Evening bulletin., 1911-06-09

working stresses shall not be exceed
ed:
Lbs. per 50 in.
Iron in tension .............l 10000
Medium steel in tension .. 10000
High steel in tension 10000
Steel in compression .......tO.OOO
Steel In shear 10000
Concrete In direct compress.
sion ......... ............ 300
Concrete extreme fibre In com
preston ......... ......... 700
Concrete In shear .......... so
REINFORCED CONCRETE AsSuMP-
TlONs.
Section 46 All reinforced concrete
work shall he designed in accord
ance with best standard engineering
practice. The following assumptions
may be made:
when beams and girders are made
monolithlc with the floor slab, they
may be computed az 'T" beams The
width OF slab which may be consider
ed part of the beam will depend upon
the shearing stresses. but in no case
shall such total width exceed three
times the width of the beam.
REINFORCED CONCRETE coli
uMNS.
Section a. The column rods shall
be tied together by steel hoops spac-
ed not more than twelve u2) inches
apart.
When the unsupported length OF
| concrete column exceeds twelve Q2)
| times Its least side or diameter. tho
allowable compression of the concrete
shall he taken ~ five hundred (5O0)
pounds multiplied by the least side
or diameter Of the column In inches
and divided by the unsupported length
In feet.
For exterior columns subject to &C.
centric loading or bending OF an in
determlnate amount, the above stress
shall be reduced at least twenty (2O)
per cent. When the bending stresses
in column can be definitely determ-
ined the combined bending and direct
stresses shall not exceed FIVE hun
dred t5OO) pounds per square inch.
In buildings over four A) stories
high sufficient steel reinforcement
shall be used tn carry at least seven
ty-fiye t75) per cent OF the dead load
of the floors and roof. figuring ten
thousand 100000 pounds per square
inch on the steel. except when In
buildings Of any number of stories the
columns arc large enough so that the
concrete alone will carry the total
live and dead loads with stress OF
not over flve hundred (500) pounds
per square inch the amount of steel
reinforcement may be reduced to not
less than one "a per cent of the
cross section area of the column.
Proper provision shall he made for
transmitting the stresses at the
splces in the column rods.
In buildings over four (4 stories
high all splices in the reinforcing
steel below the upper three floors
shall he made by means OF riveted
connections, sleeve nuts, turnbuckles.
or some approved positive connection.
COLUMNS FILLED WITH CON-
CRETE
Section As. Columns composed OF
/ structural steel shape, lattlced togeth-
er by riyeting and filled in solidly
and surrounded by coucrete, may be
computed as reinforced concrete col
umns except that the allowable stress
In the steel may be increased TO twelve
thousand u2,OOO) pounds per square
| inch.
CONCRETE COLUMN PROTECTION
| Section 40. The outer shell OF a
concrete filled steel column shall he
considered only as hreproof cover
ing.
PROTECTION OF STEEL.
Section so For the purpose OF hre
protection the reinforcing steel shall
be kept away from the surface OF the
concrete one and one-half (1h) inches
in columns, one inch In beams and
| girders, and y inch In slabs.
STEEL IN CONCRETE.
Section 81. All reinforcing steel
shall be subject to test by an approy-