ir
Most
ta dard
an
om itte
re
ri ti
te
19
rt ro
AC Manu oncr te Pr ct ce Th severa volume ar arranged to grou relate material
ri
rete
ti
ra ti
ts tura design an analysis structural specificati
in sets
tr
ia
ro
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merica ox 1915
ti
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ncrete Instit te edford Statio
Detroit, Mich 48219-0150
Th gram identify raft en te hnicians an in pect rs wh have de onstrate thei qualifications Th follow in progra ar ad inistere by CI to fulfil th grow in de an in th indu tr fo ertified wo er
thes
te hnical
om ittees
esponsible fo AC
om it
effo ts th user of AC do uments oc asionall ir je
incorrect.
Concrete
/atwor
inishe ec ni al Acti itie om itte iduals usin CI report an
on rete Constructi In pe to -Inrainin Concrete Construction Inspector-Leve/I This do umen AC ertifi atio
ay alread progra s,
into projec specifications
ontain eferen to thes hi an be in or orated
or qualit
reques from th AC Certificatio
olicit th help of indi tandards in identifyin
thei use. uf ACI d oc u
ar
ue te
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in information:
contro pro~p.rllJrA
Department
proble an specific sectio in th document 2. on is de iption of th pr bl io it problem. Th In titute's Engi eering Staf il review an ta appropriat ac io on al om ents an suggestion re ceiv d.
er
as well as on
ar en ou aged to as is in enhancin usefulness of AC documents.
rs
ofthe ln titute
th ac ur cy an
me St uc ur
P la i
AC an
C on c
Re
C o m m e n a ry -A C I3 18 .
Re or W.
R-89" R e
B y A C C om m i
31
Corley
Basile G. Rabb
Secretary
Chairman
James R. Cagley Gregor P. Chacos
Charles G. Salmon Ch st P. Si ss Robert J. Smith Me Irwi J. Sp ye De E. Stepha
Jame G. MacGrego Robert F. Mast Alan H. Mattoc
Francis J. Jacques Daniel P. Jenn James O. Jirsa Jame Lefter
James R. Harris
George Chironis Paul F. Fr tess Clifford
Richard E. Holguin
Luis E. Garcia ichard Gaynor Jaco S. Grossman David P. Gustafson M. so
Claude V. Baker
W al t Clarkson
Pinkham
Richar A. amse Lawrence D. Reaveley
li
Jr
Freyermuth
Vo Bi an O. Aalami
Gh
Philli
J. Iverso
Roge J. Becker
Roge Gree
Paul Kliege
Edward M. Fris ee
Philip G. Griffi
Car
Richar
W. Furlon
am
Cesa Caballer
August
Ma ti
Carlos De Vasconcelo
I-Iarol
P9tQ
ACI 318.1-89 (Revised 1992) do Concrete InstitUl July 1,1992 to supersed th
Institute'
stancardlzatlo
e r i ca l l in e
in th
saac D.
Luis Eduard
P. Isaacs
David
Kopczynsk
Michae E. Kreger
K. verson
Liaiso Juli
m et r
c om p
Pete Mart
Davi
Deni
James K. Wight
Mitchell
A. Whitin
Rudige Tewes
Henry Thonie
George Somervill
Mireya Velo
Ba Shengxi;
I-labi
Lgnkei
made in th pa 9uag
on
AC
ha
AC
u id e
ai
AI-Abidian
Projec Documents. II item found in thes document are r1m.in>ritn ec ey ho ra an n-
an
incorporated into th
t an da r
All righb
ar included inthis document
r ac ti ce s
a n C om me nt ar ie s
ar
a n m ea n t ro ni c o r
1992 America reserved
Projec Documents. Concret
e ch an ic a
d e i ce , p ri nt e
v is ua l r ep ro du ct io n o r f o u s unless perrrsssio
Referenc
to thes
document
shal no be
318.1/318.
R-
.",r..1
i n l ud in g t h m ak in g o f c op ie s b y a n p ho t
tion an
specifications
Institute.
.igl1l:; uf .eprwu"Uu
im;ludin
intended lo guidance in designing, planning executing. or inspecting construc in preparin
Strand
i nd ic at e h e 1992 changes.
no metric equivalent
e po rt s
Donald
Robert Park
da AC 318.1-89 in accordance with
318.1M/318.1RM;therefor o mm it te e
Jack P. Moehle
Shunsuke Otan
Laverd
Copyright om
Macinnes Lashgari
Member
procedure.
m ar gi n
Camero
in writin
in an
o r w ri tt e k no wl ed g
11"" in
p ro ce ss , o r b yan
o r o ra l o r r ec or di n o r r et ri ev a
is obtained from th copyrigh
fo
eleco un d o r
y s e m o r d ev ic e
oroorietors.
318.1/318.1 R·2
MA
AC Bu
whic this parg ap
Co
Pl
AL
CR
RA
CE
Co
Co ve is set. Vertical line in th ma gins indicate chan es from 318.1-89
is
ll
er
io
ed
te
R"
exclusi ve Lv
un
uu
er di
ce
de
CONTENTS
rs
l ai n c o in
genera building co AC 318 "Bui/ding Code Requiremenrs fo Reinforced concrete," Amon th subjects covere re permit an drawin s; in spection materials; concrete quality; formwork; contro joints ly is si ss st ct ITJ!:imur::rs (walls, (Doling, a n d p e de s ta ls )
1.1-Scope 1.2-Limitations 1. -P rmit an Drawings 1.4-lnspection
Keywords uildin co es compressiv joints; flexural strength footings inspection precas concrete
structural
le
ls
fo
3.2-Meta
Reinforcemen ials .4-Storage of Materi ls
4.0-Notation 4.1-General .3-Selection
ix 4.5-Evaluation
St of Concrete Proportion
Pl Co nd Accept nc
5.1-Formwork 5.2-JOints
Chapter
6.0-Notation 6.2-Pe missible 6.3-0esign
7.0-Notation 7.1-Walls 7.2-Footings 7.3-Pedestals 7.4-Precas
St esse
embArs
is writte in such
of Concrete
design
shee
walls.
strength
strength contro plai concrete
pecifications;
stresses
CO
ET
DE
MM
318.1/318.1 R·3
CHAPTER 1-GENERAL REQUIREMENTS COMMENTARY
CODe
1.1-Scope
RI.t-Scope
erecte unde requiremen of he legall dopted qenwh ll co define minimu acce tabl standard of design an construction practice
Th American Concrete nstitute "Buildin Code Requirement or Structural Plai Concrete (ACI 318.1) provides minimu requirements or an st uc ural plai concrete de an ct ed op intende
as
supplemen
go plai nc et ment in thos codes.
to th genera buildin
rodE';an th
wh
di ed es pr some uses of plai conc ete, such as plai concrete footings thos provisions have been delete from AC 31 an ar no containe exclusivel in AC 318. on
CI
presen practice no succcsaful
ed erie ce in th us
lain
conc et an unrein orce ma onry fo esidential an ligh commercial buildings. Thre ypes of plai concrete truc al embe ci al ed Ch (Section 7.1) footings (Section 7.2) an pedestal (Section
7.3). .2
code an "Buildin Code Re uireme ts fo Reinforced Co cret (ACI 18-89) (Revised 1992),," an shal ov rn in ll matt rs ertainin to st uctura plai concre esig an construction except wh reve this code is in conflict with requirements of th legall adopte genera uildin code Requir ment of AC 318.1-89 Revise 1992 should govern wher in conflict with requirements of AC1318-8 (Revised 1992).
Am rica
cr te In titute reco
that
th code be adopte in it entirety however, it is ecognize that when this code is made part of legall adopte genera od co provisions of this code
1.1.3-AI applicable provisions of ACI318 no in conflict with provisions of this code sh ll pply to lain concrete 1.1.4- hi code shal govern inal matter pert inin to design construction an material properties wherever
mended practice
referenced in this code
it wRlls,
applicable.
Rl.2-Limitation~
1.2-Limitations plai concrete members, define
as either unreinforced amount specifie
amount specifie sectio 2.
in AC 1318fo reinforced concrete
ee
orce concrete
lain
li
ported by othe structural member capabl 'Published by A m e ri ca n C o nc re t f e rr e t o a s A C I 31 B .
fo reinforced concrete is classified as plai co er cn ee Sectio 2. of AC 318.
of providin
I ns ti tu te , D e tr oi t M ic hi ga n . H e re af te r r e
concrete us ofplain concrete tructura member should be limite to member that ar primaril in stat of comp es
318.1/318.1R-4
AN AL
CR
P RA C
COMMENTARY
CODE rc
action provides
quat
latera
ompr ssio in
upport fo
unde al
tability an wher
ondition
al ulated
al conditions of loading. ig in'!
fo
rt
te byth
ua
or
legall adopte
id
la t,
le
li itly
rmit
genera building od
sian member that ca tolerate random cracks withou detrien to thei tr tura inte rity bers re tti tu ig te il tr th ility is buil te il tr sses to estr in fr sh inka temperatur ar considered an sufficiently reduce by constructio techniques to avoi uncontrolled cracks or when un co tr ll rack ue to uc restrain effect ca tici pate to occu in such manner that will no induce structural failur or collapse
It this code to provid serviceability requirements fo nonstruc tura member of plai concrete such as soil-supported slab (slabs on grade) Th
co
an
to sp ci ll
includ su
th at ri sufficie tl stif to ro id suppor to preven bucking.
1.2.4- lain on rete fo ompres io embers othe than ar he an as -in-plac iles an pier permitte inSection 1.2.2, shall be limite to pedestals. Se Sectio
7.3.
st c-
eq te latera
reinforc colu il li el ng it st ctura integrity, th code does no permit us of plai concrete for columns.
It
ll w,
we
ts us fo
tals
im
ited to rati ofunsupported height to leas latera dimensio le (S ti 7. .2). Plai concrete wall ar permitte (see Sectio 7.1) without absolute maximu height limitation However, fo multistor construction an othe majo structures AC Commit te
.3-P rmit
an
ra in in
ificatio
fo al
tructura
lain
orce cret Section R7.1_
il on rete co
truc
tion hall bear th ea of regi tere engineer or ar hi tect he drawings detail an pe ifications hall show: to
hich de ig lo
ig
any reinforcemen
etails nd lo atio
of al ontrol joints
with th drawings when required by th Building Official
calculations
permitte
to supplement calculations
1.3.3-Building
fficia
eans th offi er orother de ig in
representative.
.3
rmit
.3.1-T pe ific ti s,
co ra es
io
th us of wall
bers in
nd
or an
si ne
rein-
with AC 318. See
rawi gs
ovisio fo re rati is ua of ermi
intended as supplement
onform
stages of construction
(e
IS strongly
of esig re in
ra ings eral
thereto.
Th list th re impo ta it in rmati th us in lu ed in th si ra in s, tail specifications Th code does no impl an all-inclusiv list Official.
DC
COMMENTARY
CODE
1.4-lnspection .4.1 As
R1.4-Inspection
inimum concrete constructi
sh ll
in spection responsibility.
concrete construction shal
that engineer or architec
drawings and specifications. genera building code inspection record shal include: (a Qualit an proportion of concrete material an strength of concrete (b Construction an remova of form an reshorin c) Mixing pl cing an curing conc et (d Placin of an reinforcemen pleted members, or wall members
(g Gene al prog es of work kept of cret during placemen an curing 1.4. -Rec rd ngin er
of inspection requir
architec
or
in Sections 1. .2
ye rs or long
afte
om le
io
CHAPTER2-DEFINITIONS R2.1- Th definition
this co e. orothe term used inthis code re erence is defi ed
Sp cializ
definition
mu 25 percen reductio fo th pu pose of re ucin
imember thickness) used uildup intern stress
Plain
in co tain less einf rcemen th th mini um speclfled in AC 318 fu reinforced concrete than it fina position in th structure.
plain
structura purposes.
es
code fo reinforced concrete.
ri
Structural
et
appear in individua.l
chapters.
Control jOint-Construction
give ar fo us applicatio of this code only an do no always co re pond to ordinary sage
moun
he definition
co tr
in in this code is
nt to
rv
th purpos of plai conc et construction only Se ection R5.2 fo detailed discussion ofjointing an th importance of jointing in plai concrete construction Soil supp rted labs uc as slab on rade ar no consid ered to be structural slab within th contex of th definition fo "structu al plai concrete unle they tran mi vertical load ro othe pa ts of st ucture to th oil.
318.1!318.1R-6
MANUAL OF CONC ET
PRAC IC
HAPTER 3-MATERIALS CODE 3. -M
ials
fo
COMMENTARY
rete Se commentary sections of AC 31 fo detailed discussion of applicable material requirements
of AC1318
3.2-Me al
rein orce en
AC1318. materials 3. .1 Buil in Offici hall have th ight to rder es in of an material used in plai concrete construction to determin
if
at ials ar
of uality sp
ified.
.3.2 Test of mate ials an of oncr te sh ll be made in ac ordanc with ta dard of he Americ Societ 318. concrete shal be
de
vail bl
fo inspec io
proj ct an hall reserv or architect for tha purpose.
urin
in pe ting engineer
3. .1 Cement an aggregi:ltes sh ll be stored in su manner to preven dete io atio or co ta inatio from foreig matter contaminated shal no be used fo concrete
HAPT
4-
NCRETE
QUALITY
4.0-Notation f:= specifie
compressiv
strength of concrete ps
4.1-General
minimu
averag compressiv
5.3.2 iz
frequenc
Qual ty cont ol requirements fo
strength as prescribed in Sectio
of strength
Section 5.6.2.3 of AC1318
belo
f~
4.6. of AC1318 .1.3 Unless ther is specified, ~hall be base on 8-da tests. othe th 28 da s, test ag fo shal be as indicate in design drawings or specifications pressive strength of concrete cret member is designed
fo whic
ac
lain co
lain conc et ar th
concrete strength fo plai
am
concrete construction
plicable commentary sections of AC 31 fo detailed discus sion of concrete qualit requirements
PL
CR
CO
ND
OM
31B.11318.1R-7
CODE
-Minim
COMMENTARY
tr ng
Specified compressiv
R4.2 Minimu
strength
t;
strength
inimum strength re uire en
ai
fOT
co cret
co
ct on es ec as solely on trengt an qualit of concrete treate asa homogen at al an co ce adequately homogeneou material or well formed surfaces
psI.
.3 Sele tion Selectio of conc et tion 5. of AC1318
of co cr te proportion prop rtions shal confor
to Sec-
Mixing an placin of concrete shal conf rm to Chapte of AC1318
concrete Evaluatiun an acceptance of co cret Section 5.6 of AC1318
shal conf rm to
5.1-Formwork shal confor
to Chapte
of AC1318
S.2-Joints
RS.2--Joints
shal be provided to divide
Joints in plai conc et construction ar an impo tant de ig consideration. In einforce conc ete, reinforcemen is pro-
limite
struct ra member into fl x-
to cont ol buildu
of excessiv
Internal
sh inkage an temperatur effects. In plai concrete joints ar he only design mean of controllin an thereb reliev
effAr.t~_
us
smalle elemen al es
in li atic
ondition
selectio
an
ro ortionin
of
at
rials; ixin placing, nd curing of concrete degree restrain to movement stresses du to load to whic elemen is subject; an construction techniques he drawings or in th specific ti ns Se Sectio An
id
1.3.1.
plain .concrete
joint.
contro th buildu of th interuc oint co al on or flexural tensio ca be develope ac os joint, conditio referred to by th code as flexural discontinuity. made Each construction must be studie en oc ck
individually to de co
eratur ot ct al erwi cceptable such as tran vers cracks in continuous wall ootin
transv rs
nd
control.joints
re ot necessary. Control joints
ma be provided at intermediate location betwee outsid edge an construction joints subdivid larg plai conen er ay ve
made only at joints S.2.6-Walls
dowelled to othe inte sectin latera stability.
ug
by joints
me bers as required fo
ct meta or shee plasti 01,
for UICU, sawed
VI
insert watersto type rubber in erts tooled groove in th concrete surfac to
au thicknes of th concrete sectio at thes insert or atformed, 25 pE'Ted es be reduced at Ie:Jl.~t
3l8.1{3l8.1R-8
AN AL
NC ET
RA
COMMENTARY en to in sectio
th
tr
fo so
join effect ve with
egre
of aggregat
em in
interl ck to
ld th
sidere an acceptable practice to augmen th aggregat interlock with specia attentio to alignmen of such dowels an to rote ti from rrosio (w ic satisfie th inte tio 5.2.4)
CHAP
6-ANALYSIS
AN
DESI
6.0-Notation Fo plai concrete th basi design concep that th member
urfa
that is ge
io etri ally imilar to an
on
reinforcem
re ir
that crac condi(·i on stre is et sufficie tl lo to ro id an unde factored loadin conditions
ctio
in
tained fo al loadin
specifie compressiv strength of concrete psi, Se Chapte square root of specifie compressiv strength of concrete psi. averag splittin tensil strength of lightweigh
ra ke
se ti
5.1.5 overal hi ne of ember, in effectiv length factor Se Sectio erti al dist nc etwe upport
7.1.5. in
VII
section II
lo id load or re ctio area tr
th
6.1-Desig
du tion fa to
tion
.2.2
etho
6. Desi
adeq at trengt in ac ordanc with provisions of this code usin load factor an permissibl stresses bination as pe ifie
in ection 9. of C1318. shall
no exceed permissibl 6.1.4-Wher
stresses give
er is ible
tresse
in Sectio 6.2.
et
te stre se it in permissi le stre li it Wh pute stresses du to load exceed th permissibl stresses to th concrete strength specified, th sectio must be increase embe desi ne
as
reinforced concrete
danc with AC 318. Th designer should note however, that an increase in concrete sectio ma have detrimenta effect
re to be exceeded shrinkage, an temperatur
signed as reinforced concrete member in accordance with appropriat design requirements of AC 318for rein force
concrete
embe in accor-
effect ma increase
eA DC
CODE
COMMENTARY
6.2- ermissible stresses
.2-Permissible stresse
following: (a Flexur Extrem fibe stress in compressio
f~
54>Vf
Extrem fibe stress in tension"
2. Th ermissible stre se in fl ural te si sh r, eari ar th sa er itte fo pl in co rete ed 31 code. Th permissibl stress values fo flexural an axia compression ar new. Applicatio of th frustrum to find for permissible bearin tr th in lope te pe su rt is illustrate in mentar Sectio 10.1 of AC 318.
(b) Axial compression 0.60
(c Shear" Beam action
2q- -v ,;
[2+ J$
Two-wa action
Y'f nl ' Pe nn is si bl e lightweigh
s he a a n
aggregat
t en si o
concrete
(a)When is specifie 5.2 of AC1318. f,16.7
s tr es se s a pp l f o n or ma l w ei gh t c on cr et e f o on
of th
followin
modification
shal apply:
an concrete is proportioned in accordance with Sectio ll be ub rV ut o f f.,l6.7 shall
notexceed~ (b) When
et
is no
ec
d,
ll
be
ie
by
l ig ht we iq ht " c on cr et e a n b y 0 .8 5 f o " sa nd -l ig ht we ig h c on cr et e p ol at io n i s p er mi He d w he n p ar ti a a n r ep la ce me n i s u se d up or ng
rt
de
de
ha
he
"a L in ea r i n e r
de
ar
m is si bl e b ea ri n s tr es s o n h e l oa de d a re a m a b e i nc re a e d b y n o m or e t ha n 2 . W he n t h s up po r i n s ut 1a c i s s lo pe d o r s te pp ed . A. e a of l oa de d a re a a n
ba
h av in g s id e l op e
he
ge
o f 1 v e r i ca l t o
pe but
ofa ri
or
h or iz on ta l
6.2.2- trengt redu tion fa to j> fo flexure, compresion, hear nd bearin of plai on rete hall be 0.65
R6.2 Th stre th re ti fa to j> fo plai si is th sa ll st es itions flexural tensio strength an shea strength fo plai depend on th tensil strength characteristic of th senc of reinforcement, equa understrengt bending an shea ar considere
G.3-Design flexur an axia load hall be ba ed on linear tres strain relationship in both tensio an co pression
stresses will no exceed permissibl lion
.2
factor fo both
appropriate
R6.3-Design R6.3.1-
6.3.2en il trengt of on rete in de ig lain on rete ember'
concrete ince th concrete concrete
ay be on idered he ro isio of stresses Se Sec-
Th cod assumes that plain concrete is
homoge-
ou teri able ai tainin se tially li istributio of strain nd tr sses th full ra load in conditions even to ultimate Fo design convenience, th de assu triang la tr ss is ri ti le re it in th rmis ible fi tr sses tr sses te th tr ig t-li th ry re tual tr ss s; es lt th permissibl stresses ar reduce tu accoun fu th difference in actual behavior versus assume behavior lain co rete rs to st in load ro id th te st es ce th er is ible ro id contro joints ar properly designed spaced an constructe to
ie
th
catr in
ulti
creep, temperature, an shrinkag effects.
il
tr
ue
318.1/31
NU
R-
ON
ET
AC
CODE
COMMENTARY
6.3.3-No strength shal be assigned to ment that ma be present.
etal reinforce-
R6 er ntai than th minimu amount pecified fo reinforced concrete must be de igne asplai concrete wi trengt ba ed on th intended appl reinforcin used fo th pu pose of transferrin an external forc to plai concrete dement
6.3.4- Tensio shal no be transmitte hrough outsid co join vidual plai concrete element. No flexural continuity du concrete elements.
outsid edge or join (constructio or contro joint) is consid ered as eparat tructura element. Compressiv an shea forces ma be transferre to adjacent elements Flexural coninuity causin developmen of tensil tres betwee adja cent elements
except fo concrete cast agains soil verall thickn ss shall in less that actual thickness.
load shal be ll pression give in Sections
.2.1(a
st nd (0 shal be less
R6 he es fo conc et cast agains eart is to allo or unevenness of excavation an or om contaminatio of th concrete adjacent to th SOIL
R6 ai ur an axia compressiv th compressio face
il hi
lexu s t e s in tensio
6. .7-Shear
ia give
in Sectio
ust be prevented.
be load ar proportioned such that on
Calculated
Calculated axial stress
ce 6_2_1(a)_
strength
an that on th tensio
ace:
wher th pe missible
tres es ar as give in ection
RIl.3.7-Shear
trength
Proportion of plai conc et member will be controlled by tensil strength athe than shea st engt fo th usua plai concrete
embers
ractical
roportions
ea stress (alia
en es wi ol However, sinc it is difficul to forese al possible conditions er ea Committee 31 decide to ma ntai th investigatio of hi as es di co qu en experience designer will soon recogniz wher hear no cntica to plai concrete member an WIll adjust hi design procedure accordingly.
ll
v, fo rectangula
sections
( 6- 1
where
6.3.5.
R6.3. 7.1-
cipa tensil
he hear requirements or plai conc et as ed ar al ng tres near th cent oida axis become equa to en cret
of th principa tensil tres come from th hear th code safeguards agains tensil failur by limiting th permissibl for ro VQI/b, where and sectio of homogeneou material tion considered.
is th statical
omen of th area outsid
DC
CODE
COMMENTARY gros section, is th and is th idth wh re This lain
ti re gniz cret nd th
shea stress tangular.
will
V=
ea
in rtia tr ss is
he mo ce tr ti
be abou SO
th in og
rc
reat
ro
ctio te
us ture ar tr ss th th
th
(';UIlI-
VQllb
ca
ci
homogeneou
material ma be appropriate.
Vu
uled at
distance
om
ic
on
same shear. hall no ex ee
permis i-
6.2.1(c).
7.0-Notation Ago
r,
nw
io in perimete of critical sectio fo shea in footings in. specifie co pressive strength of concrete psi. Se Chapte overal thicknes of member in effectiv length factor er ical di tanc betwee upport in Sectio
7.1.
Vu
section factored shea forc at sectio
7.1-Walls
R7.1-Walls in footings foundation walls,
ported by sailor supporte
1.2.2. ls
construction fo residentia an ligh commercial building in lo or ei ic re s. lt ug th im es cret walls, designer ar cautione agains extrapolatin th erie it relati el inor st ucture si la
ll
co cr
wa
ul
posses some ductilit
it
ll in
than 0. Oh. therwi e, plai on rete alls hall be de signed unde provisions of Sectio 7.1.5. 6.3.7.
uc
structures wher differential settlement
subjected.
Sectio
co
an abilit
wind earthquake
to maintain thei integrit
tr ly en ra es th se ll si reinforced concrete member in accordance with AC 31 fo reinforced \;Om:11;[1;;.
he ro isio fo lain cret wall re li able ly or wall laterall pp te in uc nn to ro ibit relative latera displacement at to an bottom of individual wall elements (see Sectio 7.1. 6.4) This code does no cove wall wher ther is no horizontal suppor to prohibit relative is lace en at to an bottom of wall elements
uch late
318.1/318.1R-12
NU
NC
PR
CE
COMMENTARY
CODE
ally unsupporte wall mu be designed as reinforced concret member in acco danc with AC 318. Plai concrete wall as structural member ar ubject to th limitation of Sectio 1.2_ an th jointing requirements of ecti
5.2, whic
reatly affect thei
esign.
lain concrete
subjected, includin eccentri axia load an latera forces In general, th provisions appl to wall spanning vertically Al em ca ec ap only to wall of soli rectangula cros sections othe shapes must be de igne accordin to Sectio 6.3.6. Plai conc et
wall mu
be de igne
fo combined flexur
wall to be compressio member with flexure, unle in th equi ements of Sectio strength ma also need to be investigated
7.1.S-Empirical
design
cros sectio ma be desi ne overal thicknes
by Eq 7-1) if resultan of middle-third of the in
where
Se
0.65 an effectiv
(7-1)
le gt factor
shal be
tion an
7.1.6-Limitations
7.1.6.1-Unless
demonstrated
detailed analysis,
each vertical concentrated load shal no exceed center to-cente distance betwee loads, no widt bearin plus time th wall thickness. ls less height or length whicheve is
than 1/24 th unsupporte
!in
foundation wall shal no
ck ay be
esigne
usin
th
si
'S
k€cJ'J
q,/;
designmetho
lified Eq (7
). Eccentri
load an latera fo ce ar used to dete mine th tota eccenen xceed h16, considerin as concentric load Th factored axia load q , ~ w , com-
of wall
wa shal be computed by
0.45
7.I.S-E pirica
etho
meet ea
less than 7% in
.1.6.4 Wall shal br ce agains late al tran la tion Se Sectio 5.2. an 6.3.4.
ll in Su extend at leas 24 in beyond th corner of op nings.
~w
reflect th geueral rauge uf braced au restrained cu
condi-
tion encounte ed in wall de ign. he limitation of Sectio 7.1. appl whethe th wall is proportioned by Sectio 6.3. or by th empi ical etho of Sectio 7.1.5.
DC
COMMENTARY
CODE
7.2-Footings 7. .1-Plain
R7.2-Footings
conc et
provided in Sectio nfactore
orce
footings shal be desi ne
orfac-
7.2. an
moment
transmitte
ooting
principles of soil mechanics. piles. less than
in Se Sectio
R7.2.4et trolle by flexural strength (extreme fibe stress in tensio no
6.3.5.
re te
')
th
tr
th
th
ua
proportion of plai concrete footings Shea rarely will control se Sectio R6.3 7. Fo ooting ca agains oil, over all thickness used or st engt computat on us be take ac excavation an contaminatio of th concrete adjacent to soil thicknes uf
in., calculations fo flexural an
al
ck
7.2.S-Moment in plai concrete footings Maximu factored moment shal be computed at critical sections locate as follows: supporting concrete column pedestal or wall. (b) Halfwa betwee rntddle an edge of wall forfootin supporting masonr wall base plate, or fo ting su po ting base plate. h ea r
co cr
column with stee 7.2.6- be
oo
7. .6.1 Ma imum fa tore hear shal co pu ed in ac ordanc with Sectio 7. .6.2 with location criti-
wall th
wall. critical
fine
ctio
in Sectio
hall
asur
from location de
7.2.5(c)
Sh governed by th
at distance
lo or severe oftwo co ditions: in ro
face ofconcentrate
lo
or eac-
sign in acco da ce wi Se tion 6.3.7. (b wo-w action fo footing, with critical sectio its perimeter
is
mini um bu
ee no approach
closer than hl2
designed in acco danc 7.2.6.4.
with Sections 7.2.6.3. and
in pl in co cret
otin
shea stresses
318.1/318.1R-14
AL
ON
ET
AC
COMMENTARY
CODE
R7.2.6.3-As or beam action shear, hear tres or twoay action fo plai concrete footings is calculated us ng th
Vu
Jl where
and
in
(7-2)
shal be take atth critic
io
ls overal
footing. Se Sectio
sectio
e-
equation fo
section of ho
geneou
ateria
VQllb)
(v
sinc th critical principa tensil stress near mid-dept footing will approximate this value,
ofth
thicknes
6.3.5. st
v; shal no
xc ed permissi
6.2.1(c). -C
ly
l-
ls moment an shear. su
su is
give in Sectio
6.2.1(d)
7.3-Pedestals
R7.3-Pedestals
subjected.
Th height-thickness limitation fo plai concrete pedestal does no appl fo portions of pede tals embedded in soil ca pabl of providin latera restraint.
7.3.2-Rati of unsupporte height to verage le st later dimensio of plai concrete pedest ls shal no ex 7.3.3-Maximu comp essive stress in plai concrete edestals shal no exceed pe missible bearin stress give in ection 6.2. (d).
.4-Precas ig
R7.4- recast
embers la
reca
tructura
embers embers
re ubject to ll
provisions fo cast-in-plac
7.4.2-Limitati ns cite in Sectio .2 appl fo recast member of structural plai concrete no only to th fina conditio bu also during fabrication. transportation an erection.
tion of th internal tres es du to hrinkage take plac prio er ct ca on on ha an ed er
y, pabl of resistin
such forces
me an st uctura in egrity unti tion ar completed.
su erma en
ig co nec-
different tha
fo
concrete containe
limitations an in this code
co side al lo ding conditions from initia fabricatio to completion of th structure, includin form removal, stor age, transportation, an erection
cast in plac
concrete sinc
th
ajor
or
in
id
it io st co
if io
s,
ch
s,
All
iv ie
la
im
iv ie ct
ci
cl ly is
si
lo ir
in
se ch s;
lo
st
li le ir ci
su
iv co
ci st
cip
ic
io
te in titute OX
91
D FO R
AT ON
