The Detroit times. [volume] (Detroit, Mich.) 1903-1920, 1910-10-05

\ ~
e Ssss had On poandO-sss As+
u Ac=nst cross section Of concrete
% As=nst cross section Of iongatudin-
"a al reinforcement.
g Where columns are subject to load:
20 Of known sccentricity. the combined
Is direct comprSssion aud the bending
20 moment shall not exceed the maxi
30 mum compression strsss allowed In
81 slabs and beams.
q The above .sr:ssss apply only TO 70
"a unsupported length to isast side or
IS diameter does not exceed nfteen
80 tl5). -
IS one Cd per cent. OF longitudinal re-
- enforcement, whether the same 10
10 used In the calculations or not.
II Proper provision shall be made for
" transmitting the stresses At the
IS spices In the coiumh, rods. and In
4 buildings over four 90 stories In
Is made between the loHsr and the up
u per ends OF the column rods.
IS In no case shall any column be
10 less than ten uo) inches In It's
20 smallest dimension.
Sec. 8. BENDING MOMENTS
AND CONTINUOUS ACTION. The
bending moment for slass and beams
with a uniformly distributed load.
when not continuous oyer supports
shall be taken at y WI.
When the slabs and beams are
continuous over both supports. the
bending moment for uniformly dis
70 tributed load shall be taken at not
4 less than one-tenth WI
9 Where slabs and beams are con-
8 tinuous over one 81 support only.
a the bending moment for uniformly
5 distributed load. shall be taken at
8 not less than one-ninth WI
Z In the case OF square panels, rein
8 forced In both directions and con-
. tinuous over all supports. the bend
u formly distributed load shall be TAX
5 WI.
a w==Load In pounds.
IS Length OF span in feet.
g Length OF span shall always be
Sec. I. STEEL OVER SUP
2 PORTS. In all cases where redue-
3 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
o that given for non-continuous mem
I bers
Sec. 8. BEAMS AND ORDERS
TO BE TREATED AS "T' BEAMS.
3 IL the Orders. beams and slabs are
poured in one "a continuous opera
3 nav be s treated as TT: beams. with
a portion of the slab as . nange. In
no case shall the ffange be of
greater width than the distance be-
% tween adjacent beams. or be as
4 sumed to extend to-'a distance On
/: each side OF the beam. greater than
3 three CD times the thickness of the
slab.
6 In all cases where the sheartng
9 stress along the plane OF junction
z OF the rib and fange sis excessive.
s the beam must be reinforced by
. means OF vertical or inclined steel
% members crossing well the plane OF
Sec. .. STEEL IN COMPRESS
SION in TRANsvERsE MEM
3 BEERS. Where IL Is necessary to in
troduce steel to resist compression
In Orders. beams or slabs, the COM
g pressive stress allowed on such steel
Z shall not exceed fifteen u5) times
3 the computed compressive stress in
3 the concrete at the same distance
Q from the neutral axis.
1 Such steel must be thoroughly
+. anchored into the mass OF the con-
wise to prevent any possibility OF
S buckling
Sec. 10. sHRINKAGE AND
2 THERMAL STRESSES. shrinkage
3 and thermal stresses shall be pro-
4 vided for by the Introduction Of
S steel.
Sec. IL. EXCESSIVE SHEAR.
2 When the shearing stresses devel-
4 concrete structure. exceed under the
s combined loads. the allowed shear
6 ing stress AZ fixed herein, a sum-
Z cient amount OF steel shall be intro
y duced In such position that the
(. deficiency in resistance to shear Is
Sec. IL. COLUMNS FILLED
2 WITH CONCRETE. Columns built
8 up Of structural steel shapes. Sc
S and rlled In solid and surrounded
8 with concrete. may be figured as
Z reinforced concrete columns, using
8 a stress Of eight hundred $500
3 pounds per square inch on the en-
l U2.000) pounds per square inch on
Q steel Where reinforced concrete
; beams frame into such columns the
4 entire end shear shall be taken by
s cts. properly reinforced. and con-
Z nected TO concrete core of columns.
s and moulded simultaneously with
3 columns.
2 GRADIENTS. The concrete for
walls, beams, Orders and floor con-
struction. shall be mixed In proper
ton by volume, OF one I'D part Port
land cement to two CD parts Of sand
and not more than four 90 parts of
either broken stone or gravel
The concrete for columns, shall be
10 mixed In the proportion OF one I'D
II part Portland cement. one and one
Y half dh., parts OF sand and three
IA In no case shall more than two t2)
10 parts Of sand be used to one I'd part
l6 of cement.
Ia All mixing shall be done by machine
Is II the total amount Of concrete ex-
10 ceeds fifty $50 cubic yards.
20 The proportions Of the ingredients
81 must be ascertained by actual meas
% urement. Clean water free from
% strong acids or alkalis must be used
2s Iron Stag or other similar porous
20 materials. may be used In place OF
2. broken stone or gravel, when ap-
% proved by the Department OF Build
% ings. and In such cases the Depart
80 ment OF Buildings may require q
81 reduction In the proportion Of the
80 Stag or other similar porous ma
81 terial in order to have the void'
Sec. H. QUALITY OF MATER.
IALs. ta) STEEL. All reinforce
ing bars used in reinforced con-
crete. shall be made by the oper
hearth or the Bessemer process
Z original billet. No rerolied stee
8 will be allowed The steel shall
conform TO the following limits ir
10 chemical composition:
IL PHOSPHORUS shall not exceed IN
l2 per cent.
Is Sulphur shall not exceed 9 per cent
IL Maganese shall not exceed so Pc
is cent.
Is Carbon shall not exceed so per cent
II All steel shall conform to the fol
ls lowing physical requirements:
10. The ultimate tensile, strength
2Os shall not be less than sixty thous
81 and (60,000) pounds per squar
% inch OF net cross section,