The Detroit times. [volume] (Detroit, Mich.) 1903-1920, 1911-02-21

cts. properly reinforced. and con-
nectod 20 concreto core Of columns.
and moulded simultaneously with
Sec. Is. PROPORTIONS on M
walls. beams girders and moor con-
struction. shall be mixed In proper
land cement 10 two CD parts OF sand
and not more than four "a parts OF
either broken stone or gravel
The concrete for columns. shall be
mixed In the proportion OF one. Cd
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 az part
OF cement.
All mixing shall be done by machine
II 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 OF alkalis must be used
I'm all mixing.
Iron Stag or other similar porous
materials. may be used in place OF
broken stone or gravel, when APP
proved by the Department OF Build
tngs. and In such cases the Depart
ment OF Buildings may require n
reduction In the proportion OF the
Stag or other similar porous ma
terial I'm order TO have tho yoids
ton by volume. OF one % part Port
Sec. Ia. QUALITY OF MATER
ing bars used In reinforced con-
crete. shall be made by the open
hearth or the Bessemer process,
bars 10 be rolled directly from the
will be allowed. The steel shall
conform to the following limits In
chemical composition
Phosphorus shall not exceed 10
sulphur shall not exceed .os 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 (h) the uiti-
The lonsation per cent in eight
(s) inches shall not be less than
1.400, 900 ultimate strength. with
modification as follows: For each
increase OF one-eighth (h) inch In
inches, a deduction OF one Cd per
cent; for each decrease OF one-six-
teenth (1-16) inch in thickness, be-
low hve-sixteenths (5-16) inch. q
deduction OF two and one-naii
fest specimens for bending shall
be bent cold around a diameter
equal TO their least thickness. TO
tho following angles without frac-
ton:
For specimens one Cd inch thick.
so degrees.
For specimens three-quarter (k)
inch thick. 90 degrees.
For specimens one-half (h) incn
thick, Ito degrees. sa
For specimens one-quarter (h)
inch thick. t130 degrees.
For specimens three sixteenths
Ss-is5 inch I'll thick; i4 nl. degrees e.,
inch thick, 100 degrees.
OBJ CEMENT. The Portland
cement shall conform to the stan
dard specifications OF the American
Society for Testing Materials. In
minimum requirements for tensile
strength shall be as noted In Sec
tion rs OF this article.
Co SAND. The sand shall be
clean, free from any organic mat
td) sfoNE. GRAVEL OR STAG:
The stone shall be clean crushed
stone, free from dirt or dust ana
freshly broken.
The gravel shall be washed
The Stag shall be clean crushed
blast furnace Stag.
All aggregate must be or suoh
size as will pass through q tnree-
quarter t%) inch screen and pc re-
tanned on q one -auartsr th) inch
! Sec i6. MATERIALS PRoHIB-
TIED. The following materials
shall not be used In reinforced con-
crete construction: Boiler cinders.
and all similar Injurious materials.
Sec 16 CENTERING AND
FORMS. All monolithic reinforced
concrete shall be built on centsrs
All forms shall be built strong.
unyielding, plumb and true. thor
oughly braced and with tight
joints, so that no apprectable 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. Tor
cleaning and adjusting the steel
The opening shall not be closed
until the column IL to be poured.
Columns over fourteen l1D feet
In height, and under eighteen tdsp
mediate opening or pocket and the
pouring started therefrom. The
forms shall be thoroughly cleaned
Immediately before the concrete Is
foreign matters removed
Before removing the shores un-
der any beam or gfrder, the column
supporting II shall be stripped, SO
that the column may be examined
II 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 (1z)
hours after pouring.
The sides OF girder and beam
forms, may be removed at the ex-
piration or SIX COD days AFTER pour
The time which must elapse be-
fore removing the shores under the
girders and beams, will vary with
the weather. but in no case shall
they be removed In less than three
(3) weeks after pouring:
The supports under moor slaps
shall not be removed In less time
than ten (10) days after pouring.
but this clause is not intended TO
prevent removing the joists and
Tagging within a less time. provid-
ed the slabs are kept properly
Sec. IL 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 CD inches thick for
columns, one and one half uhl
inches thick on the bottom and
side OF girders and beams and
three quarters (k) inch on bottom
of floor slabs.
The amount OF concrete protec-
tion shall be clear OF the reinforo-
ing members.
Exposed metal centering or ex-
posed metal of any kind. shall not
Nn a thu