swe B Oph.

UTILITY AND ECONOMY
atts
Dil miele mee ere
DWELLING HOUSE
For Degree oF C. E,
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The Utility and Economy of the Reinforced
Concrete Dwelling House.
Thesis

For
The Degree of Civil Engineer
at
The Michigan Agricultural College

1913

by fw

eS

Maurice ¥-Jongeon.
THESIS
The Utility and Economy of the Reinforced

Concrete Dwelling House.

The object of this thesis, is, as the title implies,
to show the adaptability of reinforced concrete to modern
dwelling house construction, to show some of the methods of
designing and constructing, and to give a comparison of the cost
of this with other house building materials.

Many of the so-called concrete houses have concrete
side walls with roof, partitions and floors entirely of wood.
Such buildings have few advantages over the frame structure
and should not be classified as a reinforced concrete dwelling.

Experience and tests show that reinforced concrete
is particularly well adapted to all kinds of construction. It
is used for foundations, walls, columns, beams, floors, and for
nearly every detail of construction. It is not only strong
and durable but its plasticity lends it to ornamental purposes
as well. It becomes harder with age, never decays, does not
need repairs and be made water proof, and is practically fire
proof. At present it seems to be the practical building material
for nearly every requirement of building construction. It has a
larger range of possibilities than any other building material.
Materials for its construction are available in nearly every
locality, and the fact that it can be cast into nearly every con-
ceivable shape right on the job makes it a building material of
many advantages.

For many years men have becn making a study of the
best and most economical house building material to secure permansn-

cy, durability, and comtor hoagie materials have been tried
With more or less satisfactory results but most of our house
construction up to the present time has been more or less of
the mushroom order and easily destroyed by fire and elements.
Concrete, however, comes nearer the solution of the problem
than any other material. When properly mixed and handled it
should stand for hundreds of years and with each succeeding
year it forms a more perfect bond the better to withstand fire,
floods, earthquakes, and all conditions of the weather. Con-
crete is a nonconductor of heet, therefore houses built of

this material will be warmer in the winter and cooler in the
Summer. They are also vermin proof and if properly built they
come the nearest to being germ and dust proof, which should be
no small item in deciding on a material for house construction.
The initial cost of these houses leads one to believe that they
are not the most economical. In some cases they are not, perhaps.
In building houses to sell, a larger percent of profit would
probably be rezlized from a wooden frame structure than from
concrete. Where permanency is desired, however, there are
several things to consider in determining the most economical
material. Fire insurance, repairs, and painting should be
notning at ell in a concrete dwelling, which in a few years
would more than offset the actual difference in first cost.
Besides this the safety of such a structure sgseinst all sorts
of emergencies to ones family, furniture and valuables is a big
item in its favor. There are very few, if any, disadvantages

to be overcome in the use of concrete for house construction,

unless perhaps it is the difficulty of securing competent and
experienced workmen, which is an item that should not be over-
looked. When considered from all viewpoints, however, concrete
seems to be the nearest to the ideal house building material.

Time alone can decide the style of architecture that
will prevail. Concrete adapts itself to any form of plastic
design and lends itself to almost every conceivable style.
The more modest houses will undoubtedly follow the straight
line patterns with few exterior decorations, except for vines,
shrubs, etc., which lend a great deal to the beauty of concrete
houses that might otherwise be plain and unattractive.

There is a wide range of possibilities in tne finishimg
of outside walls. Surfacing may be carried on by the use of a
false partition of sheet steel held in place an inch away from
the rough wall,and the space between filled with the finishing
mixture. This operation is carried on at the same time that
the wall is being constructed. By removing the partition before
the wall sets the facing mixture adheres to the wall. The same
results may be obtained by spading the concrete back from the
front of the forms and introducing the finishing material which
at once unttes with the wall. These finishing mixtures, usually
a l to 2 mixture, may be a plain or colored cement mortar or
composed of cement and aggregates of broken stones, brick, or
gravel, depending on the color and texture desired. After the
forms are removed the joint marks and impressions of the grain
of the wood will be retained on the wall. These disfigurenents
must be removed before an acceptable finish is obtained. This
may be accomplished in different ways. The outer film of cement

~3e
is scrubbed or brusned from the surface exposing some of the
agsregate and leaving a very pleasing surface. This scrubbing
or brusning must be undertaken within twenty-four hours of the
time the concrete is poured into the forms, and while the con-
crete is still green. For this reason the walls cannot be
carried to any considerable height at one operation and the
forms must be so arranged that they can be readily removed. If
for any reason the forms cannot be removed before the concrete
is set and too hard to surface by scrubbing or brushing with a
wire brush, some method of tooling the surface may be employed.
Hammering, picking, and sand blasting are used to good effect.
These methods require care and experience in using them. The
ageresate inay be disturbed by hammering or picking, while the
sand blast will cut too deep in soft spots and not deep enough
where the surface is harder, thus weakening the walls.

If the walls are to be surfaced by scrubbing it is
customery to pour about two feet of concrete at a time, removing
the forms as soon as the concrete is stiff enough to stand alone.

Tne surfacing mixtures may vary in color from white,
obtained by the use of white cement, to several shades of gray
and slate, obtained by the use of coloring mixed as follows:-
The ingredients should be mixed with the cement while dry.

(Any concrete excepting that colored by crushed rock will fade
with age.)

In the following table the mortar is ge 1 to 2 mixture:-
Material +# per 10O# Cement 44 per 100# Cement

Lamp Black Light slate Dark Blue Slate
Prussian Blue Light green slate Bright blue slate
Ultra Marine Blue Bright blue slate
Yellow Ocher Lignt green Light buff

Burnt Umber Light pinkish slate Chocolate
Venetian Red Slate, pink tinge Dull pink

Red Iron Ore Pinkish slate Light brick red.

A concrete made of granite screenings and mixed
comparatively dry gives a good mortar to be used in the above
mentioned metnod of surfacing.

Stucco may be applied directly to the concrete in sur-
facing the outer walls. In order to secure an even color, if
coloring is used, a large amount should be mixed dry and water
added to such quantities as will be immediately needed. This
prevents unevenness of color caused by mixing small batches.
Surfaces that are floated or troweled may show slight variations
in color due to differences in troweling. Freezing will change
the color of stucco, as will sunlight and cloudy wet weatner.
Stucco should not be applied in freezing weather. If the water
freezes before the cement has set the stucco will not harden.

Stucco is not the most economicel surfacing for concrete
walls, as much the same effects may be obtained from other
methods wnich require less time and material and are more durable.

The roof of a concrete house should be flat. The

pitching of residence roofs at a steep angle was originally to

~Aa
make a shingle roof rain proof. Considering the preponderence
of the shingle roofs over those of any other material it is

not surprising that the pitched roof should become our standard.
The concrete slab roof does not require such construction. It
should be pitched enough to carry off the rain and if necessary
add a parapet or other architectural features. This will make
it possible to use the roof much as our porches are now used.
Such a roof would not be feasible with timber, but with concrete
it is simple and most economical.

The concrete house, whether it has block or monolithic
walls should have, not only the reinforced roof, but reinforced
walls and stairs as well, and these without the wooden surface.
Such construction adds to the fire proof qualities of the house
and is cleaner and more sanitary. By removing the rugs the
house may be flushed out with the hose, removing the dirt more
easily tnan in any otner way.

Concrete conveys the sound quite readily, so if the floors
are to be used without rugs over them it is better to construct
the floor by combining the concrete with hollow tile. The hollow
tile are laid in rows about four inches apart and in the space
between are built reinforced concrete beams. A layer of concrete
is then placed over the entire surface. If a wood floor is desired
wooden sleepers are embedded in the top layer of concrete to
which the flooring is nailed.

For interior non-supporting walls, plastering over metal

lath is probably one of the most economical methods of construction ;
Companies manufacturing the metal lath also make a metal studding
to be used with it so no wood need enter into the construction.
Two rough and heavy coats of plaster, followed by a coat of hard
plaster, makes a very good partition.

The expanded metal is also used in floor and roof con-
struction but it is not as well adapted to stress analysis as
some other methods.

The metal lath may also be used for outer wall construc.
tion, but it is generally so used in connection with wooden floors
and a semi fire proof construction.

To overcome the cost of constructing forms for concrete
beams and floor slabs, a metnod of casting these structural men-
bers in standard sizes has been devised. Concrete floor joists.
and slabs are made and delivered by the manufacturer and set and
finisned by the builder. <After the joists are set in place the
ceiling slabs are laid on the lower bevelled flanges and the
joints filled with cement mortar. The floor slab is then placed
on the top flanges. In many localities, however, the expense of
delivering such members would be greater than the cost of building
them on the job. When the slabs and beams are poured in position,
wood forms are generally used. Steel forms are obtainable for
such work but they are more economical where they can be taken
down and used several times. The forms for floor slabs and beams
must stay in place until the concrete is thoroughly set,and in
many cases it would be desirable to build the forms and pour the
second floor before the first floor had set sufficiently to carry
the necessary load.

= Ta
Concrete roofs are designed and laid in much the same
manner as the floors. The forms are also very similar. In
order to obtain a reasonably light roof, cinder concrete is
often used. The roof may be made water proof by the use of a
layer of rich concrete troweled to a smooth finisn. The roof
must, not contain joints and must be finished by expert workrien.
It is generally advisable, however, to cover the concrete roof
witn some water proofing material, as tar and gravel.

Concrete stairs may be built very conveniently with
side girders wnich may be calculated as a beam with a longitudi-
nal rod near the lower surface. <A small rod should run from
girder to girder near the foot of each riser so that each riser
acts as a reinforced beam. If the stairs are very wide, one or
two girders may be placed between the side girders to support
the stairs in the middle.

There are various ways of constructing concrete walls.
If concrete could be laid in thin walls as cheaply es in massa
work it would be the least expensive material for permanent cone
struction. The nrinciple item of expense is the construction of
forms,and tnis has led to the invention of several methods of
constructing thin walls.

The expense of building wooden forms to pour an entire
wall at once is very great as compared to the amount of concrete
to be placed in thin walls. Such construction also requires
more expensive surfacing as the wall becomes hard before the
forms may be removed. This method of form construction was
designed for mass work and is not necessary in thin walls.

-8-
Portable forms are easily constructed to a height of about two
or three feet and these may be raised with each layer of concrete.
Such forms shou]d be removed as soon as the concrete will sustain
its own weight in order to allow surfacing while the concrete is
still green. It is generally desirable to employ help enough to
place a layer of concrete each day so the forms may be raised
each morning.

For details of vortable wooden forms see drawing No.10

Studding for wood forms should not be placed more than
four feet apart and the sheeting used for the lining of the
forms should be two inch planks dressed on one side. The forms
should be thoroughly braced so they will be perfectly rigid
during the operations of pouring and tamping the concrete.

Steel forms have been used for mass concrete and other
engineering construction to some extent for several years. The
application of these forms to house construction, however, has
come quite slowly. These forms have many advantages over wooden
forms, and, as the concrete house construction becomes more
common, they will probably replace the wooden forms entirely.

These forms are constructed in panels of various sizes
and must be designed to fit each different wall. There are
especially designed lap corner panels, for inside corners,
outside corner angles, special liners, ties and fasteners, all
of which must be ordered special for any job. Enough forms are
generally purchased to allow for a three or four foot layer of
concrete entirely around the building and across each of the

sustaining walls.
These forms are perfectly rigid and leave a smooth
wall which requires no surfacing. They do not warp nor change
their shape easily and may be used many times if properly
cleaned and handled. Each job, however, would generally
require a few special panels or pieces in order to do good
work.

Steel forms complete with liner braces, etc., cost
approximately forty-five cents per square foot of form surface,
f.o. bd. If they are owned by a contractor who could use them
several times in a season the cost would not be excessive. The
same forms may be loaned from the manufacturers for 30¢ per
square foot of form surface, but even at that price would be
too expensive for most work if they were to be used for only
One building.

Another system of erecting side walls is known as the
Aiken system. It is being used some by the U. S. government
and its principle features are as follows: Foundation walls
are first built to a level of the first floor, a platform is
then built resting on jacks in the basement excavation and the
front wall cast upon the platform. Door and window casings
are put in place on the platform so when the wall is completed
and raised to a vertical position they are ready for the inser-
tion of the doors and windows. The surface finish may be
obtained before the wall is raised. The wall being flat allows
the workmen to operate from a bridge and in that way most any
desired finish may be obtained. This also gives great opportu-
nities for decorations which could not otherwise be obtained.

After the front wall is anchored in position the rear wall is

-~10-
cast and raised in a similar manner, requiring merely another
setting of the jacks beneath the platform. The side walls are
made short enough to be raised from the inside between the two
walls already in position. After the walls are all raised
forms are placed and the corners poured.

Double walls are cast in this way by covering the
first layer of concrete with a layer of dry sand. The outer
wall is cast upon the sand and anchored to the inner wall. The
sand is rodded out before the wall is raised to its final
position.

The desired air space may be obtained in these walls
by laying hollow tile on the platform and casting the outer
wall on this and then plastering over the tile after the wall
is in position.

These jacks are raised simultaneously by power, being
connected by a tumbling rod. By the aid of these jacks the
wall rotates about the rod or shaft as an axis and being very
nearly balanced does not require very much power.

For house construction the machinery complete costs
approximately $16.00 per linear foot of the longest wall to
be raised, besides this a small gasoline engine would be
required to furnish the power.

This system could be used economically only by con-
tractors or companies where they had several jobs of construc-
tion on which the machines could be used.

Another system of wall construction is known as
The VanGuilder System. The system consists of a hollow wall

machine which is placed, filled with concrete, and tamped.

wttl.
The machine is then released from the concrete by the means of
a lever and moved along. It is similar to the construction of
concrete blocks except that they are in position when moulded.
This system is generally used with wooden floors and roofs

and the walls are generelly not reinforced. It is advertised,
however, as being a fire proof construction, which is true
only of the outer walls.

Owing to its great density concrete does not readily
receive nails or screws, and any cutting or drilling can be
done only with great difficulty and considerable expense. For
this reason plans should indicate the location of plumbing
and heating pipes, electric conduits, etc., as well as the
position of any wood trimmings, so that all holes and blocks
may be provided for during the construction of the building.

Window and door frames in position when walls are
poured must be thoroughly braced so that they will not be
warped when the concrete is tamped.

There are many and varied weys of decorating the
exterior of monolithic concrete houses. The Old English
panelled effect is obtained by planing furring strips in the
concrete and to these are nailed the panel strips. When these
strips are painted the color is slightly reflected by the
concrete surface in such a way as to give a tinge to the sure
face which is very pleasing.

Flower baskets are often built into the walls of
houses, or along the top of the parapet walls and in warm
weather the vines and flowers give some very beautiful effects.

Wrought iron lends itself very beautifully in decorating
~19
concrete houses end is used considerably. It is often used in
the form of window and door grilles where iron contrasts well
With a wall of almost any color and texture. Wrought iron
receptacles fashioned to receive and hold flower boxes are
particularly pleasing, and when employed for window balconies
combine nicely with casement windows.

It is believed by some that concrete can not be used
economically in house construction unless the owner intends
to spend from $20,000.00 to $25,000.00. This is not true,
however, as houses have been constructed of’concrete et a much
more reasonable figure.

In order to show some of the methods of designing a
concrete house, I shall present here the drawings together
with the formulas for designing the members of a medium sized
house. I shall also give approximately the cost of such a
structure. |

A close approximation to the cost of a building can
not be given for all localities, owing to the fact that the cost
of labor and materials vary greatly in the different localities.

The outer walls will be reinforced and hollow. The
‘inner supporting wall will be a 7" wall with wooden strips
embedded vertically 2 ft. on centers to which one inch furring
strips are railed, lathed and plastered for finished surface.
The floors, beams, columns, stsirs and roof of reinforced con-
crete. Doors, door and window casings of wood.

The minimum live load for which floors should be
designed is 30 pounds per square foot of floor area. The maxi-
mum need not exceed l00# per square foot. In the following the

-13
maximum load will be considered:

The cellar wall 10 inches thick, the concrete should be
mixed in the proportions of 1:24:5. Por beams, girders, walls
and floors, the mixture should be 1:2:4.

In the following, formulas will be given for the
design of floor slabs, beams, etc., which will be used in the
design of the parts of the accompanying house drawings.

"The straight line theory" will be used because it is
most ecsily understood and is the simplest method of design.
This theory assumes the following hypothesis as a basis of
design. (See Taylor & Thompson's Concrete, Plain and Reinforced)

1. A plane section before the bending remains plane after
bending.

2. Tension is borne entirely by the steel.

3. Initial tersion or compression is absent in the steel.

4. Adhesion of concrete to steel is perfect within working —
limits.

5. Modulus of elasticity of concrete within the usual limits

of stress is constant.

Further reasons for the use of this theory are as
follows:
(a)Beams designed by it and properly built will be unques-
tionably safe.
(b)FPine cracks are formed in the tension portion of the
beam at an early stage in the loading which actually

destroy nearly all of the tensil resistance of the concreté

(c)The modulus of elasticity in many tests has been shown

~14-
to be approximately a constant within working loads.
(ad) This theory has been adopted by the highest suthorities
in America and Europe.
(e) The results from it may be readily compared with other

theories.

The following formulas are used with these essumptions:

Design of a Rectangular Beam.

 

 

 

 

 

 

 

 

£4 _ f= 4 —
KK kh
Ss 8.
,
4x
3 Nb
Neutral Axia | 4 |_y_|__
‘Nh
8
& Stee/._ =H - - fF —-—_ -_ - yi — -@——

 

 

 

 

 

In a simple rectangular beam the stresses may be
represented ss in the above diagram. In any vertical section
the upper portion of the concrete resists the forces which tend
to compress it,while the steel in the lower part resists the
forces which tend to stretch and break it in tension.

-15-
The safe resisting moment of the beam must be equal

to or greater than the bending moment. This resisting moment

is equal to the product of the moment arm (distance between

centers of compression and tension) times either the total safe

pressure or total safe pull. The minimum valve of resisting

moment must be considered.

Jd

As

M

st

In the following let

depth of beam from compressed surface to center of
steel in inches.

moment arm or distance between centers of tension end
compression.

breadth of beam.

ratio of cross section of steel to cross section of
beam above the center of gravity of the steel.

area of cross section of steel in sq. in.

moment of resistance or bending moment, in general in
inch pounds.

a constant for a given steel and a given concrete.

650 lbs. per sq. in. will be used for a working

compression in concrete and 16,000 lbs. per sq. in a working pull

in steel.

The ratio of the modulus of steel to concrete of 15

will be used.

Using the above we nave the following formulas;

1.
d = 10 b

 

-~1l6~-
In using the above the bending moment is calculated
for the required loads, b is assumed, and from this ad and
As are calculated.

These formulas will be used in calculding the depth of
the floor slabs. A section will be taken transverse to the
floor beams 12 inches wide.

( For floor and celling
Design of slab 8'-4" long )
, ( of living room.
Agsumed dead load 50# per sq. ft.
" live “" loo# " " *

M moment
W # load per running foot
1 - length of beam.

b * breadth e 12"

wl

12) ~=Slw «36180 X 81/3 XB 1/3 X12 - 10350 inch
12 pounds.

Mi

 

10350
29

As = .0oO77 X 3 X 12 = .28
Allowing # inches of concrete to cover steel

hs 3 3/4 inches.

-l17~-
Use one round rod 5/8" diameter. 3/4" from bottom.

tt 1 short " " 4 ft. long 3/4" from

surface to take negative moment over beams.

For slab 6 ft. long for kitchen end floor above and roof.

Loeds as above.

wi< 150 X 6 X 6 X 12
Me Lo = LD 2 9400 in pounds

1
d =I0 = 12 = 2+ inches.

As = .0077 xX 12 x 24 = .20

Use he 3"

" lrod 9/16" diameter. 3/4" from bottom
Also one short rod (4'-0") 9/16" in diameter 3/4" from

top to lap over support, and take tension due to negative moment.

For slab 8'!06" long. Diningroom floor and floor above.

 

 

1 # gt.6"
ye «WIS 5 150 X 8.5 X 8.5 X 12 . 10,800 inch pounds
12 Le
10 800
a = Z 2 jt

allowing 3/4" to cover steel h 3 3/4"

As #® .0077 X 3 X 12 = .28
use one rod 5/8" diameter

Insert short one same size near surface over suppors.

-18-
Roof slab 9' - O" span above dining room.

 

wl 150 X 9Q x 9 x Lé
Mose 12 : le | - 120,000
L 1Z000_|
C = LO = 12 = 3. 1

cllowins 3/4" for e h- 3 3/4"

AS = O77 X 3 X 12 28

Use 1 rod 5/8" in diameter.

Insert snort one over sunport near top.

Beceuse of embedding metal, concrete floors should be
limnited to « thickness of 3".

Concrete for floors and beams should be rixed wet enough
so the mortar will flow around the metal and entirely coat and
protect it from rust end fire. It should be wet enough so if
not handled quickly it will run off the shovel.

Floor forms should be so designed thet they may be eesily
removed and used a second time where possible.

Beams and small colum forms mzy be held by clamps thus
avoiding naoiling them.

Forms for floor beams snd slabs should not be removed for
at lesst one veek ond should generally be left in place for

two or three weeks if the floor is to be subjected to any load.
Design of T Beam.

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

F .
_ | Center ofc 7
a ee Canter Compression _ Tf eT TT ~[--
y
— ty
* %
Vv y
eee —_
Vv
<_—__ 6 —_——_—_>

 

 

When beam and slab are built at tne same time so
there is no crack between them, a portion of the slab may be
considered as acting with the upper portion of the beam in
compression. In this way the quantity of concrete necessary
for safety may be very much reduced.

The theory of design is similar to that of the rectan-
gular bean, tnet is, the unner portion takes the compression
and tne lower portion takes tne tension.

In the design of a T beam the tnicxness of the
flange is determined by the thickness of slab required to

a2Ne-
to support its load and the width of flange to use is selected
in accordance with empirical rules. The width is limited on
either side to four times the depth of the slab, for heavy work,
for house construction, however, this ratio might be slightly
increased and still be within safe limits.

In the following let
ds depth of T beam from compressed surface to center of

steel in inches

t #« thickness of flange in inches

b » breadth of stem in inches

t

d- 2 + moment arm, the depth from center of slab to steel.
VY ss total vertical shear
iM. bending moment in inch pounds

Fs 2 allowable unit tension in steel in pounds per sq. inch.

r = ratio of unit cost of steel in place to unit cost of
concrete in place.
AS 2 cross section of steel in square inches.

Using the given notation the following formula determines
the cross section of the web for shear.
b! (ae ET 0
(120 - Max. allowable unit shear)
Formula for determining the economical depth of a T beam
(4B) se
In using this formula different widths are assumed and

d
d calculated. (The ratio of b should never be less than 2.

~2l-
Formula for determining sectional area of steel ina

TT beam
M

As » Fs (ad - * )
2
In solid concrete beams horizontal shear need not be

considered.

Design of T Beam for ceiling of living room to support
wall above.

Span 16' - 3"

Distance between beams 8! - 4" C to C.

Live locd 150; per sq. ft.

Assuned dead lo.d 50}/ per sq. ft.

" " " of beam 2CC# per ft.
Total logd ver running foot of beam, 2200;

Using same notation as in preceding work.

 

 

wi 2200 X 16.25 XK 16.25 xX 12 . 560,000
If = Le = Le

Reaction at supports = V = 17,500.

To find breadth of flanse take 8 times the thickness of
slab nlus breadth of stem of beam (assumed 10 inches).
b =(8 X 4) 10 = 42 in.
febt 2650 X 42 X 4 -# 109 200
Assumed ratio — . 3
Using these valves with table on nase 225 of Taylor and

Thomson's Reinforced concrete the minimum depth is 10 inches.

oo)

enw
Using formula for most economical depth.
~ rv
(d= 2 =f fsb!
Using re 70
Ki = 560,000
fs = 16,000
bt = 10"

t2 32"

t 70 X 560,000

(d - 2 *~ “i6,000 xX 10

 

d = 16; "

Cross section deternined by shear.
t 17, 500

bi(a-D = YSo. =~ Teo * 148
d - 163"

make e 1" (covering for steel)

h 2 1730

M
Sectioned area of steel AS = fa(i~t-)

560 , OOO
- 16,000 X 154 - 23

Use 4 rods 7/8" in diameter two bent up to lup over
top of support.

In a continuous beam the negative moment over posts is
the same as the vnositive moment <t the middle. The allowable
compression of concrete at the support may be 17% greater than

at the middle.

-25-
Short T beams for floor of living roon.
Span 8' - 2"

Dead plus live load per running foot 1660 lbs.
1660 X82 X 8.2 X 12

 

 

Mos 12 - 107,000 inch pounds.
Min. depth as per above, for b #- 8", is 5".

1660 X 8.2
Ve co = 6200.

Cross section determined by shear With b= 8"
t 6200
b'(d- 2 ) 2 120 - 51.7
d= 84"

allowing e- 1" to cover steel.

 

hs 93%
M 107000 _.
As = fs(d --L - 16000 (6%) = 1.03
2
13 i]
Use 2 16 diameter rods.

Use two short ones same size and bent down over support

for negative moment.

Diningroom floor beams.
l= 6! - 6"
Total load per ft 1550 lbs.

wi” = 1350 X 6.5 X6.5 X12 _
Ms 12 Tz = 57000 inch pounds

 

Economical depth = 52 inches

Cross section by shear
1550 X 6.5

Ve 2 4370
t 4370

Wnen b= gB"
d= 63"

allowing 1" for @ to cover steel

h = 40"
Mo 57000 _
AS = f's( d-. £) = 16 OOO xX 4.5 zs
<

 

Use 2 rods * in diameter.

Insert on short one over support.

Dining room ceiling beams and roof above.

Span 13' - 0".

Distance between beams 8! - 6*

Deed plus live loads per running ft. of beam is

8.5 xX 150 = 1275
Assumed dead load of stem 175#

Total load 14507 per ft.

 

 

wie 14450 x13" x12 |
Ms. le - 12 = 245 000 inch pounds
1450 X13
Reaction at support = V = 2 = 9420

Breadth of flange = (8 X 4) 10 = 42"
Min. depth from table = 7"

Cross section determined by shear.

V - 9420

t 9420
b'(d -2) -"130. = 78.
Using b = 10" . te 33"
d=: 92

allowing 1" to cover steel

c
h = loz"

IM 245,000 __
A8S = fs(d-Z) - 16,000 xX 7.75 - 1.95"
9 =

 

Use 2 rods 7/8" diameter
and 2 Ww 3/4" "

Kitchen floor beems -lso same for one above

Span - 6' = 6"
distance between veams 5! -9"

Total loud - 362#. (loads assumed as above)

 

 

wi 862 X 6.5 X 6.5 X 12
a a 12 = 36,400 inch
nounds.
862 X 6.5
Ve oO = 2800
b= (8X3) 6» 30"

Using bt 26"

By shear
b'i(d- 2 ) - TKO - 23.3

 

ad - 54"
Witn e-; 1"
nse 63"
Mt 36,400 2 +955
AW «a fs(d.i. ) - 16,000 X 4
2

Use 2 rods 5/8" diameter.

One short one near surface over support.
AA
Columns of short length as shown in the accompanying
drawings need not be reinforced. The columns in the walls
should be reinforced with a rod in each corner. In the
monolitnic construction a part of the adjacent wall acts with
the column in sustaining the loads,and for house construction

columns need not generally be thicker than the wall itself.
The following will show approximately the cost of such a
structure as is herein shown. Wooden forms and portable will be

considered for the walls.

 

bxcavating 150 yds. @ 30¢ $45 .00
Grading 15.00

$60 .00
Forms

< inch planks for floor forms, stairs, studding

facing of wall forms and runways

 

 

8000 ft. © $20.00 per 160 .0O

2X 4 for studding and bracing, 1000 ft.@ $20.00 20 .00
1x6 " J" for portable forms

Mixing boards, etce., 1500 ft. @ $18.00 27.00
Nails, bolts, etc., for forms . 15.00
Construction and raising forms, runways, etc. 500 .00

$522 .00
Concrete
Floors, cellar, columns, and roof 58 cu. yds.
Inner walls and stairs 25 " "
Cellar walls and floors 38 " "
Outer walls (2" air space) 47 " "
Porch complete 9D " "
Pantry and roof and parapet lt "
Fire place, chimney & parapet 144 "
Total 169 cu. yds.

Allowing materials for a 1:2:4 mixture the concrete

would cost as follows:

283
265 bus. cement G $1.60 $424
75 yds. sand «2 90 37
1so.) Oo" gravel or stone (¢.80 120

Mixing and placing concrete

169 yds. G $3.50 591

Steel in place @ 3¢g per pound

2900 ft. 5/8" round 30254 G 3¢ 90
825 " 3/4" " 1240" © 3¢ 37
2210 " 1/2" 1470" © 3¢ 43
360 " 9/10" " 305" © 3¢ 9

Plastering including materials and labor @ 357

610 sq. yds. & 35¢ 2135
Metal lath 106 yds. & $3.00 318
Finisning outer surface 50

Doors and windows complete in place

OO
90
00

$581.00

50 091.50

75
220
~ LO

15
180 .20

50 215.50
-00 518.00
00 00 .00

~O0 500 .00
-00 L000 .00

£00 100 .00__

 

including frames 200
Plumbing and heating 1000
Wiring and light fixtures LOO

Total

Allowing 10% for profit

$4176 .20

417.60
4593.80
Inexperienced labor and variations in the cost of
materials and labor would cause a variation of several hundred
dollars. Such a house could, under ordinary conditions, be
built well within the limit given.

The cost of tne same house built by the usual methods
of frame construction would depend very lergely on the materials
and finish desired. Such a house built as the average man could
afford would come within the $3000.00 limit.

The best autnorities claim that a house built of concrete
throughout costs from 15 to 50 per cent, more than a similarly
designed frame house. This theory is shown to be true by houses
that have actually been constructed.

When the demand for the concrete house is sufficient to
warrant contractors a reasonable amount of work in this line,
they will undoubtedly supply themselves with steel forms or other
patent devices for wall construction and the initial cost of
these dwellings will be greatly reduced.

A complete set of steel forms for the house shown in the
drawings would cost @ 45¢ per sq. ft. of form about $515.00. The
same forms could be rented for $345.00. Not including freight
in either case.

Machinery necessary for the construction of the same

house by the Aiken system would cost sas follows:

5 Pony Jacks @ $90.00 $450 .00
50 ft. Hexigon Shafting © 20¢ 6 .00
1 Main Drive Head 20.00 |

 

Total $476. 00

This does not include the rent of the engine for power

=“J0-
in raising walls.

The VanGuilder Hollow Wall concrete machines and

attachments for the house shown would cost approximately $300 .00

Clippings are srown in the following pages of the above
patent wall devices, in use:

Also of houses constructed of concrete throughout and
from which it can be seen that concrete is being used for the
Cheap or laboring man's cottage as well as the better class of

nouses.
 

 

 

The cuts show the Aiken System of raising walls.
=5o
 

 

The above cut shows the steel forms in use for

a house foundation.
 

The above cut shows factory employees’ cottages erected
at Racine, Wis.

-34-
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