A 5-foot span (18 in, wide) of 8-in. Floor Block is found, by experiment, to stand 9,300 lbs. without breaking.

FIREPROOF LOAD OF 125 LBS. PER SQ. FOOT.

FIREPROOF LOAD OF 150 LBS. PER SQ. FOOT.

Fibre stress = 16,000 lbs. sq. inch.

This table does not include cost of columns or partitions, but simply the floor construction itself. The cost, including columns, would vary with the height of the story and the number of stories in the building. Interior non-supporting partitions composed of iron and 4" fireproof blocks and plastered both sides would cost 16 cents per square foot of area if built when the building is erected, or from 20 cents to 24 cents per square foot if constructed after the building is complete.

Transverse Strength of Flagging.

width of the stone in inches.

b

The following gives the breakiny loads in tons of 2,000 lbs. Weight being placed at the center of the span.

Thus a block of Quincy Granite 80 inches wide and 6 inches thick, resting on supports 36 inches in the clear, would be broken

Average weight of flagging per cubic foot per square foot as follows:

168 lbs. Weight

Cost of 100 Sq. Yds. 3 Coats Plaster, New York City.

IN POUNDS PER SQ. FOOT.

Slate, thick, on one-inch boards...

Corrugated iron, No. 20, on one-inch boards.

Lbs.

..10.0

7.5

6.0

3.5

4.0

.12.0

6.0

Corrugated iron and laths.

Slate or iron laths...

.......10.0

When slate is used on purlins of iron, the purlins should be 2′′ × 1′′ × 4", 10 pounds per yard, and spaced from 10" to 12" apart, the spacing between rafters (jacks and principals, or between jacks and jacks) should be about 5 feet.

COLUMNS AND GIRDERS.

Ultimate Strength of Rectangular Wooden Pillars Well Seasoned.

Let 1 = length of pillar in feet.

d = least width of side in inches.

Green timber has about half the strength of dry.

1

In the following table

is the ratio of length of post to least

d