The Washington times., 1916-01-29
V = total shear.
b = Midth OF stem Of nean.


id - lever arm OF resisting couple.
CbI For beams thoroughly reinforced Win
web reinforcement the value OF 'he shear,ng
stress calculated as for 'al 10 POUNDS per
square inch. The web reinforcement. eNclu-
siNc "f bent uU bars in this case. s1aIl he
proportioncd to resist Iwo-thrds of he en-
ternaI vertical shear
,c, For beams in which par OF the onei-
tudnal reinforcement is used In the shape OF
bent w bars distributed over portion of the
beam IN a way covering the requirements Tor
this type Of web reinforcement, the maNirnum
vertical sheartng stress shall not exceed 6O
pounds per square inch.
I'D Where punching shear occurs. that s,
shcaring stress uncomoined with compression
normal TO the shearing surface, ana MIN all
tension norma! to the shearing plane provided
for by rcinforcemrnt shearing stress "f l."
RondS Yhc bond stress between concrete
and plain hsra shall he taken as 50 pounds
per square inch and for draw" wire 'o'
Taec H. In Srction 20 strike out:
'',3, The ratio of the modulus Of elasti sity
crete viii be takcm as iiIten l5)" md in
scrt In lieu thereof ihc following:
"C' Tho modulus Of elasticity Of concrete
shall he lalinn as follows:
"a, unc-fftrenth Of that OF st.el when the
strength OF the concrete is taken as 2ec'
rbr Onc-tweIlth that OF steel, when the
strength OF the concrete is taken as greater
than ZOO pounds per square inch but less
co. Onc-temth that Of steol. when the
strength OF tho concrete is taken As gr eater
page rs In Section So. strik" out ,hai pcr-
non OF paragraph which begins with the
Words, That for beams and Sirders &C;
and closes with the words, at tho middle OF
their lengths and insert in lieu thereof tho
.'F,I hrams and girlors the hcnIins moment
at center and Al supports for interior spsns
ill bc taken WI. and for end spans as
L
WI for center and adjoining supper; for both
dead and live loads. In the case OF beams
continuous for TWO spans only. the bendihE
| moment al tn" central supnort viii he taken
as WI: and near the middle OF the Sps7 as
w.. y
| Even II the rcntcr Of tho span is designed
for A Erca ter bending moment than Is call ID
! for in ~ or "B'. the negative moment at
the support shall not hc taken AS less than
rage IL. In Section 49, in the third line
of next to the last paragraph on said page,
| strike out the words upon ratio OF
| modulus OF fifteen u5)". and insert in leu
| thereof the words, ''on modui as previously
| given, and on said page E3 inllnediAtciy
oowne the next 10 !He ~, last paTnsrHPn co1 anI
mencing, The lateral spacing etc. Insert
the following:
| be taken as tho distance from center TO cen
| ter of supports. but need not D" taken I" "\-
! coed tho clear span plus the depth 81 Ian or
| beam. brackets shall not be considcrer as
| reducing the clear span in the sense here in
tended. The length OF columns shall H."
| taken as the ma Nimum unsupported lenSth.'
| Page I.3 In Section SO. strike out he last
paragraph. beginning with the words. " Thc
lateral snac'ms e'G aMd Sn%ns Eor on rSSs
| in depth. and insert in lieu thereof the iol-
| lowing:
should not be less than three Gtameters cen
| ter to center nor should the distance from
the side of the beam to the center OF the
nearest bar he 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 TO he liscoura sed
! unless the layers are tied together by adc-
| quate metal connections, particularly at and
| near points where bars are bent ap or bent
| down The use of mechanical saddles or
spacers win be required when directed ~ the
| Inspector of buildings.
graph beginning. The diagonal tension
stress" ct, and ending and upon the
supports"
Strike ont thH following, beginning al bot
I'm slab reinforced in two directions tho
clear span referred to in the following sen
! ,oncc IcIcrs to the width Of the slab:
The thickness of floor slab shall not nc
less than onc-thirti"th Of It's clear span. but
! Page 10. In Section s., strike out tho
paragraph ~hrginunG, 'Nhcre heans and
gtrd"rs: etc." and cndinE With the words
| 'uCGatiNc bonding moment" and insert IN
lieu thereof the following:
In beam and slab construction Pn crCc'
tive bond should be provided at the junction
Of beam and slab When the PRINCIPAL ,lnr
reinforcement is parallel to the heam, trans
verse reinforcement should he used. extend
ing over the beam and weIr into the sab
Where adequate bond and shearinG resis
tance between slab AMI web ~ beam Is
provided the slab may he considered ar
integral part of the beam but its effective
width shall be determined by the following
rules:
,a) II shall not exceed onc-fourth of tn,
span length OF the beam.
CbN Its overhanains width on either sid,
of the web shall not exceed four times the
| thickness Of the slab"
! The above changes shall tax" effect ov
and after February !. 1915. OLIVER n
y NEWMAN. Louis RROWNT OW. CHARLES
| W EI'TH, Commissioners, y. 9.
|