The Detroit times., 1911-02-20

Sec. @ PERMITS AND DRAW
INGS. Complete drawings. speci-
ncauons and details OF all rein
ing the size and position OF all re-
inforcing members. shall be filed
with the Department OF Buildings
before permit TO construct such
work. work shall be issued .nn For ali
submitted with the drawings and
specifications.
The live loads In pounds per
square foot for which the different
marked on each and every floor
plan OF the drawings submitted.
Sec. 3. METHOD OF cALcULA-
TON. In calculating the strength
or reinforced and plain concrete.
used for walls, columns. beams.
floor construction or for flreproof-
Ing, the thickness OF the concrete
only shall be used exclusive OF any
plastering or floor ballast.
Reinforced concrete slabs, beams
and sirders, shall be designed In
accordance with the following as
SYMPTOMS:
(a) The accepted theory OF nex-
ure shall be applied TO all MEM
bers resisting bending.
CD The steel shall take all the
tension stresses.
(c) The ratio OF the modulus of
elasticity OF concrete 10 that OF
tNtci Dt 10 10.
I'D The modulus OF elasticity
shall remain constant at all work
ing stresses.
(e) The stress strain curve OF
concrete In compression shall be
considered aE straight line.
Sec. T. ALLOWABLE UNIT
STRESSES. The following work
Ing stresses, based on figuring full
live and dead loads. shall be used;
(a) The allowable unit stress
for plain steel bars shall not be
more than forty-five (459o) per cent
Of the commercial elastic limit and
in no case greater than 10000
pounds per square inch.
(b) Deformed high carbon steel
bars rolled from billets shall not
be more than forty-five (45g) per
cent OF the commercial elastic limit
and In no case greater than $4,000
pounds per square inch.
(c) All other steel reinforcing
bars rolled from billets which pro-
vide compound, tensile and sheer
members, shall not be more than
forty-ilve $3.50 per cent OF the
case greater than 10000 pounds per
square inch.
(d) The allowable unit stress in
extreme fibre OF concrete In COM
preston. shall be six hundred and
hity (o5O) pounds per square inch.
te) The allowable unit stress
upon concrete In direct compress
sion. shall be four hundred and
nifty H6o) pounds per square inch.
Cd The allowable unit shear
Ing stress upon concrere shall be
forty GOl pounds per square inch
go The allowable adhesive
strength or concrete to steel shall
inch.
Sec. s. COLUMNS. (a) For Col
umns reinforced with longitudinal
bars tied at intervals not greater
ameter OF the bars. the safe load
shall be computed as follows;
Safe load lin pcunds)=6oo (Ac+
15As).
Ac=net cross section OF columns
In square inches.
As=cross section of longitudinal
reinforcement in square inches.
CD For columns reinforced with
longitudinal steel. and with spirally
wound hopping. provided. at least
one (1) per cent or hopping Ii used,
the safe load shall be computed as
follows:
Safe load lin pounds)=sbo (Ac+
15As).
Ac=net cross section OF concrete
enclosed In hopping.
As=net oross section OF longitudin-
al reinforcement.
ASAt tOAhinho tuDJcCt W iohdo
OF known eccentricity, the combined
stresses In the extreme fibre due to
direct compression and the bending
moment shall not exceed the maxi
mum compression stress allowed In
slabs and beams.
The above stresses apply only to
columns In which the ratio OF the
unsupported length to least side or
diameter does not exceed fifteen
Q6).
All columns shall have at least
one O per cent. OF longitudinal re-
Enforcement, whether the same II
used In the calculations or not.
Proper provision shall be made for
transmitting the stresses at the
spices in the column rods. and in
buildings over four 90 stories In
height, a proper connection must be
made between the lower and the up
per ends OF the column rods.
In no case shall any column be
less than ten !(10) inches In It's
smallest dimension.
Sec. 6. BENDING MOMENTS
AND CONTINUOUS ACTION. The
with a uniformly distributed load,
when not continuous over supports,
shall be taken at " WI.
When the slabs and beams are
continuous over both supports, the
bending moment for a uniformly dis
NAiDdNt0 iOhu dbhii DC tahch a. hoN
less than one-tenth WI
Where slabs and beams are con-
tinuous over one ~ support only.
the bending moment for a uniformly
distributed load. shall be taken at
not less than one-ninth WI.
In the case OF square panels. rein
forced In both directions and con-
tinuous over all supports, the bend
ing moment of the slab for a uni
formly distributed load shall be taxi
en- at not less than one-twentieth
WI.
W=Load In pounds
Length OF span in feet.
Length OF span shall always be
understood TO be the clear distance
between the supports.
Sec. Z. STEEL OVER SUP
PORTS. In all cases where reduc-
ton In the bending moment Is al
lowed on account OF the continuous
action, sufficient reinforcement must
be introduced In the top OF the slab
or beam over the supports, TO take
bending moment equal to the DIFF
ference between that allowed and
that given for non-continuous mem
bers.
Sec. s. BEAMS AND ORDERS
TO BE TREATED AS "T'' BEAMS.
II the Orders, beams and slabs are
poured in one ID continuous opera
may be treated as 1T" beams, with
a portion OF the slab as a fiange. In
no case shall the flange be OF a
greater width than the distance be-
tween adjacent beams. or be as
sumed to extend TO distance on
each side OF the beam, greater than
three (3) times the thickness OF the
slab.
In all cases where the shearing
stress along the plane OF junction
OF the rib and hange is excessive.
the beam must be reinforced by
means OF vertical or inclined steel
members crossing well the plane Of
Sec. 0. STEEL IN COMPRESS
SION IN TRANSVERSE MEM
BERS. Where II II necessary to In
troduce steel TO resist compression
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