of the required dimensions, made of 2-in. plank, surfaced on inner faces. The form of centering for the roof slab consisted of a smooth, tight floor of 2-in. planks, extending between the open tops of column, beam and girder forms over the entire area between enclosing walls of the reservoir. The centering and the beam and girder forms were supported by 66-in. posts resting upon the floor below.

The regular carpenter gang consisted of a foreman carpenter at $5 per day, a carpenter at $3.50 per day, and two helpers at $2.75 per day.

During the early concrete work of making footings and floor, where forms were not required, the carpenter force was employed in erecting the steel skeleton for the walls. The upright bars were placed in position and secured by temporary wooden stays extending from the upper portion of bars to the surface of ground outside of excavation. These stays were removed after concreting had advanced to a sufficient height to hold the steel securely in place.

The wages paid the concrete gang which mixed and placed all the concrete and the carpenter gang which constructed and erected the forms and placed the reinforcement have been given above. The costs of construction materials on the site were:

Cement, per barrel $2.57 Sand, per cu. yd. 1.80 Stone, per cu. yd. 3.15 Lumber, per M. ft. B. M. 27.50

The quant.i.ties in the completed concrete structure were as follows:

Total volume of concrete in reservoir 704.71 cu. yds.

Total volume of steel reinforcement in reservoir. 5.57 cu. yds.

------ Total volume of material in completed structure. 710.28 cu. yds.

The steel was, therefore, about 0.8%.

Volume of material in structure exclusive of roof slab 648.35 cu. yds.

Volume of material in roof slab 61.93 cu. yds.

------ Total 710.28 cu. yds.

The cost of the structure per cubic yard of concrete, exclusive of the roof slab, was as follows:

Item. Per cu. yd.

Crushed stone $ 3.168 Sand .842 Cement 3.859 Reinforcement 4.959 Labor, mixing and placing concrete 1.721 Forms, labor and material 2.960 ------- Total $17.509

In constructing the roof slab the expanded metal reinforcement raised the unit cost. For this portion of the work the costs were:

Item. Per cu. yd.

Expanded metal reinforcement $ 5.241 Other items, same as above 12.550 ------- Total $17.791

The floor and the inside surface of reservoir walls were covered with a coating of cement mortar composed of one part Portland cement and one part sand. The wall plastering was from in. to in. thick; it was applied in two coats. The floor finish was laid in alternate strips about 1 in. thick and 3 ft. wide. After the strips first laid had hardened the remaining strips were laid, the edges being grouted to ensure tight joints.

The outside of walls and roof was covered with a coating of tar which was heated in an open kettle to a temperature of about 360 F. and then applied with a brush or mop.

The cost of wall and floor plastering was 44.4 cts. per square yard, itemized as follows:

Cement 26.4 cts.

Sand 2.6 cts.

Labor 15.4 cts.

----- Total 44.4 cts.

The cost of outside waterproofing was 4 cts. per square yard, distributed as follows:

Material 2.5 cts.

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