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 New Hampshire Concrete Cutting 210 Walnut St, Manchester, NH 03104 Call Now 603-622-4440 Concrete Cutting - Core Drilling - Wall Sawing - Flat Sawing |
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Concrete Cutting Sawing Peterborough NH New HampshireWelcome
to affordableconcretecutters.net
“We
Specialize in Cutting Doorways and Windows in Concrete Foundations”
Are You in Peterborough New
Hampshire? Do You Need Concrete Cutting?
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Concrete Cutter
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NH and all surrounding Cities & Towns
“No Travel Charges – Ever! Guaranteed!”
A Trip To Peterborough, New Hampshire - An Ideal Getaway For Holidays As
fast as the bars can be spared from the bottom of the concrete beam, they may
be turned up diagonally so that there are at every section of the concrete beam
one or more bars which would be cut diagonally by such a section. On this
account it is far better to use a larger number of bars, than a smaller number
of the same area. For example, if it were required that there shall be 2.25
square inches of steel for the section at the middle of the concrete beam, it
would be far better to use nine k-inch bars than four 1-inch bars. In either
case, the steel has the 72 = 73,152 pounds. So far as its effect on moment is
concerned, the concentrated load of 2,400 pounds at the center would have the
same effect as 4,800 pounds uniformly distributed. As it is a piece of
vibrating machinery, we shall use a factor of six (6), and thus have an
ultimate effect of 6 X 4,800 = 28,800 pounds. Adding this to 73,152, we have
101,952 pounds as the equivalent, ultimate, uniformly distributed had. Then, M.
= - W. 1 x 101,952 x 216.
2,752,704. In order to reduce as much as possible the size and weight of this concrete
beam, we shall use 1: 2: 4 concrete, and therefore apply Equation 24: 2,752,704
& 565bd'; bd' = 4,872. If b = 16 inches, d2 =
304.5, and d = 17.5 inches. A still better combination would be a deeper and
narrower concrete beam with b = 12 inches, and d = 20.15 inches. With this
combination, the required area of the steel will equal: A = .0121 X bd = .0121 x 12 x 20.15 2.93 square inches. This can be
supplied by eight bars - inch square. The total ultimate load as determined
above is 101,952 pounds. One-half of this gives the maximum shear at the ends,
or 50,976 pounds. Applying Equation 31, we have, since d - x = .85 d = 17
inches: V 50,796 = b (d—x) = 12 >< 17
= 249 pounds per square inch. As already discussed in previous cases, the ends
of the concrete beam must be reinforced against diagonal tension, since the
above value of v is too great, even as an ultimate value, for such stress.
Therefore the ends of the concrete beam must be reinforced by turning the bars
up, or by the use of stirrups. The concrete beam must therefore be reinforced
about as shown in Fig. 102. Although the concentrated center load in this case
is comparatively too small to require any change in the design, it should not
be forgotten that a concentrated load may cause the shear to change so rapidly
that it might require special provision for it by means of stirrups in the
center of the concrete beam, where there is ordinarily no reinforcement which will
assist shearing stresses. There is one very radical difference between the
behavior of a concrete-steel concrete structure and that of a concrete
structure composed entirely of steel, such as a truss bridge. A truss bridge
may be overloaded with a load which momentarily passes the elastic limit, and
yet the bridge will not necessarily fail, and not cause the truss to be so
injured that it is useless and must be immediately replaced. The truss might
sag a little, but no immediate failure is imminent. On this account, the factor
of safety on truss bridges is usually computed on the basis of the ultimate
strength. A concrete steel concrete structure acts very differently. As has
already been explained, the intimate union of the concrete and the steel at all
points along the length of the bar (and not merely at the ends), is an absolute
essential for stability. If the elastic limit of the steel has been exceeded
owing to an overload, then the union between the concrete and the steel has
unquestionably been destroyed, provided that union depends on mere adhesion.
Even if that union is assisted by a mechanical bond, the distortion of the
steel has broken that bond to some extent, although it will still require a
very considerable force to pull the bar through the concrete. I
Are You in Peterborough New
Hampshire? Do You Need Concrete Cutting?
We Are Your Local
Concrete Cutter
Call 603-622-4440
We Service Peterborough
NH and all surrounding Cities & Towns
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