Welcome
to BostonConcreteCutting.Com

*“We
Specialize in Cutting Doorways and Windows in Concrete Foundations”*

**Are You in ****Carver Massachusetts****? Do You
Need Concrete Cutting?**

**We Are Your Local
Concrete Cutter**

**Call ****781-519-2456**

**We Service Carver MA
and all surrounding Cities & Towns**

Concrete
Cutting Carver MA Concrete Cutting
Carver Massachusetts

Concrete
Cutter Carver MA Concrete
Cutter Carver Massachusetts

Concrete
Coring Carver MA Concrete Coring
Carver Massachusetts

Core
Drilling Carver MA Core
Drilling Carver Massachusetts

Concrete
Sawing Carver MA Concrete Sawing

Concrete
Cutting MA Concrete
Sawing Carver Mass

Concrete
Cutting Carver Mass Concrete Cutting
Carver Massachusetts

Concrete
Cutter Carver Mass Concrete Coring
Mass

Core Driller Carver MA Core
Drilling Carver Mass

This
buckling can be avoided, and the bars made mutually self-supporting, by means
of the bands which are placed around the concrete column. These bands are
usually 1-inch or 5-inch round or square bars. The specifications of the
Prussian Public Works for 1904 require that these horizontal bars shall be
spaced a distance not more than 30 times their diameter, which would be 712
inches for i-inch bars, and 111 inches for *-inch bars.
The bands in the concrete column are likewise useful to resist the bursting
tendency of the concrete column, especially when it is short. They will also
reinforce the concrete column against the tendency to shear, which is the
method by which failure usually takes place. The angle between this plane of
rupture and a plane perpendicular to the line of stress is stated to be 60°.
If, therefore, the band are placed at a distance apart equal to the smallest
diameter of the concrete column, any probable plane of rupture will intersect
one of the bands, even if the angle of rupture is somewhat smaller than 600. The
unit working pressure permissible in concrete columns is usually computed at
from 350 to 500 pounds per square inch. The ultimate compression for transverse
stresses for 1:3:5 concrete has been taken at 2,000 pounds per square inch.
With a factor of 4, this gives a working pressure of 500 pounds per square
inch; but the ultimate stress in a concrete column of plain concrete is
generally less than 2,000 pounds per square inch. Tests of a large number of 12
by 12- inch plain concrete columns showed an ultimate compressive strength of
approximately 1,000 pounds per square inch; but such concrete columns generally
begin to fail by the development of longitudinal cracks. These would be largely
prevented by the use of lateral reinforcement or bands. Therefore the use of
500 pounds per square inch as a working stress for concrete columns which are
properly reinforced may be considered justifiable although not conservative. It
may be demonstrated by theoretical mechanics, that if a load is jointly
supported by two kinds of material with dissimilar elasticity, the proportion
of the loading borne by each will be in a ratio depending on their relative
areas and module of elasticity. The formula for this may be developed as
follows: Example 1: A concrete column is
designed to carry a load of 160,000 pounds. If the concrete column is made 18
inches square, and the load per square inch to be carried by the concrete is
limited to 400 pounds, what must be the ratio of the steel, and how much steel
would be required? Answer. A concrete column 18 inches square has an area of
324 square inches. Dividing 160,000 by 324, we have 494 pounds per square inch
as the total unit compression upon the concrete and the steel, which is C in
the above formula. Assume that the concrete is 1:3:5 concrete, and that the
ratio of the module of elasticity (r) is therefore 12. Substituting these
values in Equation 41, we have: Multiplying this ratio by the total area of the
concrete column, 324 square inches, we have 6.93 square inches of steel
required in the concrete column. This would very nearly be provided by four
bars 1 inch square. Four round bars 11 inches in diameter would give an excess
in area. Either solution would be amply
safe under the circumstances, provided the concrete column was properly
reinforced with bands. A concrete column 16 inches square is subjected to a
load of 115,000 pounds, and is reinforced by four 1-inch square bars besides
the bands. What is the actual compressive stress in the concrete per square
inch? Answer. Dividing the total stress (115,000) by the area (256), we have
the combined unit-stress C = 449 pounds per square inch. By inverting one of
the equations above, we can write: In the above case, the four -i-inch bars have an area of 3.06 square inches; and
therefore, Substituting these values in the above equation, we may write: The
net area of the concrete in the above problem is 252.94 square inches.

**Are You in ****Carver Massachusetts****? Do You
Need Concrete Cutting?**

**We Are Your Local
Concrete Cutter**

**Call ****781-519-2456**

**We Service ****Carver**** MA and all surrounding Cities & Towns**