The Washington times., 1916-01-29
v - total shear.
b - Width Of stem Of Deam.

V - total shear.
- width Of stem Of Deam.
d. lever arm OF resisting couple.
OBJ For beams thoroughly reinforced with
web reinforcement the value OF the shearing
stress calculated as for tal l2O pounds per
square inch. The web reinforcement. exclu-
sive Of bent uD bars in this case, shall be
proportioned TO resist two-thlrds of The eN-
ternal vertical shear.
CcC For beams in which part Of the lonRi-
tudinal reinforcement Is used In the shape OF
bent up bars distributed over portion of the
beam IN a way covering the requirements for
this type OF web reinforcement, the maximum
vertical sheartng stress shall not exceed 80
pounds per square inch.
shearing stress uncombined with compression
normal to the shearing surface. and With All
tension normal to the shearinG plane provided
for by reinforcement. shearing stress Of 12O
pounds per square inch win be allowed.
Bond4 VIC bond stress between so eGnereSs nI,,,de
per square inch. and for drawn wire 40
pounds per square inch
Page l22. In Section 20, strike out:
'tSJ The ratio of the modulus OF Olasti.ity
OF steel 10 the modulus OF elasticity OF con
crete will be taken as fifteen d5)''. and in
"t3I The modulus OF elasticity Of concrete
shall be takeh as follows;
Ca) one-hfteenth OF that Of steel when the
strength OF the concrete IL taken as ZlOO
pounds per square inch or less.
(bD One-twelfth that Of steel, when the
strength OF the concrete is taken as greater
than 200 pounds per square inch but less
| than 29O0 pounds, and
OnH-tenth
strength OF the concrete Is taken as greater
| than 29OO pounds per square inch
| Page l2S. In Section SO. strike out that por-
| ton OF paragraph which begins with the
words, That f6r beams and girders.' etc.
and closes with the words, "at the middle OF
their lengths, and insert in lieu thereof tho
"FIir beams and girders the bending moment
| at center and at supports for interior GpeDs
will be taken as WI. and for end spans as
WI. for center and adjoining support for beth
dead and live loads. In the case OF beams
continuous for two spans only ihe % 6enSHtaE ISnlE
as WI, and near the middle OF the spaa as
WI.
| 10
Even n the center of the span is designed
! for a greater bending moment than is called
| for in ~ or "B'. the negative moment at
the support shall not be taken as less than
Page. Is3. In Section SO, in the third line
of next to the last paragraph ON said page,
| modulus OF fifteen u5)". and insert in lieu
| thereof the words. ION modHli as previously
siyen and on ON said Psse 10; ob SnS
! Immediately preceding the paragraph COM
mencing THE lateral spacing, etc, insert
The span length for beams and slabs shall
| be taken as the distance from center TO CEN
ter of supports, but need not pc taken TO en- ~
beam Brackets shall not be considered as
reducing the clear span IN the sense here in
| tended The length Of columns shall be
taken as the maximum unsupported length"
| Page 1873 In Section SO. strike out The last
paragraph, beginning with the words The
lateral spacing. etc. and ending on paGe
III with the words exceeding four 80 inches
in depth. and insert in lieu thereof the ioi-
The lateral spacing OF horizontal bars
| should not be less than three diameters cen
| ter to center nor should the distance from
| the side of the beam to the center Of tho
| nearest bar be less than two diameters. The
| clear spacing between two layers OF bars
should not be less than one inch. The use
| OF more than two layers is 20 he liscoura gee
unless the layers are tied together by ade'
quate metal connections, particularly at anC
near points where bars are bent zap or ben
down The use of mechanical saddles ol
spaCers will be required when directed ,y the
Inspector of Buildings.
graph beginning. "The diagonal tension
stress" etc. and ending and upon thu
'GsTib Strike ont the following, beginning at bot
'''i I'm a slab reinforced in two directions tn
clear span referred to in the following sen
| tence refers to the width Of the slab:
The thickness Of floor slab shall not h
less than one-thirticth of It's clear span bu
for roofs the ratio may be one-forty NTH.
Page rs. In Section 49, strike out tn
paragraph beginning. Where beams an
girders etc" and ending with the words
negative bending moment" and insert il
lieu thereof the following
| "In beam and slab construction en- euec
tive bond should be provided at the junction
Of beam and slab When the principal sIa
reinforcement is parallel to the beam, trans
verse reinforcement should be used. extend
. ing over the beam and welr into the siah
Where adequate bond and shearing resis
tance between slab and web of beam
= | provided, the slab may be considered as a
integral part OF the beam, but its effectiv
width shall be determined by the followin
rules
! (al II shall not exceed one-fourth of tn
span length OF the beam.
(bl Its OvPrhaneing width on either sid
Of the web shall not exceed four times tn
thickness OF the slab"
The above changes shall take effect q
. and after February l. 1916. OLIVER
~ NEWMAN. IOVTs RROWNTOW. CHARLIE
w, KUTZ, Commissioners D. g.