The Detroit times., 1911-02-20


steel brackets or by concrete brack-
nected 10 concrete core OF columns.
and moulded simultaneously with
Sec is. PROPORTIONS OF M
GKEDiENTs- The concrete for
struction. shall be mixed In proper
land cement 10 two CD parts OF sand
and not more than four co parts OF
either broken stone or gravel
The concrete for columns. shall be
mixed In the proportion OF one %
part Portland cement, one and one
half 1hD parts OF sand and three
CD parts OF broken stone or gravel
In no case shall more than two Cd
parts OF sand be used TO one Cd part
of cement.
An mixing shall be done by machine
n the total amount OF concrete ex-
ceeds nifty 600 cubic yards. ~
The proportions OF the ingredients
must be ascertained by actual meas
urement. Clean water FREQ from
strong acids or alkalis must DO used
In all mixing.
Iron Stag or other similar porous
materials. may be used In place OF
proved by the Department OF Build
ings. and In such cases the Depart
ment OF Buildings may require a
reduction In the proportion Of the
Stag or other similar porous ma
terial In order to have tho voids
ton by volume. OF one Cd part Port
prs See IL e Quality OF MATER
IAEs. tai STEEL all reinforce
ing bars used in reinforced con-
hearth or the Bessemer process.
bars TO be rolled directly from the
original billet. No rerolled steel
will be allowed. The steel shall
conform 10 the following limits In
chemical composition
Phosphorus shall not exceed 10
per cent.
Sulphur shall not exceed .e6 per cent
Manganese shall not exceed so per
cent
Carbon shall not exceed go per cent.
All steel shall conform TO the fol-
lowing physical requirements:
The ultimate tensile strength
shall not be less than sixty thous-
and (60,000) pounds per square
inch OF net cross section.
The yield point shall not be
less than one-half (A) the ulti-
mate strength.
The eions alton per cent. in eight
Ss) inches shall not be less than
modification as follows: For each
increase OF one-eighth tb) inch In
thickness, above three-Quarter( NJ
inches, deduction or one CD per
cent; for each decrease of one-six-
teenth u-l6) inch In thickness, be-
low five-sixteenths (6-16) inch, q
deduction OF two and one-half
(21a) per cent.
Test specimens for bending shall
be bent cold around diameter
equal TO their least thickness, to
tho following angles without frae-
ture on the outside OF the bent por-
ton;
For specimens one CD inch thick.
80 degrees.
For specimens three-quarter (&)
inch thick. 30 degrees.
For specimens one-half (h) inch
thick. ITO degrees
For specimens one-Quarter (A)
inch thick. 1870 degrees.
(s-16j inch thick. l4o degrees
For specimens one-eighth (h)
inch thick. 160 degrees.
OBJ CEMENT. The Portland
dard specifications of the American
Society for Testing Materials. In
force Dec. 1. 1910. except that the
minimum requirements for tensile
strength shall be as noted In SEQ
ton 20 OF this articie.
(c) SAND. The sand shall be
clean. free from any organic mat
ter and graded from coarse to me.
(d) STONE. GRAVEL OR STAG.
The stone shall be clean crushed
stone, free from dirt or dust and
The gravel shall be washed
The Stag shall be clean crushed
blast furnace Stag.
All aggregate must be or sucn
size as will pass through a three
quarter (A) inch screen and be re-
tanned on one-duarter Sh) incn
screen. ~ 80 -
See. is. MATERIALS pRoHIE-
TIED. The following materials
shsd 1S BE usiS IN sosr sa
plaster OF paris. sulphate OF lime
and ALI similar injurious materials.
Sec. 1s. CENTERINq AND
All forms shall .be. built strong.
unyielding, plumb and true, thor
oughiy braced and with tight
joints, so that no appreciable part
OF the concrete mixture can escape,
and they shall be supported to
carry all OF the usual loads which
may come upon them without
spring or DETECTION.
For columns an opening shall be
left at the bottom OF the form. for
cleaning and adjusting the steel;
The opening shall not be closed
until the column Is to be poured
Columns over fourteen (1G feet
inches square, shall have an inter
mediate opening or pocket ana the
pouring started therefrom. The
forms shall be thoroughly cleaned
poured, and all chips, Ice and other
foreign matters removed.
Before removing the shores un-
der any beam or girder, the column
supporting IT shall be stripped. SO
that the column may be examined
on nil sides
III ample shores are used TO carry
the full weight OF the floor. column
forms may be removed as soon as
the concrete has set up hard, pro-
be removed within seventy-two (72)
hours after pouring.
The sides OF girder and beam
forms, may be removed at the ex-
piration or six t6) days AFTER pour
The time which must elapse be-
fore removing the shores under the
girders and beams, Will vary with
the design and the condluons or
the weather. but in no case shall
they be removed in less than three
(3) weeks after pouring.
The supports under hoor slabs
shall not be removed In less time
than ten t1O days after pouring,
but this clause Is not intended to
prevent removing the toists and
tagging within a less time, provid-
ed the slabs are kept properly
shored up.
Sec III. PLACING OF REIN
FORCEMENTS. All reinforcing
members shall be accurately locat-
ed in the forms and secured firmly
against displacement. They shall
have a protection OF concrete, not
less than two 90 inches thick for
columns, one and one-half q Il
inches thick on the bottom and
side OF Orders and beams and
three quarters (A) inch on bottom
of floor slabs.
The amount OF concrete protec-
tion shall be clear OF the reinforce
ing members.
Exposed metal centering or ex-
posed metal OF any kind. shall not
be considered a factor In the