The circular construction is the strongest, because it takes advantage
of the lineal, instead of the breaking strength of the lumber. Each row
of boards running around the barn forms a hoop that holds the barn
together. A barrel, properly hooped and headed, is almost indestructible,
and much stronger than a box, altho the hoops are small. This strength
is because the stress comes on the hoops in a lineal direction. Any
piece of timber is many times stronger on a lineal pull than on a
breaking stress. Take for example a No. 1 yellow pine 2 x 6, 16 feet
long, with an actual cross section of 1-5/8 x 5-5/8 inches. If placed
on edge and supported at the ends, as a joist, the limit of safety for a
load evenly distributed is 642 pounds, while the limit of safety for a
load in the lineal direction of the same piece of timber is 12,800
pounds, or twenty times as great.
[Illustration: FIG. 5. IN COW STABLE, SHOWING SILO AND FEED ALLEY IN
CENTER OF BARN; STANCHIONS ON RIGHT, MILK SCALES AND RECORD SHEET ON
LEFT.]
All exposed surfaces of a round barn are circular, as both the sides and
roof are arched, which is the strongest form of construction to resist
wind pressure; besides, the wind, in striking it, glances off and can
get no direct hold on the walls or roof, as it can on the flat sides or
gable ends of a rectangular structure. If the lumber is properly placed
in a round barn, much of it will perform two or more functions. Every
row of siding boards running around the building serves also as a brace,
and the same is true of the roof boards and the arched rafters. If the
siding is put on vertically and the roof built dome-shaped, no
scaffolding is required inside or out. These are points of economy in
the round construction.