ST9802-SP 981016WRIGHT
CONSTRUCTION
C O M PA N Y
DATE: OCTOBER 16, 1998
PROJECT TITLE: DRAINAGE AND PAVING IMPROVEMENTS
SOUTHWESTERN DRIVE, FREEPORT PARKWAY,
AND FROM FRITZ ROAD TO GRAPEVINE CREEK
CONTRACT IDENTIFICATION:
CONTRACTOR:
SUPPLIER:
MANUFACTURER:
PRODUCT:
SITE UTILITIES
WRIGHT CONSTRUCTION CO. INC.
HYDRO CONDUIT
HYDRO CONDUIT
BOX CULVERT C - 789
I, t_ (SIGNATURE)
A DULY AUTHORIZED REPRESENTATIVE OF
Lj eZ 4 147 C O 1A ST. C o __T-MC ((;'ONTRACTOR)
DO HEREBY CERTIFY THAT CONTRA TOC R HAS FIELD VERIFtE7
DIMENSIONAL ACCURACIES RELATED TO THIS SUBMITTA
AND FURTHER CERTIFY THAT CONTRACTOR HAS MADr A,
PROPER EFFORT TO ASSURE THAT THERE ARE NO EXCEP-
TIONS TO THE CONTRACT REQUIREMENTS (UNLESS Si ECIFI
CALLY IDENTIFIED IN ATTACHED LETTER DATED ;
SUBMITTAL DATE 1 Q - 1 ( - cL19
CITY OF COPPELL
,1,i I;� Trl I �jf: C i T Y ' ;F r"01 EI L
Liltia;:`v�,L.
e
DATE
Wright Construction Co., Inc.
601 W. Wall 4 Grapevine, TX 76051 • Metro (817) 481.2594
♦��
Hydro Conduit
Reinforced Concrete Boxes
t
•. t
L
t SPAN • '
SPAN (ft.)
3 4 5 6 7 8 9 10
2
3
4
5
w 6
ac 7
8
9
10
4 5 6 7 8 8 9 10
WALL & HAUNCH'Y (in.)
Note: Numbers in boxes are approximate weights per foot
A • : a
TYPICAL J01 NT
NOTES:
1. Produced to current A.S.T.M. Specification.
2. This drawing is not intended to show
reinforcement design– either as to placement or
steel area. Actual project specification or current
A.S.T.M. specification will govern.
3. Consult Hydro Conduit Corp. local representative
for further details not listed on this drawing.
DALLAS /FT. WORTH
3 /4 Miles NE from Intersection
ofSH114 &135W
P.O. Box 1230
Roanoke, Texas 76262
(817) 491 -4321
CR 146
11, 30, 31, 32, 33, 34, 35, 37
Issued 1'89
ommom
.
0000..-.
■O
:III
M
.II
till
..
■.®
Kr
till
Ill
®®
■-.m
•Ill
r l l
m
:r..
■-..
r l l
M M®
.-...
', 11
mM
■--...m®
wmmm mm.m
4 5 6 7 8 8 9 10
WALL & HAUNCH'Y (in.)
Note: Numbers in boxes are approximate weights per foot
A • : a
TYPICAL J01 NT
NOTES:
1. Produced to current A.S.T.M. Specification.
2. This drawing is not intended to show
reinforcement design– either as to placement or
steel area. Actual project specification or current
A.S.T.M. specification will govern.
3. Consult Hydro Conduit Corp. local representative
for further details not listed on this drawing.
DALLAS /FT. WORTH
3 /4 Miles NE from Intersection
ofSH114 &135W
P.O. Box 1230
Roanoke, Texas 76262
(817) 491 -4321
CR 146
11, 30, 31, 32, 33, 34, 35, 37
Issued 1'89
ISM Designation: C 789 - 94
Standard Specification for
Precast Reinforced Concrete Box Sections for Culverts, Storm
Drains, and Sewers'
This standard is issued under the fixed designation C 789; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (t) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification covers single -cell precast reinforced
concrete box sections intended to be used for the construc-
tion of culverts and for the conveyance of storm water,
industrial wastes, and sewage.
1.2 A complete metric companion to Specification C 789
has been developed —C 789M; therefore, no metric equiva-
lents are presented in this specification.
NoTa l —This specification is primarily a manufacturing and pur-
chasing specification. However, standard designs are included and the
criteria used to develop these designs are given in the Appendixes. The
successful performance of this product depends upon the proper
selection of the box section, bedding, backfill, and care that the
installation conforms to the construction specifications. The owner of
the precast reinforced concrete box sections specified herein is cautioned
that he must properly correlate the loading conditions and the field
requirements with the box section specified and provide for inspection
at the construction site.
Nora 2— Specification C 850 is to be used for box sections with less
than 2 It of cover subjected to highway loading.
2. Referenced Documents
2.1 ASTM Standards:
A 82 Specification for Steel Wire, Plain, for Concrete
Reinforcement
A 185 Specification for Steel Welded Wire Fabric, Plain,
for Concrete Reinforcement
A 496 Specification for Steel Wire, Deformed, for Con-
crete Reinforcement
A 497 Specification for Steel Welded Wire Fabric, De-
formed, for Concrete Reinforcement
C 31 Practice for Making and Curing Concrete Test
Specimens in the Field
C 33 Specification for Concrete Aggregates'
C 39 Test Method for Comprehensive Strength of Cylin-
drical Concrete Specimens
C 150 Specification for Portland Cement°
C 309 Specification for Liquid Membrane- Forming Com-
pounds for Curing Concrete
C 497 Test Methods for Concrete Pipe, Manhole Sections,
or Tiles
A This specification is under the jurisdiction of ASTM Committee C -13 on
Concrete Pipe and is under the direct responsibility of Subcommittee C13.07 on
Acceptance Specifications and Precast Concrete Box Sections.
Current edition approved July 15, 1994. Published September 1994. Originally
published as C 789 - 74. cast previous edition C 789 - 90.
s Annual Book of ASTM Standards, Vol 01.04.
s Annual Book of ASTM Standards. Vol 04.02.
• Annual Book of ASTM Standards, Vol 04.01.
3 Annual Book of ASTM Standards. Vol 04.05.
C 595 Specification for Blended Hydraulic Cements°
C 618 Specification for Fly Ash and Raw or Calcined
Natural Pozzolan for Use as a Mineral Admixture in
Portland Cement Concrete
C 822 Terminology Relating to Concrete Pipe and Related
Products
C 850 Specification for Precast Reinforced Concrete Box
Sections for Culverts, Storm Drains, and Sewers with
Less Than 2 ft of Cover Subjected to Highway
Loadings
2.2 AASHTO Standard.•
Specifications for Highway Bridges, 1973 Editionb
2.3 ACJ Code. 7
ACI 318 -71 Building Code, 1971 edition
3. Terminology
3.1 Definitions —For definitions of terms relating to con-
crete pipe, see Terminology C 822.
4. Types
4.1 Precast reinforced concrete box sections manufac-
tured in accordance with this specification shall be of three
types identified in Tables 1, 2, and 3 and shall be designated
by type, span, rise, and design earth cover.
S. Basis of Acceptance
5.1 Acceptability of the box sections produced in accor-
dance with Section 7 shall be determined by the results of the
concrete compressive strength tests described in Section 10,
by the material requirements described in Section 6, and by
inspection of the finished box sections.
5.2 Box sections shall be considered ready for acceptance
when they conform to the requirements of this specification.
6. Materials
6.1 Reinforced Concrete —The reinforced concrete shall
consist of cementitious materials, mineral aggregates and
water, in which steel has been embedded in such a manner
that the steel and concrete act together.
6.2 Cementitious Materials:
6.2.1 Cement — Cement shall conform to the require-
ments for portland cement of Specification C 150 or shall be
portland blast- furnace slag cement or portland-pozzolan
cement conforming to the requirements of Specification
6 Available from American Association for State Highway Transportation
Officials, 444 N Capitol, Washington, DC 20001.
r Available from the American Concrete Institute, P.O. Box 19150. Detroit. MI
48219.
164
4,U! C 655M
Section 4. Each certification so furnished shall be signed by
an authorized agent of the manufacturer.
17. Product Marking
17.1 The following information shall be legibly marked
on each section of pipe:
17.1.1 The pipe design strength shall be indicated by the
0.3 -mm crack D -load designated in 5.1.2 followed by the
capital letter D and specification designation,
17.1.2 Date of manufacture,
17.1.3 Name or trademark of the manufacturer,
17.1.4 Plant identification, and
17.1.5 One end of each section of pipe designed to bf
installed with a particular axis of orientation shall be clearly
marked during the process of manufacturing or immediately
thereafter on the inside and outside of opposite walls on the
vertical axis or shall be designated by location of lift holes.
17.2 Markings shall be indented on the pipe section or
painted thereon with water proof paint.
18. Keywords
18.1 concrete pipe - reinforced; culvert; D load; sewer
pipe; storm drains; three edge bearing strength
APPENDIX
(Nonmandatory Information)
XI. EXAMPLE CALCULATION
X 1.1 As required by 10. 1, the acceptability of a lot of 520
sections of 1350 mm designated inside diameter pipe will be
determined in accordance with 4.1.1. The design strength
(0.3 -mm crack) D-load is specified as 62 N /linear metre per
millimetre of inside designated diameter (62 D pipe).
X 1.2 From the lot, randomly select a sample of five
specimens (n - 5) each 1.8 in long as shown in Table 2.
X1.3 Test the pipe and record the observed values of in
kilonewtons which produce the 0.3 -mm crack: 213.5 1,
144.57, 191.27, 200.17, and 180.15.
X 1.4 Since in this example X, is in kilonewtons, convert
the specification limit L (design strength D -load) to
kilonewtons by multiplying the D-load times the designated
inside diameter in millimetres times the pipe length in
metres, or
E X - 929.67 Z X - 175 593.26
(E X - ( 929.67) 2
-864 286.31
X - (EXdn)
X - ( 929.67/5)
X - 185.93 kN
X 1.8 The standard deviation, s, may be computed by
either Eq 1 or Eq 2. Since Eq 2 is a simpler form for
computation, this will be used. 11-1)
s- (Z X,=- (= ,C,)21n11(n- 1)
s (175 593.26 - 864 286.31/5)/(5 - 1)
s- 1 6 - 84.0
0
s - 26.15 kN
L - 62 x 1350 x 1.8 - 150.66 kN
X1.5 Since an observed value of the test loads (X, =
144.57) is less than the specification limit (L = 150.66),
compliance with the acceptability criteria must be deter-
mined in accordance with Section 10.
X 1.6 The following values for X and s must be computed:
X = average (arithmetic mean) of the observed values X,,
and
s = estimated standard deviation.
X 1.7 Calculate the values for X as follows:
X X,?
213.51
45 586.52
144.57
20 900.48
191.27
36 584.21
200.17
40 068.03
180.15
32 454.02
X1.9 The required minimum allowable arithmetic mean
X, is computed by Eq 6:
X,- L +1.10s
X, - 150.66 + 1.10 x 26.15
X, - 179.43 kN
Since the actual X of 185.93 kN is greater than the required
minimum allowable X, of 179.43 kN, the lot of pipe is
acceptable.
X 1.10 ASTM STP 15 D is a valuable source of informa-
tion regarding statistical procedures and simplified computa-
tional methods.
7 Manual on Presentation of Data and Control Chart Analysis. ASTM STP lS
D, ASTM, 1976.
The American Society for Testing and Materials takes no posalon respectirp the validity of any patent right* asserted in connection
with any item nwxkv d in this standard. Uses of this standard am expressly advised that drermaW= Of the vridlty of arty such
Patent rights. and the risk of k**V rnsunt of such rights, we wtkuly their own respornibility.
This standard is subject to revision r any time by the responsible tecMnieal convnrttee and must be nvnwed every five years and ` -
H net revaad, *utter feapprowd or witlthMM. Your cornnerts We invited safnr for Wdion of this standard or for addN&W rand**
and should be addfeated to ASTM Headquarters. Your comments wilt rocove careluf consideration r a Meting of the neporWble
fechn" uxnanittae, which you may a0end. N you feel thr your comet m haw not recwved a far heanng you should make your
views known to the ASTM Committee on Standards. 1916 Asa St., Phdadelphle. PA 19103.
Q C 789
MINIMUM LENGTH `
EQUAL TO SPACING
OF LONGITUDINAL
OUTSIDE LONGITUDINAL WIRES PLUS 2 IN. (Typ) SRE PIC. 3 AND 3A
THICKNESS (T) M _� FO R TYPICAL REIN -
RCF1
M= ARRANGEMrtfr
1 IN. COVER A•1
A� As2
i 1 IN. COVER
H
SYM ML- 1 IN.
SEE FIG. 2 FOR rRICAL I COVER
JOINT REINFORCE-- - RISE (R) AsI
MENS THIS AREA I
SPAN (S) I I (T)
THICKNESS
I IN
COVE cov Asa _ Ak
COVER
M
OUTSIDE LONGITUDINAL
NOTE t — The dmenslon M is the total of the IMoret(cal cut-off length plus the required anchorage.
NOTE 2 —The haunch dimension H is equal to the thickness T.
FIG. 1 Typical Box Section
..
C 595, except that the pozzolan constituent in the Type IP
portland pozzolan cement shall be fly ash and shall not
exceed 25 % by weight.
6.2.2 Fly Ash —Fly ash shall conform to the requirements
of Specification C 618, Class F or Class C.
6.2.3 Allowable Combinations of Cementitious Materi-
als —The combination of cementitious materials used in
concrete shall be one of the following:
6.2.3.1 Portland cement only.
6.2.3.2 Portland blast furnace slag cement only.
6.2.3.3 Portland pozzolan cement only.
6.2.3.4 A combination of pordand cement and fly ash
wherein the proportion of fly ash is between 5 and 25 % by
weight of total cementitious material (portland cement plus
fly ash).
6.3 Aggregates — Aggregates shall conform to Specifica-
tion C 33, except that the requirements for gradation shall
not apply.
6.4 Admixtures and Blends— Admixtures and blends may
be used with the approval of the owner.
6.5 Steel Reinforcement— Reinforcement shall consist of
welded wire fabric conforming to Specifications A 185 or
A 497.
7. Design
7.1 Design Tables —The box section dimensions, com-
pressive strength of the concrete, and reinforcement details
shall be as prescribed in Tables 1, 2, or 3 and Figs. 1, 2, and
3, subject to the provisions of Section 11. Table 1 sections
are designed for combined earth dead load and AASHTO
HS20 five load conditions. Table 2 sections are designed for
combined earth dead load and Interstate five load conditions
when the Interstate live loading exceeds the HS20 live
loading. Table 3 sections are designed for earth dead load
conditions only. Criteria used to develop Tables 1, 2, and 3
are given in Appendix X 1. For modifications to the designs
OUTER CAGE CIRCUMFERENTIAL RE-
INFORCEMENT AT FEMALE END.
1 IN.
COVER
k 6 IN. MIN
3 L1Y . UN - (TY0
2 IN. MAX.
LONGITUDINAL
REINFORCEMENT
1 IN.
COVER INNER CAGE - As1 (Top)
As3 (Bot.)
FIG. 2 Section A -A Top and Bottom Slab Joint Reinforcement
C 789
spacers used to position the reinforcement shall not be a
As1 cause for rejection.
7.4 Laps, Welds, and Spacing— Splices in the circumfer -___�
ential reinforcement shall be made by lapping. The overlap
4 d min Radiu measured between the outermost longitudinal wires of each
Top As2 fabric sheet shall not be less than the spacing of the
Bat. As longitudinal wires plus 2 in. If A,, is extended and con-
nected, welded splices shall be allowed in the connection. A
Aso may be lapped and welded at any location or connected by
welding at the corners to A and A The spacing center to
4 inches min,. center of the circumferential wires shall not be less than 2 in.
for 6 -inch 6 Abov e --� Li 1/2 inches max. nor more than 4 in. The spacing center to center of the
Wsl
for 4 & 5-inch Walls longitudinal wires shall not be more than 8 in.
FIG. 3 Detail Inner Reinforcement -
8. Joints
shown in Tables 1, 2, and 3 due to anticipated earth and
surcharge loads. different from those used to develop the
tables, see Appendix X2.
7.2 Modified and Special Designs —The manufacturer
may request approval by the owner of modified designs
which differ from the designs in Section 7; or special designs
for sizes and loads other than those shown in Tables 1, 2, and
3.
NoTe 3—The tabular designs in this specification were prepared
according to AASHTO Standard Specifications for Highway Bridges,
1973 Edition. The current Specifications for Highway Bridges allows
concrete shear stress criteria that differs from the 1973 criteria. The use
of current AASHTO concrete shear stress criteria shall be acceptable by
this specification for modified or special designs.
7.3 Placement of Reinforcement —The cover of concrete
over the circumferential reinforcement shall be l in., subject
to the provisions of Section 11. The inside circumferential
reinforcement shall extend into the male portion of the joint,
and the outside circumferential reinforcement shall extend
into the female portion of the joint. The clear distance of the
end circumferential wires shall be not less than 1 h in. nor
more than 2 in. from the ends of the box section. Reinforce-
ment shall be assembled utilizing any combination of single
or multiple layers of welded -wire fabric. A common rein-
forcement unit may be utilized for both A (or A and A
with the largest area requirement governing, bending the
reinforcement 90' at the corners and waiving the extension
requirements of Fig. 3. See Fig. 3A. The welded -wire fabric
shall be composed of circumferential and longitudinal wires
meeting the spacing requirements of 7.4 and shall contain
sufficient longitudinal wires extending through the box
section to maintain the shape and position of reinforcement.
The exposure of the ends of longitudinals, stirrups, and
Asl
4 d min.
Radius
2 Inches
max. Radius
Top As2
Bot. Asa
Side Aso
FIG. 3A Detail Option
8.1 The precast reinforced concrete box sections shall be
produced with finale and female ends. The ends shall be of
such design and the ends of the box sections so formed that
the sections can be laid together to make a continuous line of
box sections compatible with the permissible variations given
in Section 11.
8.2 Outer cage circumferential reinforcement as shown in
Figs. 1 and 2 shall be placed in the top and bottom slabs at
the female portion of the joint when A,, is not continuous
over the span. The minimum area of such reinforcement in
square inches per linear foot of box section length shall be
the same as the area specified for A, in Tables 1, 2, and 3.
9. Manufacture
9.1 Mixture —The aggregates shall be sized, graded, pro.
portioned, and mixed with such proportions of cementitious
materials and water as will produce a homogeneous concrete
mixture of such quality that the pipe will conform to the test
and design requirements of this specification. All concrete
shall have a water- cementitious materials ratio not exceeding
0.53 by weight. Cmentitious materials shall be as specified
in 6.2 and shall be added to the mix in a proportion not less
than 470 lb /yd unless mix designs with a lower cementitious
materials content demonstrate that the quality and perform-
ance of the pipe meet the requirements of this specification.
9.2 Curing —The box sections shall be cured for a suffi-
cient length of time so that the concrete will develop the
specified compressive strength in 28 days or less. Any one of
the following methods of curing or combinations thereof
may be used:
9.2.1 Steam Curing —The box sections may be low pres-
sure, steam -cured by a system that will maintain a moist
atmosphere.
9.2.2 Water Curing —The box sections may be water -
cured by any method that will keep the sections moist.
9.2.3 Membrane Curing —A sealing membrane con-
forming to the requirements of Specification C 309 may be
applied and shall be left intact until the required concrete
compressive strength is attained. The concrete temperature
at the time of application shall be within 107 of the
atmospheric temperature. All surfaces shall be kept moist
prior to the application of the compounds and shall be damF
when the compound is applied.
9.3 Forms —The forms used in manufacture shall be
sufficiently rigid and accurate to maintain the box section
dimensions within the permissible variations given in Sec-
Q C 789
_, Io
tion 11. All casting surfaces shall be of smooth nonporous
material.
9.4 Handling — Handling devices or holes shall be per-
mitted in each box section for the purpose of handling and
laying.
10. Physical Requirements
10.1 Type of Test Specimen— Compression tests for deter-
mining concrete compressive strength may be made on
either standard rodded concrete cylinders or concrete cylin-
ders compacted and cured in like manner as the box
sections, or on cores drilled from the box section.
10.2 Compression Testing of Cylinders:
10.2.1 Cylinders shall be obtained and tested for compres-
sive strength in accordance with the provisions of Practice
C 31 and Test Method C 39, except that the cylinders may be
prepared by. methods comparable to those used to consoli-
date and cure the concrete in the actual box section
manufactured. Cylindrical specimens of sizes other than 6 in.
by 12 in. may be used provided all other requirements of
Practice C 31 are met. If the concrete is of a consistency too
still' for compaction by rodding or internal vibration, the
following alternative method may be used: Bolt a mold to
the top of a vibrating table or to the actual form being used
for manufacture. External vibration shall be applied with a
frequency of at least 800 vibrations per minute. Place
concrete in three equal lifts within the cylinder. During
vibration, place a cylindrical hammer on the surface of each
lift with the hammer to be 1 /4 inch less in diameter than the
inside diameter of the mold and of a weight to create a
pressure of 0.353 psi on the surface of the concrete. Continue
vibration until cement paste begins to ooze up around the
bottom edge of the hammer. Repeat this procedure until the
mold is filled. Cylinders shall be exposed to the same curing
conditions as the manufactured box sections and shall
remain with the sections until tested.
10.2.2 Prepare not less than five test cylinders from each
day's production of the lot of box sections.
10.2.3 Acceptability on the Basis of Cylinder Test Results:
10.2.3.1 When the average compressive strength of all
cylinders tested is equal to or greater than the design concrete
strength, and not more than 10 % of the cylinders tested
have a compressive strength less than the design concrete
strength, and no cylinder tested has a compressive strength
less than 80 % of the design concrete strength, then the lot
shall be accepted.
10.2.3.2 When the compressive strength of the cylinders
tested does not conform to the acceptance criteria stated in
10.2.3.1, the acceptability of the lot shall be determined in
accordance with the provisions of 10.3.
10.3 Compression Testing of Cores:
10.3.1 Cores shall be obtained and tested for compressive
strength in accordance with the provisions of Test Methods
C 497.
10.3.2 One core shall be cut from a section selected at
random from each group of 15 box sections or fraction
thereof of a single size from each continuous production run.
10.3.3 Acceptability by Core Tests:
10.3.3.1 The compressive strength of the concrete in each
group of box sections defined in 10.1 is acceptable when the
core test strengths are equal to or greater than the design
concrete strength, r
10.3.3.2 When the compressive strength of the core tested
is less than the design concrete strength, the box section from
which that core was taken may be recored. When the
compressive strength of the recore is equal to or greater than
the design concrete strength, the compressive strength of the
concrete in that group of box sections is acceptable.
10.3.3.3 When the compressive strength of any recore is
less than the design concrete strength, the box section from
which that core was taken shall be rejected. Two box sections
from the remainder of the group shall be selected at random
and one core shall be taken from each. If the compressive
strength of both cores is equal to or greater than the design
concrete strength, the compressive strength of the remainder
of that group of box sections is acceptable. If the compressive
strength of either of the two cores tested is less than the
design concrete strength, the remainder of the group of box
sections shall be rejected or, at the option of the manufac-
turer, each box section of the remainder of the group shall be
cored and accepted individually, and any of these box
sections that have cores with less than the design concrete
strength shall be rejected.
10.4 Plugging Core Holes —The core holes shall be
plugged and sealed by the manufacturer in a manner such
that the box section will meet all of the test requirements of
this specification. Box sections so sealed shall be considered
as satisfactory for use.
10.5 Test Equipment —Every manufacturer furnishing
box sections under this specification shall furnish all facilities
and personnel necessary to carry out the tests required.
11. Permissible Variations
11.1 Internal Dimensions —The internal dimensions shall
not vary more than 1 % from the design dimensions. The
haunch dimensions shall not vary more than 'Ain. from the
design dimensions.
11.2 Slab and Wall Thickness —The slab and wall thick-
ness shall not be less than that shown in the design by more
than 5 % or 3 /16 in., whichever is greater. A thickness more
than that required in the design shall not be a cause for
rejection.
11.3 Length of Opposite Surfaces— Variations in laying
lengths of two opposite surfaces of the box section shall not
be more than 1 A in. /ft of internal span, with a maximum of
s/s in. for all sizes through 7 ft internal span, and a maximum
of 3 /4 in. for internal spans greater than 7 ft, except where
beveled ends for laying of curves are specified by the owner.
11.4 Length of Section —The underrun in length of a
section shall not be more than 1 A in. /ft of length with a
maximum of 1 /: in. in any box section.
11.5 Position of Reinforcement —The maximum variation
in the position of the reinforcement for 5 -in. or less slab and
wall thicknesses shall be :0 /s in., and for greater than 5 -in.
slab and wall thicknesses shall be t 1 /2 in. In no case,
however, shall the cover over the reinforcement be less than
s/a in., as measured to the internal surface or the external
surface. The preceding minimum cover limitation does not
apply at the mating surfaces of the joint.
11.6 Area of Reinforcement —The area of steel reinforce-
ment shall be the design steel areas as shown in Tables 1, 2,
or 3. Steel areas greater than those required shall not be cause
9b c 789
for rejection. The permissible variation in diameter of any
wire in finished fabric shall conform to the tolerances
prescribed for the wire before fabrication by either Specifica-
tions A 82 or A 496 as applicable.
12. Repairs
12.1 Box sections may be repaired, if necessary, because
of imperfections in manufacture or handling damage and
will be acceptable if, in the opinion of the owner, the
repaired box section conforms to the requirements of this
specification.
13. Inspection
13.1 The quality of materials, the process of manufacture,
and the finished box sections shall be subject to inspection by
the owner. .
14. Rejection
14.1 Box sections shall be subject to rejection on account
of failure to conform to any of the specification require-
ments. Individual box sections may be rejected because of
any of the following:
14.1.1 Fractures or cracks passing through the wall, except
for a single end crack that does not exceed the depth of the
joint,
14.1.2 Defects that indicate mixing and molding, not in
compliance with 9. 1, or honeycombed or open texture that
would adversely affect the function of the box sections,
14.1.3 The ends of the box sections are not normal to th
walls and center line of the box section, within the limits of'
variations given in Section 11, except where beveled ends are
specified, and
14.1.4 Damaged ends, where such damage would prevent
making a satisfactory joint.
15. Product Marking
15.1 The following information shall be legibly marked
on each box section by indentation, waterproof paint, or
other approved means.
15. 1.1 Box section span, rise, table number, maximum
and ntinimum, design earth cover, and specification designa-
tion,
15.1.2 Date of manufacture,
15.1.3 Name or trademark of the manufacturer, and
15.1.4 Each section shall be clearly marked by indenta-
tion on either the inner or outer surface during the process of
manufacture so that the location of the top will be evident
immediately after the forms are stripped. In addition, the
word "top" shall be lettered with waterproof paint on the
inside top surface.
16. Keywords
16.1 concrete box — precast; culvert
4ffO C 789
TABLE 1 Design Requirements for Precast Concrete Box Sections Under Earth Dtrad and H$20 Live Load ConditionsA
Nora 1- 4080 earth covers and reinforcement areas are be an the weight of a column of earth over the width of the box section as defined In Appendix Xt. See
Appendix X2 for modifications to reinforcement areas for other earth load conditions.
Nora 2- Conc d esi g n strength 5000 pal.
Design Earth
M. min, in.
ClrctxnfemdW Reinforcement Areas
Design Earth
M, min. In.
Ctraxnferentld Reinforcement A
Cover. tt
A., A.
A
A.,
Cave. ft A
A.,
Ana
A.
A.•
3 It by 2 It by 4 Imc
5Itby3itby6in.c
2
17
0.19 0.20
0.21
0.10
2
23
0.26
0.28
0.23
0.14
3
15
0.10 0.11
0.11
0.10
3
21
0.17
0.18
0.18
0.14
4 to 8
15
0.10 0.10
0.10
0.10
4
21
0.14
0.15
0.15
0.14
10
15
0.10 0.11
0.11
0.10
5
20
0.14
0.14
0.15
0.14
12
14
0.10 0.13
0.13
0.10
6
20
0.14
0.15
0.15
0.14
14
14
0.11 0.14
0.14
0.10
8
20
0.14
0.16
0.16
0.14
18
14
0.12 0.16
0.16
0.10
10
20
0.15
0.16
0.19
0.14
18
14
0.13 0.17
0.18
0.10
12
20
0.17
0.20
0.21
0.14
20
14
0.14 0.19
0.19 -
-- 0.10 --
- 14
20
0.19
023
0.23
0.14
16
19
021
0.26
0.26
0.14
3 It by 3 It by 4 kt a
18
19
023
028
029
0.14
2
27
0.15 024
025
0.10
3
20
0.10 0.13
0.14
0.10
4 to 6
17
0.10 0.10
0.10
0.10
5 it by 4 It by
6 ln.
8
15
0.10 0.11
0.11
0.10
10
15
0.10 0.12
0.13
0.10
12
15
0.10 0.14
0.14
0.10
2
28
023
0.32
0.27
0.14
14
15
0.10 0.15
0.16
0.10
3
23
0.15
0.20
021
0.14
16
15
0.10 0.17
0.18
0.10
4 to 6
22
0.14
0.16
0.17
0.14
18
15
0.10 0.19
0.19
0.10
8
20
0.14
0.17
0.18
0.14
20
15
0.11 021
021
0.10
10
20
0.14
020
021
0.14
12
20
0.14
022
023
0.14
4 It b y 2 ft by 5 h. 0
14
20
0.16
025
026
0.14
2
19
026 022
020
0.12
16
19
0.18
0.28
029
0.14
3
18
0.15 0.13
0.13
0.17
18
19
0.20
0.31
0.31
0.14
4 to 8
18
0.12 0.12
0.12
0.17
10
17
0.13 0.13
0.14
0.12
12
17
0.15 0.15
0.15
0.12
5 ft by 5 it by
6 in.
14
17
0.17 0.17
0.17
0.19
16
18
17
17
0.19 0.19
0.21 021
0.19
021
0.12
0.12
2
41
0.20
0.35
0.29
0.14
3
29
0.14
0.22
0.23
0.14
4 h by 3 it by 5 l n.c
4
25
0.14
0.18
0.19
0.14
2
22
021 0.27
0.24
0.12
5
24
0.14
0.17
0.18
0.14
3
19
0.13 0.16
0.16
0.12
6
22
0.14
0.17
0.18
0.14
4
18
0.12 0.13
0.13
0.12
8
22
0.14
0.18
0.19
0.14
5
18
0.12 0.12
0.13
0.12
10
21
0.14
021
0.22
0.14
8
17
0.12 0.12
0.13
0.12
12
21
0.14
023
024
0.14
6
17
0.12 0.14
0.14
0.12
14
21
0.14
0.26
0.27
0.14
10
17
0.12 0.15
0.16
0.12
16
21
0.16
0.29
0.30
0.14
12
17
0.12 0.17
0.18
0.12
18
20
0.17
0.32
0.33
0.14
14
17
0.13 0.20
020
0.12
16
17
0.15 0.22
022
0.12
18
17
0.16 0.24
02 4
0.12
6 ft by 3 it by
7 In.c
4 it by 4 it by 5 l n.c
2
34
0.18 0.30
028
0.12
2
29
0.30
0.29
022
0.17
3
24
0.12 0.18
0.18
0.12
3
24
021
0.19
0.18
0.17
4
21
0.12 0.14
0.15
0.12
4
24
0.18
0.17
0.17
0.17
5
20
0.12 0.13
0.14
0.12
5
24
0.17
0.17
0.17
0.17
6
19
0.12 0.14
0.14
0.12
6
23
0.17
0.17
0.17
0.17
8
18
0.12 0.15
0.15
0.12
8
23
0.17
0.18
0.18
0.17
10
18
0.12 0.16
0.17
0.12
10
23
020
0.20
0.21
0.17
12
18
0.12 0.19
0.19
0.12
12
23
023
0.23
024
0.17
14
18
0.12 0.21
021
0.12
14
23
0.26
0.26
0.26
0.17
18
18
0.12 023
0.24
0.12
16
23
028
0.29
0.29
0.17
18
17
0.14 0.25
0. 26
0.12
18
23
0.31
0.32
0. 32
0.170
Q C 789
TABLE 1 Cont inued
Deso Earth
Cover' ftA
M, min, h.
ChxxttferontW
A
Rehtofcwmt Meea'
Aa Aa Ai4
Deso Earth
Cover, ftA
M. min. in.
Chx+mfomtW ReWorr ement M ms .
As, Aa Aa A.,
33
0.17
6 ft by 4 ft by 7 Imc
025
0.17
4
29
7ftby6ftby8h.0
0.22
023
0.17
2
28
0.26
0.33
026
0.17
2
38
0.24
0.39
0.31
0.19
3
25
0.18
022
021
0.17
3
31
0.19
027
026
0.19
4
24
0.17
0.19
0.19
0.17
4
29
0.19
024
025
0.19
5
23
0.17
0.18
0.19
0.17
5
28
0.19
023
025
0.19
6
23
0.17
0.18
0.19
0.17
6
27
0.19
024
0.25
0.19
8
23
0.17
0.20
0.21
0.17
8
26
0.19
026
027
0.19
10
22
0.18
023
024
0.17
10
26
0.19
029
0.30
0.19
12
22
020
026
026
0.17
12
26
020
0.33
0.34
0.19
14
22
022
029
0.30
0.17
14
25
022
0.36
0.38
0.19
16
22
024
0.32
0.33
0.17
16
25
025
0.40
0.42
0.19
18
22
027
0.35
0.36
0.17
18
25
027
0.44
0.
0.19
7ftby7
6ttby5ftby7h.O
2
55
022
0.42
0.33
0.19
2
33
024
0.36
029
0.17
3
38
0.19
0.29
027
0.19
3
27
0.17
024
023
0.17
4 to 6
33
0.19
0.25
027
0.19
4 to 6
25
0.17
020
021
0.17
8
28
0.19
027
029
0.19
8
23
0.17
021
022
0.17
10
27
0.19
0.30
0.32
0.19
10
23
0.17
024
025
0.17
12
27
0.19
0.34
0.36
0.19
12
23
0.17
027
029
0.17
14
27
021
0.37
0.39
0.19
14
23
0.19
0.31
0.32
0.17
D
16
27
0.23
0.41
0.43
0.19
16 22 021 0.34 0.35 0.17
18 22 023 0.37 0.39 0.17
6ft by61tby71n.
2
48
022
0.39
0.31
0.17°
3
33
0.17
028
025
0.17
4
29
0.17
0.22
023
0.17
5
27
0.17
021
022
0.17
8
26
0.17
021
022
0.17
8
25
0.17
022
024
0.17
10
24
0.17
025
027
0.17
12
24
0.17
028
0.30
0.17
14
24
0.17
0.32
0.33
0.17
16
24
0.19
0.35
0.37
0.17
18
23
021
0.38
0.40
0.1 7 0
4
30
7ftby4ft by8h.
0.29
029
0.19
2
32
0.30
0.34
025
0.19
3
27
021
023
021
0.19
4
27
0.19
020
020
0.19
5
26
0.19
020
021
0.19
6
26
0.19
020
021
0.19
8
26
020
022
023
0.19
10
25
023
025
026
0.19
12
25
025
029
0.29
0.19
14
25
028
0.32
0.33
0.19
16
25
0.31
0.38
0.38
0.19
18
25
0.34
0.39
0.40
0.19
7ftby5hby81n.
2
32
027
0.37
028
0.19
3
28
0.19
0.26
0.23
0.19
4 to 6
27
0.19
022
023
0.19
8
26
0.19
0.24
025
0.19
10
25
020
0.27
029
0.19
12
25
022
0.31
0.32
0.19
14
25
025
0.35
0.36
0.19
16
25
027
0.38
0.40
0.19
19
25
0.30
0.42
0.43
0.19
2
35
8ftby4ftby8h.a
0.43
0.32
2
34
0.37 0.40
029
0.19
3
31
027 028
0.24
0.19
4
28
025 0.25
024
0.19
5
28
026 025
026
0.19
6
28
026 026
026
0.19
8
27
028 0.28
029
0.19
10
27
0.32 0.32
0.33
0.19
12
27
0.36 0.36
0.37
0.19
14
27
0.40 0.41
0.42
0.19
8ft by6ftby8h.
aft by5ftb
2
2
35
0.34
0.43
0.32
0.19°
3
31.
0.25
0.31
027
0.19
4
28
023
027
027
0.19
5
28
024
027
0.29
0.19
6
27
024
028
029
0.19
8
27
028
0.30
0.32
0.19
10
27
0.29
0.35
0.38
0.19
12
27
0.32
0.39
0.41
0.19
8ft by6ftby8h.
2
36
0.31
0.46
0.35
0.19
3
31
023
0.33
029
0.19
4
30
0.22
0.29
029
0.19
5
29
023
0.29
0.31
0.19
6
28
022
0.30
0.31
0.19
8
27
024
0.32
0.34
0.19
10
27
027
0.37
0.39
0.19
12
27
0.30
0.42
0.43
0.19
Bnby7ft by8
2
41
0.28
0.49
0.38
0.19
3
35
022
0.35
0.32
0.19
4
32
020
0.31
0.31
0.19
5
31
021
0.31
0.33
0.19
6
30
021
0.31
0.34
0.19
8
29
0.22
0.34
0.36
0.19
10
28
025
0.38
0.41
0.19
12
28
0.28
0.43
0.46
0.190
@0 C 789
TABLE 1 Continued
Design Earth
Cover. ftA
M. min, In.
Ckmaterentlai ReInfacanent Mesa•
A s , AA, A. A,.
Design Earth
Cover. ft A
M. min. In.
CYaxn1wentld R*ftmetnent Mean
An Aa A.t Aw
8Itby8ftby8in.
10It by5ftby10ln.c
2
61
026
0.51
0.40
0.19
2
41
0.38
0.43
0.31
0.24
3
41
020
0.37
0.34
0.19
3
38
0.30
0.32
027
0.24
4
36
0.19
0.32
0.33
0.19
4
35
029
0.30
028
0.24
5
34
020
0.32
0.35
0.19
5
34
0.31
0.30
0.30
0.24
6
32
020
0.33
0.36
0.19
6
33
0.33
0.32
0.33
0.24
8
31
021
0.35
0.38
0.19
8
33
0.35
0.35
0.36
0.24
10
30
023
0.40
0.43
0.19
10
33
0.40
0.40
0.41
0.24
12
29
026
0.44
0.48
0.19
12
33
0.45
0.45
0.46
0.24
14
33
0.50
0.50
0.51
0.24
9 ft by 5 ft by
9 i n.0
10 it by 6 ft by
10 In.c
2
3
38
34
0.36
028
0.43
0.32
0.31
027
0.220
0.220
2
41
0.35
0.46
0.34
0.24
4
31
026
028
027
0.220
3
37
029
0.35
0.30
0.24
5
31
0.28
0.29
0.29
0.220
4
34
027
0.32
0.30
0.24
6
30
029
0.30
0.31
0.220
5
33
029
0.33
0.33
0.24
8
30
0.30
0.32
0.34
0.220
6
8
33
33
0.31
0.33
0.34
• 0.37
0.36
0.39
0.24
0.24
10
12
30
30
0.34
0.38
0.37
0.42
• 0.39
0.43
0.220
0.220
10
32
0.37
0.42
0.44
0.24
14
29
0.43
0.47
0.48
0.220
12
14
32
32
0.41
0.46
0.48
0.53
0.50
0.55
0.24
0.2 4 0
9 f by 8ftby9h.
c
10 ft by7ttby10h.c
2
38
0.33
0.46
0.34
0.22
2
42
0.32
0.49
0.36
0.24
3
34
026
0.34
029
0.220
3
38
027
0.37
0.32
0.24
4
32
024
0.31
0.29
0.220
4
35
026
0.34
0.32
0.24
5
31
026
0.31
0.32
0.22
5
34
027
0.35
0135
0.24
6
30
027
0.32
0.34
0.22
6
34
029
0.36
0.38
0.24
8
30
028
0.35
0.37
0.220
6
33
0.31
0.39
0.42
0.24
10
30
0.31
0.40
0.41
0.220
10
33
0.34
0.45
0.47
0.24
12
29
0.35
0.45
0.47
0.220
12
32
0.38
0.50
0.52
0.24
9 hby7ttby9he
lOHby8ttby10Inc
2
41
0.30
0.49
0.37
0.22
2
45
0.31
0.52
0.39
0.24
3
36
024
0.36
0.32
0.22
3
40
026
0.39
0.34
0.24
4
33
023
0.32
0.32
0.220
4
37
0.25
0.36
0.35
0.24
5
32
0.24
0.33
0.34
0.22
5
36
026
0.37
0.38
0.24
6
31
025
0.34
0.36
0.22
g
35
027
0.38
0.41
0.24
8
31
026
0.37
0.39
0.220
8
34
0.29
0.41
0.44
0.24
10
30
029
0.42
0.44
0.220
10
33
0.32
0.47
0.50
0.24
12
30
0.33
0.47
0.49
0.22
12
33
0.38
0.52
0.55
0.2 4 0
9ft by8ftby9h.
10ftby9tt by10h.
2
46
028
0.51
0.39
0.22
2
51
029
0.54
0.42
0.24
3
39
023
0.38
0.34
0.22
3
44
0.24
0.41
0.37
0.24
4
38
0.22
0.34
0.34
0.22
4
40
0.24
0.37
0.37
024
5
34
023
0.35
0.37
0.22
5
38
025
0.38
0.40
0.24
6
33
024
0.35
0.38
0.22
6
37
020
0.40
0.43
0.24
8
32
025
0.38
0.41
0.22
8
36
028
0.43
0.46
0.24
10
31
028
0.43
0.46
0.22
10
35
0.31
0.48
0.52
0.24
12
31
0.31
0.49
0.52
0.22
12
34
0.34
0.54
0.58
0.24
9ftby9ft by9in
10ft by10ftby10h.
2
68
027
0.54
0.42
0.22
2
75
029
0.56
0.44
0.24
3
45
0.22
0.40
0.36
0.22
3
50
0.24
0.43
0.39
0.24
4
41
0.22
0.36
0.36
0.22
4
45
0.24
0139
0.39
0.24
5
38
0.22
0.36
0.39
0.22
5
42
0.24
0.40
0.42
0.24
6
36
023
0.37
0.40
0.22
8
40
025
0.41
0.45
0.24
8
34
0.24
0.40
0.43
0.22
8
38
027
0.44
0.48
0.24
10
33
026
0.45
0.48
0.22
10
37
0.30
0.50
0.54
0.24
12
33
0.29
0.50
0.54
0 .22 0
12
38
0.33
0.55
0.60
0.24
1,1
4D C 789
TABLE 1 Cont inued
Design Earth
M. min, In.
Cinmolerentld Reinforcement Areasa
Design Earth
M. min. In.
Circumferential Reinforcement Arease
Cover. ftA
A,, A.2
Au
A.4
Cover. ftA
A,,
A,
A,
A,4
11It by4ftby11irt.c
12 ft by 4 It by 12 in. c
2
45
0.44 0.40
0.27
0.26
2
50
0.46
0.41
0.29
0.29
3
43
0.35 0.30
0.26°
0.26
3
47
0.38
0.31
0.29
0.29
4
42
0.35 0.28
0.26
026
4
45
0.38
0.29
0.29
0.29
5
39
0.37 0.29
0.28
0.26
5
43
0.41
0.30
0.29
0.29
6
38
0.39 0.30
0.30
0.26
6
42
0.43
0.31
0.31
0.29
8
38
0.43 0.33
0.34
0.26
8
41
0.49
0.35
0.36
0.29
10
37
0.49 0.38
0.39
0.26
10
41
41
0.55
0.62
0.40
0.45
0.41
0.46
0.29
0.29
12
14
37
37
0.55 0.43
0.62 0.48
0.44
0.49
0.26
026
12
14
41
0.70
0.50
0.51
0.29
16
37
0.69 0.53
0.54
026
16
41
0.78
0.55
0.57
0.29
11 ft by6It by11in.c
12 ft by 6 ft by 12 in.c
2
44
0.37 0.46
0.33
0.26
2
47
0.39
0.47
0.33
0.29
3
41
0.31 0.35
0.30
0.26
3
44
0.33
0.36
0.30
0.29
4
38
0.30 0.33
0.30.
0.26
4
41
0.33
0.34
0.31
0.29
5
36
0.32 0.34
0.33
0.26
5
6
39
39
0.35
0.38
0.35
0.37
0.34
0.37 •
0.29
0.290
6
8
36
36
0.34 0.35
0.37 0.39
0.36
0.41
0.26
0.26
8
39
0.42
0.41
0.43
0.29
10
35
0.42 0.44
0.46
0.26
10
12
39
38
0.47
0.53
0.47
0.53
0.49
0.55
0.29
0.29
12
14
35
35
0.46 0.50
0.52 0.56
0.52
0.58
026
0.26
14
38
0.59
0.59
0.61
0.29
16
35
0.57 0.62
0.64
0.26
16
38
0.65
0.65
0.67
0.29
11 ft by8It by11ln.0
12ft by8It by12in.c
2
46
0.33 0.51
0.38
0.26
2
48
44
0.35
0.31
0.52
0.40
0.38
0.35
0.29
0.29
3
4
41
39
028 0.39
027 0.36
0.34
0.35
0.26
0.26
3
4
41
0.30
0.38
0.36
029
5
37
029 0.38
0.38
0.26
5
40
39
0.32
0.34
0.39
0.41
0.39
0.42
0.29
0.29
6
8
37
36
0.30 0.39
0.33 0.43
0.41
0.46
0.26
0.26
6
8
39
0.38
0.46
0.48
029.
10
36
0.37 0.48
0.51
0.26
10
38
38
0.42
0.46
0.52
0.58
0.55
0.61
0.29
0.29
12
35
35
0.41 0.54
0.45 0.61
0.57
0.64
026
0.26
12
14
38
0.52
0.
0.68
0.29
14
12nbytohby12Imc
11hby10nby111n.c
2
56
0.30 0.55
0.43
0.26
2
3
55
48
0.33
0.29
0.56
0.44
0.43
0.39
0.29
0.29
3
4
48
44
0.26 0.42
0.26 0.39
0.38
0.38
0.26
0.26
4
44
0.29
0.41
0.40
0.29
5
42
0.26 0.40
0.42
0.26
5
43
0.29
0.32
0.43
0.44
0.43
0.47
0.29
0.29
6
8
40
39
0.28 0.42
0.30 0.45
0.45
0.49
0.26
0.26
6
8
42
40
0.35
0.49
0.53
0.29
10
38
0.34 0.51
0.55
0.26
10
40
39
0.38
0.42
0.55
0.61
0.59
0.66
0.29
0.29
12
14
37
37
0.37 0.57
0.41 0.64
0.62
0.68
0.26
0.26
12
14
39
0.47
0.68
0.73
0.29
11 It by11 ft by11 in.c
12ttby12ftby12Inc
2
82
0.30 0.57
0.45
0.26
2
89
0.32
0.29
0.60
0.47
0.48
0.43
0.29
0.29
3
55
026 0.44
0.26 0.41
0.40
0.40
026
0.26
3
4
60
53
0.29
0.44
0.43
0.29
4
5
48
46
0.26 0.42
0.43
026
5
50
0.29
0.45
0.47
0.50
0.29
0.29
6
44
027 0.43
0.47
0.26
6
8
48
45
0.29
0.33
0.47
0.51
0.57
0.29
8
10
41
40
029 0.46
0.33 0.52
0.51
0.57
0.26
0.26
10
44
0.36
0.57
0.63
0.29
12
39
0.36 0.58
0.63
0.26
12
43
42
0.40
0.44
0.64
0.70
0.70
0.77
0.29
0.29
14
39
0.40 0.64
0.70
0.26
14
" The design earth cover Indicated is the height of fig above the top of the box section. Design requirements ere based on the Material and soil properON. loading data.
and typical section as 4tcr,rded In Appendix X1. For dtemative or special designs see 7.2.
those locations which are Indicated on the
typical section
ir"Wad In Appendix X1.
a Design steel arse in square inches per Wow foot of box section
at
Honzontd Span in feet) by (Interior Vertical Rise In feet) by
(Wag and Slab Thldw*33
c The top section
designation,
for example. 31t by 2
It by 4 In..
indicates (Interior
in itches).
0 MWrruun
practical steel area is 3ped6ed•
Q c 789
TABLE 2 Design Requirements for Precast Concrete Box Sections Under Earth Dead and interstate Live Load Conditions"
Nois 1 - 4ee0 sum covers snd rWnb=mwlt was we based an the weight of a cakxrin of earth over the width of the box section u defined ki Appvdix XI. See
Appendlx X2 for rtad*Adom to rehftowrat arses for other wM tad condldons.
0.32
0.27
2
27
0.15 0.24
NoTa 2 -4mrow design stnrpth 5000 pd.
0.10
3
'20
0.10 0.13
0.14
EwM Craxeiersntw R4hkwcemsnt Amass
peso �
M, min, h
CirWnfareneal Rehforewmit Areas•
Cover, , ftA M ' ' �' A., Ap A A
COW. ftA
8
A'1 A.a
Aa
A"
3itby2nby4Imc
10
15
5ftby3ftby8hQ
0.13
0.10
2 17 0.19 0.20 0.21 0.10
2
23
0.26 0.28
0.24
0.14
3 15 0.10 0.11 0.11 0.10
3
21
0.17 0.18
0.18
0.14
4 to 8 15 0.10 0.10 0.10 0.10
4
21
0.14 0.15
0.15
0.14
10 14 0.10 0.11 0.12 0.10
5
20
0.14 0.14
0.15
0.14
12 14 0.10 0.13 0.13 0.10
6
20
0.14 0.15
0.15
0.14
14 14 0.10 0.14 0.14 0.10
8
20
0.14 0.17
0.17
0.14
18 14 0.12 0.16 0.16 0.10
10
20
0.16 0.16
0.19
0.14
18 14 0.13 0.18 0.18 0.10
12
20
0.17 0.21
0.21
0.14
20 14 0.15 0.19 0.19 0.10
14
20
0.19 0.23
0.23
0.14
0.12
16
19
0.22 0.26
0.26
0.14
18 19 0.24 0.29 029 0.1
5ftby by6h.
2
28
3 ft by 3 ft by 4 Kc
0.32
0.27
2
27
0.15 0.24
0.25
0.10
3
'20
0.10 0.13
0.14
0.10
4 to 6
18
0.10 0.10
0.11
0.10
8
15
0.10 0.11
0.12
0.10
10
15
0.10 0.13
0.13
0.10
12
15
0.10 0.14
0.14
0.10
14
15
0.10 0.15
0.16
0.10
16
15
0.10 0.17
0.18
0.10
16
15
0.10 0.19
0.20
0.10
20
15
0.11 0.21
0.21
0.10
0.13
0.20
4ftby211 by5h.
0.12
16
2
19
0.25 0.22
0.20
0.12
3
18
0.15 0.13
0.13
0.12
4106
18
0.12 0.12
0.12
0.12
6
17
0.13 0.12
0.12
0.12
10
17
0.14 0.14
0.14
0.12
12
17
0.15 0.15
0.15
0.12
14
17
0.17 0.17
0.17
0.12
16
17
0.19 0.19
0.19
0.12
18
17
0.21 0.21
0.2
0.12
18 19 0.24 0.29 029 0.1
5ftby by6h.
2
28
4ftby3Itby5IMO
0.32
0.27
2
22
0.21
0.27
0.24
0.12
3
19
0.13
0.16
0.16
0.12
4
/8
0.12
0.13
0.13
0.12
5
18
0.12
0.12
0.13
0.12
6
17
0.12
0.13
0.13
0.12
8
17
0.12
0.14
0.15
0.12
10
17
0.12
0.16
0.16
0.12
12
17
0.12
0.18
0.18
0.12
14
17
0.13
0.20
0.20
0.12
16
17
0.15
0.22
0.23
0.12
18
17
0.16
0.24
0.25
0. 12 0
2
41
4ft by4ft by5h.
0.35
0.30
2
34
0.18
0.30
0.28
0.12
3
24
0.12
0.18
0.18
0.12
4
21
0.12
0.14
0.15
0.12
5
20
0.12
0.14
0.14
0.12
6
19
0.12
0.14
0.15
0.12
8
18
0.12
0.15
0.16
0.12
10
/8
0.12
0.17
0.18
0.12
12
18
0.12
0.19
0.19
0.12
14
18
0.12
0.21
0.21
0.12
16
18
0.13
0.23
029
0.12
in
17
n u
0.26
0.26
0.12
18 19 0.24 0.29 029 0.1
5ftby by6h.
2
28
0.23
0.32
0.27
0.14
3
23
0.15
020
0.21
0.14
4
22
0.14
0.16
0.17
0.14
5
21
0.14
0.16
0.17
0.14
6
21
0.14
•0.17
0.17
0.14
8
20
0.14
0.18
0.19
0.14
10
20
0.14
0.20
0.21
0.14
12
20
0.15
0.23
0.23
0.14
14
20
0.16
0.25
0.26
0.14
16
19
0.18
0.28
0.29
0.14
18
19
0.20
0.31
0.32
0.14
5ftby5ftby6h.c
2
41
0.20
0.35
0.30
0.14
3
29
0.14
0.22
0.23
0.14
4
25
0.14
0.18
0.19
0.14
5
24
0.14
0.17
0.18
0.14
6
22
0.14
0.18
0.19
0.14
8
22
0.14
0.19
0.20
0.14
10
21
0.14
0.21
0.22
0.14
12
21
0.14
0.24
025
0.14
14
21
0.14
0.26
0.27
0.14
16
21
0.16
0.29
0.31
0.14
18
20
0.18
0.32
0.33
0.14
8ftby3ftby7h.
2
29
0.31
0.29
0.27
0.17
3
24
0.21
0.19
0.18
0.17
4
24
0.18
0.17
0.17
0.17
5
24
0.17
0.17
0.17
0.17
6
23
0.18
0.17
0.17
0.17
8
23
0.19
0.19
0.19
0.17
10
23
0.21
0.21
0.21
0.17
12
23
0.23
0.23
0.24
0.17
14
23
0.26
0.26
0.26
0.17
16
23
0.29
0.29
0.30
0.17
18
23
0.32
0.32
0. 33
0.170
Q C 789
TABLE 2 Continued
Design Earth
CO,W. ftA
M. min. In.
Ckt nferentW Ralnfacament Areas•
A A, A., A,
-
Design Earth
cover, ft A
M. min. in.
CImmnferential Relnf Areas
A., Ai, Ass A..
8ttby4ftby7in
7ft by6ftby81n.
2
28
0.27
0.33
0.31
0.17
2
38
0.28
0.39
0.40
0.19
3
25
0.18
0.22
0.21
0.17
3
31
0.19
0.27
028
0.19
4
24
0.17
0.19
0.19
0.17
4
29
0.19
0.24
025
0.19
5
23
0.17
0.18
0.19
0.17
5
28
0.19
024
0.25
0.19
6
23
0.17
0.19
0.20
0.17
6
27
0.19
024
026
0.19
8
23
0.17
0.21
0.22
0.17
8
26
0.19
027
028
0.19
10
22
0.18
023
0.24
0.17
10
26
0.19
0.30
0.31
0.19
12
22
020
026
0.27
0.17
12
26
0.21
0.33
0.34
0.19
14
22
0.22
029
0.30
0.17
14
25
022
0.36
0.38
0.19
16
22
0.25
0.32
0.33
0.17
16
25
0.25
0.41
0.42
0.19
18
22
027
0.36
0.37
0. 170
7 tt by 7 t by 8 imc
8 ft by 5 ft by 7 n.c
- -
2
55
026
0.42
0.43
0.19
2
33
025
0.36
0.34
0.17
3
38
0.19
0.29
0.30
0.19
3
27
0.17
0.24
023
0.17
4
33
0.19
0.25
027
0.19°
4
25
0.17
020
021
0.17
5
31
0.19
0.25
027
0.19
5
24
0.17
0.20
021
0.17
6
30
0.19
0.26
028
0.19
6
24
0.17
021
022
0.17
8
28
0.19
028
0.30
0.19
8
23
0.17
022
0.23
0.17
10
27
0.19
0.31
0.33
0.19
10
23
0.17
025
026
0.17
12
27
0.19
0.34
0.36
0.19
12
23
0.18
028
029
0.17
14
27
0.21
0.37
0.40
0.19
14
23
0.19
0.31
0.32
0.17
16
27
023
0.42
0.
0.19
16
18
22
22
022
0.2
0.34
0.38
0.36
0 .39
0.17°
0.170
8 ft by 4 h by 8 in. c
6 h by 6 h by 7 In.c
2
34
0.43
0.40
0.38
0.19
3
31
0.31
0.28
0.29
0.19
2
48
023
0.39
0.37
0.170
4
28
027
0.25
026
0.19
3
33
0.17
0.26
0.26
0.170
5
28
027
0.25
0.26
0.19
4
29
0.17
0.22
0.23
0.17
6
28
0.27
0.26
027
0.19
5
27
0.17
021
0.23
0.17
8
27
0.30
029
0.30
0.19
6
26
0.17
022
0.23
0.170
10
27
0.33
0.33
0.34
0.19
8
25
0.17
0.23
0.25
0.170
12
27
0.36
0.36
0.37
0.19
10
24
0.17
026
0.27
0.17
12
24
0.17
0.29
0.30
0.17
8 tt by 5 ft by
8 In.c
14
24
0.17
0.32
0.33
0.170
2
35
0.38
0.43
0.42
0.19
16
24
020
0.36
0.37
0.170
3
31
029
0.31
0.32
0.19
18
23
021
0.39
0.41
0.170
4
28
0.25
027
026
0.19
7 h by 4 it by
8 In.c
5
28
0.25
028
029
0.19
2
32
0.34
0.34
0.33
0.190
8
a
27
27
0.25
0.27
029
0.32
0.30
0.33
0.19
0.19
3
4
27
27
023
0.20
023
0.20
0.23
0.21
0.190
0.190
10
27
0.30
0.35
0.37
0.19
0.19
5
26
020
0.20
0.21
0.191D
12
27
0.33
0.40
0.41
6
26
0.20
0.21
0.22
0.19
8 ft by 6 tt by
8 in.c
8
10
26
25
021
023
0.23
026
0.24
027
0.19
0.190
2
36
0.35
0.47
0.46
0.19
12
25
025
0.29
0.30
0.190
3
4
31
30
027
023
0.33
0.29
0.35
0.31
0.19
0.19
14
16
25
25
028
0.32
0.32
0.36
0.33
0.37
0.190
0.190
5
29
023
0.30
0.31
0.19
18
25
0.35
0.40
0.41
0.19
6
8
26
27
023
0.25
0.31
0.34
0.32
0.35
0.19
0.19
7 ft by 5 tt by
8 in.c
10
27
0.27
0.38
0.39
0.19
2
34
0.31
0.37
0.37
0.19
12
27
0.30
0.42
0.44
0.19
3
28
021
026
0.26
0.190
8 tt by 7 tt by
8 In.c
4
5
27
26
0.19
0.19
0.22
022
0.23
0.23
0.19
0.19
2
41
0.33
0.50
0.49
0.19
6
26
0.19
0.23
024
0.19
3
35
0.25
0.35
0.38
0.19
0.19
8
26
0.19
025
0.26
0.19
4
32
022
0.31
0.33
0.19
10
12
25
25
021
023
028
0.31
0.29
0.32
0.19
0.19
5
6
31
30
022
0.22
0.31
0.32
0.34
0.35
0.19
14
25
025
0.35
0.36
0.19
8
29
0.23
0.35
0.38
0.19
0.19
18
25
0.28
0.39
0.40
0.19
10
28
0.25
0.39
0.42
0.190
18
25
0.31
0.43
0.44
0.19
12
28
0.28
0.44
0.46
go C 789
2
38
0.43
0.45
TABLE 2
Continued
3
34
0.33
0.33
Design Earth
M. min. in.
Cir wnferentlal Reinforcement Areas•
Design Earth
M. min, in.
Ucurnferential Reinforcement Arelsa
Cover. ft"
0.22
A„ A
A,
A..
Cover. ft"
0.31
An A,
A,
Aa
0.30
0.31
8It by8ftby8Inc
0.22
8
30
0.32
10 ftby5ftby10 h.
0.35
0.22
2
61
0.31 0.53
0.52
0.19
2
41
0.47 0.46
0.40
0.24
3
41
0.24 0.37
0.40
0.19
3
38
0.36 0.34
0.33
0.24
4
36
0.21 0.33
0.35
0.19
4
35
0.34 0.31
0.32
0.24
5
34
0.20 0.33
0.36
0.19
5
34
0.34 0.32
0.33
0.24
6
32
0.21 0.34
0.37
0.19
6
33
0.34 0.33
0.34
0.24
8
31
0.22 0.37
0.40
0.19
8
33
0.37 0.36
0.37
0.24
10
30
0.24 0.41
0.43
0.19
10
33
0.41 0.40
0.42
0.24
12
29
0.26 0.45
0.48
0.19
12
33
0.45 0.45
0.46
0.24
0.29
0.38
9ftby5ft by9in.c
0.22
4
33
026
10ftby6ft by10ln.
0.36
0.22
2
38
0.43
0.45
0.41
0.22
3
34
0.33
0.33
0.33
0.22
4
31
029
0.29
0.30
0.22
5
31
0.29
0.30
0.31
0.22
6
30
0.30
0.31
0.32
0.22
8
30
0.32
0.34
0.35
0.22
10
30
0.35
0.38
0.39
0.22
12
30
0.39
0.42
0.44
0.22
9ftby6It by9in.
2
2
38
0.40
0.48
0.45
0.22
3
34
0.30
0.35
0.36
0.22
4
32
0.27
0.31
0.33
0.22
5
31
0.27
0.32
0.34
0.22
6
30
0.28
0.33
0.35
0.22
8
30
0.29
0.36
0.38
0.22
10
30
0.32
0.40
0.42
0.22
12
29
0.36
0.45
0.47
0.22
10 tt by 10 tt by
9ftby7ftby91n.
2
2
41
0.37
0.52
0.48
0.22
3
36
0.29
0.38
0.39
0.22
4
33
026
0.33
0.36
0.22
5
32
026
0.34
0.36
0.22
6
31
0.26
0.35
0.37
0.22
8
31
0.28
0.36
0.41
0.22
10
30
0.30
0.42
0.45
0.22
12
30
0.33
0.47
0.50
0.22
9hby8ttby9In.c
2
46
0.35
0.54
0.51
0.22
3
39
0.27
0.40
0.42
0.22
4
36
0.24
0.35
0.38
0.22
5
34
0.24
0.36
0.38
0.22
8
33
025
0.37
0.39
0.22
8
32
0.26
0.40
0.43
0.22
10
31
0.28
0.44
0.47
0.22
12
31
0.31
0.49
0.52
0.22
9 tt by 9 tt by 9 in.
2
68
0.33
0.57
0.55
0.22
3
45
0.26
0.42
0.44
0.22
4
41
0.23
0.37
0.40
0.22
5
38
0.23
0.37
0.40
0.22
6
36
0.23
0.38
0.42
0.22
8
34
0.25
0.41
0.45
0.22
10
33
0.27
0.45
0.49
0.22
12
33
0.30
0.50
0.54
0.22
2
41
0.44
0.49
0.44
0.24
3
37
0.34
0.37
0.36
0.24
4 -- _
- ---34 -__
0.31
0.33
0.35
0.24
5
33
0.31
0.34
0.36
0.24
6
33
0.32
0.35
0.37
0.24
8
33
0.34
0.39
0.41
024
10
32 '
0.38
0.43
0.45
0.24
12
32
0.41
0.48
0.50
0.24
10 It by7it by10in.
2
42
0.41 0.53
0.47
0.24
3
38
0.32 0.39
0.39
0.24
4
35
0.30 0.36
0.38
0.24
5
34
0.30 0.36
0.38
0.24
6
34
0.30 0.37
0.40
0.24
8
33
0.32 0.41
0.43
0.24
10
33
0.35 0.46
0.46
0.24
12
32
0.39 0.51
0.53
0.24
0.51
0.24
10ft by8ftby101n.
33
0.36
2
45
0.38
0.56
0.51
0.24
3
40
0.30
0.41
0.42
0.24
4
37
028
0.38
0.40
0.24
5
36
028
0.38
0.41
0.24
6
35
029
0.39
0.42
0.24
8
34
0.31
0.43
0.46
024
10
33
0.33
0.48
0.51
0.24
12
33
0.36
0.53
0.56
0.24
10 It by9ttby10ln.
2
51
0.36
0.59
0.54
0.24
3
42
029
0.44
0.45
0.24
4
40
027
0.39
0.43
0.24
5
38
0.27
0.40
0.43
0.24
6
37
027
0.41
0.44
0.24
8
35
029
0.45
0.48
0.24
10
35
0.32
0.49
0.53
0.24
12
34
0.35
0.54
0.58
0.24
10 tt by 10 tt by
10 In.O
2
75
0.35
0.61
0.57
0.24
3
50
0.28
0.46
0.47
0.24
4
45
0.26
0.41
0.45
0.24
5
42
0.26
0.41
0.46
0.24
8
40
0.26
0.43
0.47
0.24
8
38
0.28
0.46
0.50
0.24
10
37
0.30
0.51
0.55
0.24
12
36
0.33
0.56
0.60
0.240
qb C 789
TABLE 2 Continued
Design Earth
M, min, In.
Ckamfemtial Reinforcement Arease
Design Earth
M. min, In.
Ckcumferentlal Reinforcement Areass
Cover, ftA
A., A,
A,
A,�
Cover, ftA
A A,
A,
A,.
11 ft by 4 it by 11 In.c
12 ft by 4 ft by 12 in.c
2
45
0.54 0.43
0.35
0.26
2
50
0.58 0.44
0.35
0.29
3
43
0.43 0.32
0.30
0.26
3
47
0.46 0.33
0.30
0.29
4
41
0.40 0.29
0.30
0.26
4
45
0.43 0.31
0.30
0.29
5
39
0.41 0.30
0.31
0.26
5
43
0.46 0.32
0.33
0.29
6
38
0.42 0.31
0.32
0.26
6
42
0.47 0.33
0.34
0.29
8
38
0.45 0.34
0.36
0.26
8
41
0.51 0.36
0.37
029
10
37
0.51 0.39
0.40
0.26
10
41
0.57 0.41
0.42
0.29
12
37
0.57 0.44
0.45
0.26
12
41
0.64 0.46
0.47
029
14
37
0.64 0.49
0.50
0.26
14
41
0.72 0.51
0.52
0.29
16
37
0.71 0.54
0.55
0.26
16
41
0.80 0.56
0.58
0.29
11 ftby6ftbyll in.c
12ft by6it by121n.c
2
44
0.46 0.50
0.43
0.26
2
47
0.50 0.51
0.42
029
3
41
0.37 0.38
0.36
0.26
3
44
0.40 0.39
0.36
0.29
4
38
0.35 0.35
0.35
0.26
4
41
0.38 0.36
0.36
0.29
5
36
0.36 0.36
0.37
0.26
5
39
0.40 0.38
0.39
0.29
6
36
0.36 0.37
0.39
0.26
6
39
0.41 0.39
0.41
0.29
8
36
0.39 0.40
0.42
0.26
8
39
0.44 0.43
0.45
0.29
10
35
0.43 0.46
0.47
0.26
10
39
0.49 0.48
0.50
0.29
12
35
0.48 0.51
0.53
026
12
38
0.55 0.54
0.56
0.29
14
35
0.53 0.57
0.59
0.26
14
38
0.61 0.60
0.62
029
11 ft by 8 ft by 11 i n.c
12 It by 8 it by 12 ln.c
2
46
0.41 0.56
0.49
0.26
2
49
0.45 0.58
0.49
0.29
3
41
0.33 0.42
0.41
0.26
3
44
0.36 0.44
0.42
0.29
4
39
0.31 0.39
0.40
0.26
4
41
0.34 0.41
0.41
0.29
5
37
0.32 0.40
0.42
0.26
5
40
0.36 0.42
0.45
0.29
6
37
0.33 0.41
0.44
0.26
6
39
0.37 0.43
0.46
0.29
8
36
0.35 0.45
0.47
0.26
8
39
0.39 0.47
0.50
0.29
10
36
0.38 0.50
0.53
3.26
10
38
0.44 0.53
0.56
"029
12
35
0.42 0.56
0.59
0.26
12
38
0.48 0.60
0.63
0.29
14
35
0.46 0.62
0.65
0.26
14
38
0.66 0.69
0.69
0.29
llftby10It by 111n.c
1 2ftby10 i tby 121n.c
2
56
0.37 0.62
0.55
0.26
2
55
0.41 0.63
0.55
0.29
3
48
0.30 0.46
0.46
0.26
3
48
0.33 0.48
0.47
0.29
4
44
0.29 0.42
0.45
0.26
4
44
0.32 0.44
0.46
0.29
5
42
0.30 0.43
0.47
0.26
5
43
0.34 0.46
0.49
0.29
6
40
0.30 0.44
0.48
0.26
6
42
0.34 0.47
0.51
0.29
8
39
0.32 0.47
0.52
0.26
8
40
0.36 0.51
0.55
0.29
10
38
0.35 0.53
0.57
0.26
10
40
0.40 0.57
0.61
0.29
12
37
0.38 0.59
0.63
0.26
12
39
0.44 0.63
0.68
029
14
37
0.42 0.65
0.70
0.26
14
39
0.48 0.70
0.75
0.2 9 0
11 ft by 11 ft by 11 In.c
12 It by 12 it by 12 In.c
2
82
0.36 0.64
0.58
0.26
2
89
0.38 0.68
0.80
0.29
3
55
029 0.48
0.48
0.26
3
60
0.31 0.51
0.51
0.29
4
49
028 0.43
0.47
0.26
4
53
0.30 0.47
0.50
029
5
46
029 0.44
0.49
0.26
5
50
0.32 0.48
0.54
0.29
6
44
029 0.45
0.50
0.26
6
48
0.32 0.50
0.55
0.29
8
41
0.31 0.49
0.53
0.26
8
45
0.34 0.53
0.59
0.29
10
40
0.34 0.54
0.59
0.26
10
44
0.37 0.59
0.65
0.29
12
39
0.37 0.60
0.65
0.26
12
43
0.41 0.66
0.72
029
14
39
0.41 0.66
0.71
0.26
14
42
0.45 0.72
0.79
0.29
A The design earth cover Indicated b the height of fill above the top of the box section. Design requirements are based on the material and 5W properties, loading data
and typical section as Included In Appendix X1. For alternative or special designs see 7.2.
a Design steal area In square inches per linear foot of box section at those locations which are ku kated on the typical section Inducted In Appendix X1.
c The box section designation. for example, 3 It by 2 ft by 4 in.. Indicates (Interior Horizontal Span, In feet) by (Interior Vertical Rise, in feet) by (Wall and Slab ThIclasm.
In inches).
0 Minimum practical 31601 area 13 spedfled.
40 C 789
TABLE 3 Design Requirements for Precast Concrete Box Sectlons4nder Earth Dead Load CondidonsA
NOTE 1- )esign earth covers and relMarcement areas am be an the weight of a colurm of earth over the width of the box section as dented in Appardx X1. See
Appendix X2 for modi8catlons to relnfacenient areas for other earth load conditions.
Nore 2- Concrete Design Strength 5000 psi.
Design Earth
M. min, In.
Clranferentlal Reinforcement Areas'
Design Earth
M, min, in.
CkaxnferentW Reinforcement
Areas° --
Cover, tt
0.10
A., A
A
AM
Cover, ft
0.12
Apt A
A,
A.,
0.10 0.13
0.13
3 it by 2 It by 4 ln.o
16
14•
0.10 0.15 •
0.15
6 It by 5 it by 6 ln.c
18
14
0 to 10
14
0.10 0.10
0.10
0.10
0 to 8
22
0.14 0.14
0.14
0.14
12
14
0.10 0.10
0.11
0.10
10
21
0.14 0.16
0.17
0.14
14
14
0.10 0.12
0.12
0.10
12
20
0.14 0.19
0.20
0.14
16
14
0.10 0.14
0.14
0.10
14
20
0.14 0.22
0.23
0.14
18
14
0.11 0.16
0.16
0.10
16
20
0.14 0.25
026
0.14
20
14
0.13 0.17
0.18
0.10
18
20
0.15 0.28
0.30
0.14
22
14
0.14 0.19
0.19
0.10
20
20
0.17 0.32
0.33
0.14
3nby3ftby4in.c
0 to 10
15
0.10 0.10
0.10
0.10
12
14
0.10 0.11
0.12
0.10
14
14
0.10 0.13
0.13
0.10
16
14•
0.10 0.15 •
0.15
0.10
18
14
0.10 0.17
0.17
0.10
20
14
0.10 0.19
0.19
0.10
4Itby2itby5lnc
0 to 10
18
0.12 0.12
0.12
0.12
12
17
0.12 0.13
0.13
0.12
14
17
0.14 0.15
0.15
0.12
16
17
0.16 0.17
0.17
0.12
18
17
0.18 0.19
0.19
0.12
20
17
021 021
021
0.12
20
22
4 it by 31t by 5 ln.c
0.36
0.17
0 to 8
17
0.12 0.12
0.12
0.12
10
17
0.12 0.12
0.13
0.12
12
17
0.12 0.14
0.15
0.12
14
17
0.12 0.17
0.17
0.12
16
17
0.12 0.19
020
0.12
18
17
0.14 0.22
0.22
0.12
20
17
0.16 0.24
025
0.12
20
21
4ftby4itby5ln.c
0.39
0.17
0 to 8
18
0.12 0.12
0.12
0.12
10
17
0.12 0.13
0.13
0.12
12
17
0.12 0.15
0.16
0.12
14
17
0.12 0.18
0.18
0.12
16
17
0.12 0.20
021
0.12
18
17
0.12 0.23
023
0.12
20
17
0.13 0.25
026
0.12
18
23
5 it by3Itby6in.
0.36
0.17
0 to 8
20
0.14 0.14
0.14
0.14
10
19
0.14 0.14
0.15
0.14
12
19
0.14 0.17
0.18
0.14
14
19
0.16 0.20
0.20
0.14
16
19
0.18 0.23
0.23
0.14
18
19
0.21 0.25
0.26
0.14
20
19
0.23 028
0.29
0.14
20
25
5ftby by6 in.c
0.40
0.19
0108
20
0.14 0.14
0.14
0.14
10
19
0.14 0.16
0.16
0.14
12
19
0.14 0.17
0.19
0.14
14
19
0.14 0.22
0.22
0.14
16
19
0.15 0.25
0.25
0.14
18
19
0.17 0.28
0.28
0.14
20
19
0.19 0.31
0.31
0.14
6ftb
0 to 10
23
0.17 0.17
0.17
0.17
12
23
0.18 0.19
020
0.17
14
23
0.21 0.23 '
023
0.17
16
23
024 026
026
0.17
18
23
0.28 029
0.29
0.17
20
23
0.31 0.32
0.33
0.17
6ftby4itby71n.c
0 to 8
23
0.17 0.17
0.17
0.17
10
22
0.17 0.18
0.19
0.17
12
22
0.17 021
022
0.17
14
22
0.18 0.25
026
0.17
16
22
021 028
029
0.17
18
22
023 0.32
0.33
0.17
20
22
026 0.35
0.36
0.17
6 it by 5 it by 7 In.c
0 to 8
23
0.17 0.17
0.17
0.17
10
21
0.17 0.19
020
0.17
12
21
0.17 023
024
0.17
14
21
0.17 026
027
0.17
16
21
0.18 0.30
0.31
0.17
18
21
0.20 0.34
0.35
0.17
20
21
023 0.37
0.39
0.17
6ttby0ftby7In.
0 to 6
26
0.17 0.17
0.17
0.17
8
24
0.17 0.17
0.18
0.17
10
24
0.17 020
0.21
0.17
12
24
0.17 0.23
025
0.17
14
23
0.17 027
0.29
0.17
16
23
0.17 0.31
0.32
0.17
18
23
0.18 0.34
0.36
0.17
7 it by 4 it by 8 In.c
0 to 8
26
0.19 0.19
0.19
0.19
10
25
0.19 0.20
021
0.19
12
25
0.20 0.24
025
0.19
14
25
023 0.28
0.29
0.19
16
25
027 0.32
0.33
0.19
18
25
0.30 0.36
0.36
0.19
20
25
0.34 0.40
0.40
0.19
7 it by 5 it by 8 in.c
0 to 6
26
0.19 0.19
0.19
0.19
10
25
0.19 0.22
0.23
0.19
12
25
0.19 0.26
027
0.19
14
25
0.21 0.30
0.31
0.19
16
25
0.23 0.34
0.35
0.19
18
25
0.26 0.38
0.39
0.190
qUO C 789
TABLE 3 Continued
Design Earth
Cover. h A
M, min, In.
Quenterentiai Reinforce A
A., A, A Ai4
Design Earth
Cover, n A
M, min. In.
Cirunferentlal Renforcerent Areas°
A., A, A A i4
28
0.19 0.19
7 ft by 6 it by 8 ln.c
0.19
6
27
0.19 0.19°
9 ft by 6 tt by 9 in.c
0.19
8
0 to 6
27
0.19 0.19
0.19°
0.19
0 to 6
31
0.22 0.22
0.22
0.22
8
26
0.19 0.19
0.20
0.19
8
29
0.22 0.26
0.28
0.22
10
25
0.19 0.23
0.24
0.19
10
29
0.24 0.32
0.33
0.22
12
25
0.19 027
0.29
0.19
12
29
0.28 0.38
0.39
0.22
14
25
0.19 0.31
0.33
0.19
14
29
0.33 0.43
0.45
0.22
16
25
021 0.35
0.37
0.190
14
8itby8ftby81n.c
0.36
0.41
0.42
18
25
0.24 0.40
0.41
0.19°
33
024 0.24
9 ft by 7 ft by 9 in. c
0.24
8
32
0.24 0.30
7 It by 7 ft by 8 in.
0.24
10
0 to 5
32
0.22 0.22
0.22
0.22
32
0.31 0.42
0.45
024
14
6
30
0.22 0.22
0.24
0.22
0 to 6
30
0.19 0.19
0.19
0.190
8
30
0.22 0.27
0.29
022
8
27
0.19 0.19
0.21
0.199)
10
30
0.23 0.33
0.35
0.22
10
27
0.19° 024
0.25
0.190
12
29
027 0.39
0.41
0.22
12
27
0.19 028
0.30
0.190
14
29
0.31 0.45
0.48
0.22
14
26
0.19 0.32
0.34
0.19
16
26
020 0.36
0.38
0.19
9 1t by 6 it by 9 In.
18
26
022 . 0.41
0.43
0.19°
0 to 5
34
022 0.22
022
0.22°
8 it by 4 It by 8 in.c
6
32
0.22 022
025
0.22
0 to 6
28
0.19 0.19
0.19
0.190
8
31
0.22 0.28
0.31
022
8
27
020 021
0.22
0.190
10
31
0 22° 0.34
0.37
0.22°
10
27
024 0.26
0.27
0.190
12
30
025 0.40
0.43
022°
12
27
029 0.30
.0.31.
0.19
14
30
029 0.47
0.50
022°
14
27
0.34 0.35
0.36
0.19
9 it by 9 it by 9 in.c
8 it by 5 it by 8 in.c
0 to 4
38
022 0.22
0.22
0.22
0 to 6
28
0.19 0.19
0.19
0.190
5
35
0.22 022
0.23
022°
8
27
0.19 0.23
0.24
0.190
6
34
0.22 0.23
0.26
0.22
10
26
0.22 028
0.29
0.190
8
33
0.22 0.29
0.32
0.22
12
26
0.26 0.33
0.34
0.190
10
33
0.22 0.35
0.39
0.22
14
26
0.30 0.38
0.39
0.19
12
32
0.24 0.41
0.45
0.22
14
32
027 048
051
022°
0 to 4
34
a ft by6ftby8h.c
0.19
0.19
0 to 5
28
0.19 0.19
0.19
0.19
6
27
0.19 0.19°
0.20
0.19
8
27
0.19 0.24
0.26
0.19
10
27
020 0.29
0.31
0.19
12
27
0.24 0.35
0.36
0.19
14
27
028 0.40
0.42
0.19
0.19
14
8 it by 7 ft by 8 in.c
0.24
0.
0 to 5
30
0.19 0.19
0.19
0.19
6
28
0.19 0.20
0.22
0.19
8
27
0.19 0.25
0.27
0.19
10
27
0.19 0.30
0.33
0.19
12
27
0.22 0.36
0.38
0.19
14
27
0.26 0.42
0.44
0.19
0.22
14
8itby8ftby81n.c
0.36
0.41
0 to 4
34
0.19
0.19
0.19
0.19
5
31
0.19
0.19
020
0.19
6
30
0.19
0.20
0.23
0.19
8
30
0.19
026
0.28
0.19
10
29
0.19
0.31
0.34
0.19
12
29
0.21
0.37
0.40
0.19
14
29
0.24
0.
0.45
0.19°
10it by6It by101n.°
9ttby5itby9in
0 to 6
34
0 to 6
31
0.22
0.22
0.22
0.22
8
30
0.22
0.24
0.26
0.22
10
29
0.26
0.30
0.31
0.22
12
29
0.31
0.35
0.37
0.22
14
29
0.36
0.41
0.42
0.22°
10 it by8ttby10in.c
0 to 5
10 ft by 5 ft by 10 ln.c
0.24
0.24
0 to 6
34
0.24 0.24
0.24
0.24
8
33
0.25 0.26
0.27
0.24
10
33
0.31 0.32
0.33
0.24
12
33
0.36 0.38
0.39
0.24°
14
32
0.42 0.44
0.45
0.24
16
32
0.48 0.44
0.51
0.24
0.54
0.240
10it by6It by101n.°
0 to 6
34
0.24 0.24
0.24
0.24
8
32
024 0.28
0.30
0.24
10
32
028 0.34
0.36
0.24
12
32
0.33 0.40
0.42
0.24
14
32
0.39 0.46
0.48
0.24
10 It by 7 it by 10 in.c
0 to 5
34
0.24 0.24
0.24
024°
6
33
024 0.24
0.25
0.24
8
32
0.24 0.30
0.32
0.24
10
32
026 0.36
0.38
0.24
12
32
0.31 0.42
0.45
024
14
32
0.36 0.49
0.51
024
10 it by8ttby10in.c
0 to 5
36
0.24
0.24
0.24
0.24
6
34
0.24
0.24
0.27
0.24
8
33
024
0.31
0.33
0.24
10
33
0.25
0.37
0.40
0.24
12
32
0.29
0.44
0.47
0.24
14
32
0.34
0.51
0.54
0.240
4D C 789
TABLE 3
Co
Design Earth
M. min. In.
Ck=forentlel Rohfort wwt Areasa
Design Earth
M, min, In.
Ckcumforentlal Reinforcement Arsesa
./ Cover. ftA
A.,
A iz
A
A.,
Cover, ftA
A.,
A.,
A,
A w
10ftby9ftby101n.
11it by10ftby11h.
0 to 4
38
0.24
0.24
0.24
0.24
0 to 2
42
0.26
0.26
0.26
026
5
36
024
024
025
024
3
41
0.26
026
026
026
8
35
024
0.25
0.29
0.24
4
40
026
026
026
0.26
8
34
024
0.32
0.35
0.24
5
39
026
0.26
0.27
0.26
10
34
024
0.38
0.42
0.24
6
39
026
027
0.30
026
12
33
028
0.45
0.49
0.24
8
38
0.26
0.33
0.37
026
14
33
0.32
0.52
0.56
0.24
10
37
026
0.40
0.44
026°
12
37
0.30
0.47
0.52
026
10 It by 10 ft by 10 in.c
14
36
0.35
0.55
0.59
026
16
36
0.39
0.62
0.66
026
0 to 4
43
024
024
024
024
11 ft by 11 It by 11 h.c
5
38
024
024 _
027
0240
0 to 2
47 -
-- - 026°
026
026
026
6
37
024 9)
0.26
030
0.240
3
44
026
_
026
026
026
8
36
024
0.33
0.37
0240
4
43
026
026
026
026
10
36
024
0.39
0.44
0:240
5
42
026
0.26
028
028
12
35
027
0.46
0.50
024
6
41
026
0.27
0.32
0.26
14
35
0.31
0.53
0.57
024
8
40
026
0.34
0.39
026
10
39
026
0.41
0.46
026
11 It by 4 ft by
11 h.c
12
39
029
0.48
0.53
0.26
14
38
0.34
0.55
0.60
026
0 to 2
38
026
026°
026
026
16
38
0.38
0.62
0.68
026
3
38
0.26
0260 0 260
h
0.260
12 by 4 ft by 12 h.c
4
38
028
026
0.26
028
5
38
026
026
026
026
0 to 2
42
029
029
029
029
6
37
026
026
026
026
3
42
0.29
029
0.29
029
8
37
0.31
026
0.26
026
4
41
029
0.29
029
029
10
37
0.37
0.31
0.32
026
5
41
0.29
0.29
0.29
0.29
12
37
0.45
0.36
0.37
0.26
6
41
029
029
029
0.29
14
37
0.52
0.42
0.43
026
8
41
0.35
0.29
0.29
029
16
37
0.60
0.47
0.48
026
10
41
0.43
0.32
0.33
0.29
18
37
0.68
0.53
0.54
026
12
41
0.51
0.38
0.39
0.29
14
41
0.59
0.44
0.45
029
11 ft by 6 ft by
11 In.c
16
41
0.68
0.50
0.51
029
18
41
0.77
0.56
0.57
0.29
0 to 2
36
026
028
026
0.26
12 It by 6 ft by
12 h.c
3
36
026
0.28
026
0.28°
0 to 2
40
029
029
029
029
4
36
026
026
0.26
0.260
3
39
029
0.29
029
0.29
5
36
026
026
0.26
0.260
4
39
029
029
029
0.29
6
35
026
026
0.26
0260
5
39
029
029
029
029
8
35
027
0.29
0.31
0.260
6
39
0.29
029
0.29
029
10
35
0.32
0.36
0.3)
0.26
6
38
0.30
0.31
0.33
029
12
35
0.38
0.42
0.44
0260
10
38
0.37
0.38
0.39
029
14
35
0.44
0.48
0.50
0280
12
38
0.43
0.44
0.46
029
16
35
0.50
0.55
0.57
0260
14
38
0.50
0.51
0.53
029
18
35
0.56
0.62
0.64
0.260
16
38
0.57
0.58
0.60
0.29
18
38
0.64
0.65
0.67
0.29
11It by8ttby11
h.c
12ft byeftbyl2h. c
0 to 2
38
026
026
0.26
026
0 to 2
40
029
029
0.29
029
3
37
026
026
026
026
3
39
029
0.29
029
029
4
38
026
026
026
026
4
39
029
029
029
029
5
36
0.26
026
028
0.26
5
39
029
029
0.29
029
6
36
026
026
028
028
6
38
0.29
029
0.30
029
8
35
026
0.32
0.34
026
8
38
029
0.34
0.37
029
10
35
028
0.39
0.41
028
10
38
0.32
0.41
0.44
0.29
12
35
0.33
0.46
0.48
0.26°
12
37
0.38
0.49
0.52
029
14
35
0.38
0.53
0.55
026
14
37
0.43
0.56
0.59
029
18
35
0.43
0.60
0.85
0.26
16
37
0.49
0.64
0.87
0290
OffO C 789
TA 3 Continued
Design Earth
M, mkt, In.
Circumferential Reinforcement Areas'
Design Earth
M, min, In.
Cin mferentlal Rainforcernent A
Cover, ftA
A.,
A.
A,
A,4
Cover, ftA
A.,
A.2
A,
A.
12ttby10nby12ln.c
12nby12ttby12kt.c
0 to 2
43
0.29
0.29
0.29
0.29
0 to 2
52
0.29
0.29
0.29
0.29
3
42
0.29
0.29
0.29
0.29
3
49
0.29
0.29
0.29
0.29
4
41
029
0.29
0.29
0.29
4
46
0.29
0.29
0.29
0.29
5
41
0.29
0.29
0.29
0.29
5
45
0.29
0.29
0.32
029
6
40
0.29
0.29
0.33
0.29
6
45
0.29
0.30
0.35
0.29
8
39
0.29
0.36
0.40
0.29
8
43
0.29
0.38
0.43
0.29
10
39
0.30
0.44
0.48
0.29
10
43
0.29
0.45
0.50
0.29
12
39
0.34
0.51
0.55
0.29
12
42
0.33
0.53
0.58
0.29
14
38
0.39
0.59
0.63
0.29
14
41
0.37
0.60
0.66
0.29
16
38
0.
0.6
0.71
0.29
16
41
0.42
0.68
0. 75
0.29
A The design earth cover indicated is the freight of fill above the top of tine box section. Design requirements are be On the material and soil properties. loading data
and typical section as included In Appendix X1. For alternative or spacial designs see 7.2.
a Design steel area in square inches per linear foot of box section at those locations which are Indicated on the typical section include! in Appendix X1 -
0 The box section designation, for example. 3 ft by 2 ft by 4 n.. indicates (interior Horizontal Span in feet) by (Interior vertical Rise in feet) by (Wad and Slab Thickness
in inches).
0 Mnkntxn practical steel area is specified.
APPENDIXES
(Nonmandatory Information)
XI. DESIGN CRITERIA USED TO DEVELOP TABLES 1, 2,, AND 3
X1.1 Bedding and Backfill Assumptions
X 1.1.1 The bedding is assumed to provide a slightly
yielding, uniformly distributed support over the bottom
width of the box section.
X1.1.2 The design earth covers and reinforcement areas
are based on the weight of a column of earth over the width
of the box section.
X1.1.3 Refer to Appendix X2 for other bedding and
backfill conditions.
X1.2 Criteria for Loads
X 1.2.1 Design loads are based on the American Associa-
tion of State Highway and Transportation Officials
( AASHTO) "Standard Specifications for Highway Bridges,"
Twelfth edition, 1973.
X1.2.2 Live loads for designs given in Table l are H2O
truck wheel loads as defined in the AASHTO specifications.
Live loads for designs given in Table 2 are either the H2O
truck wheel loads, or interstate truck wheel loads as defined
in U.S. Dept. of Commerce, Bureau of Public Roads
Circular Memorandum 2240, 22 April 1957, depending
upon whichever produces the more severe design strength
requirements (see Fig. X I A ). Distribution of truck wheel
loads through earth fills is in accordance with Section 1.3.3
in the AASHTO specifications. Earth cover loads for designs
given in Tables 1, 2, and 3 are the weight of a column of
earth of a width equal to the outside width dimension of the
box section and a height equal to the depth of earth cover
over the top of the section. This earth load is recommended
in Section 1.2.2 (A) of the AASHTO Bridge Specifications
for the normal case of box culverts on "yielding" subgrade.
The AASHTO specifications define an "unyielding"
subgrade as "rock or piles" and require the use of the Iowa
formulas for this case. See Appendix X2 for a method to
modify the designs given in Tables 1, 2, and 3 when the
anticipated earth load, or earth load plus uniformly distrib
uted surface surcharge load, is greater (or less) than th,,_,/
weight of the column of earth directly above the out -to -out
width of the box sections.
X 1.2.3 Section 1.2.2 of the AASHTO specification allows
the design of buried structures, such as box section culverts,
for 70 % of the weight of earth directly above the out- to-out
width of structure. On the other hand, the Manton - Spangler
theory of earth loads on buried pipe gives a total earth load
greater than the weight of the column of earth directly over
the structure for most "positive projecting" culverts, and less
than the weight of the column of earth over the structure for
"trench type" installations, "negative projecting" culverts,
and "induced trench" culverts. In view of the number of
different installation conditions which may be encountered
and the use of higher reinforcing steel stresses associated with
the ultimate strength design method (see X1.2), the 30 %
reduction in weight of supported earth load permitted in
Section 1.2.2 of the AASHTO specification is not utilized for
the tabulated designs, and a method of modifying designs for
anticipated earth loads which differ from the above described
"standard earth load" is given in Appendix X2.
X1.2.4 Lateral earth pressure from weight of earth above
and adjacent to a box section is taken as a minimum of 0.25
times vertical pressure, and an additional 0.25 times vertical
pressure is added when determining steel areas only when
areas are increased by such increased lateral pressure. For
Tables 1 and 2, additional lateral pressure in lbf /ft fror
approaching truck wheel loads is taken as 700 divided by
depth of earth cover in feet and is added when determining
steel areas only at sections where area is increased by
increased lateral pressure.
90 c 789
TABLE X2.1 Design Information for Revising Tabulatecl R einforcing Steel Areas
cuNerc size
Cftmp In Reinforcing Steel Area
per 1000 Ibt/ft Change In Total
Weight on Box Section
�
m
Maximum W.
lof/ftA
culvert size
Change In Reinforckp Steel Area
per 1000 Ibflft change In Total
Weight on Box Section
.
m AA.,,
In . m
bl W.
3 ft by 2 it by 4 in.
0.018
0.023
9 500
9 it by 5 it by 9 in.
0.022
0.025
20 300
3 ft by 3 it by 4 In.
0.013
0.028
9 400
9 it by 6 it by 9 in.
0.020
0.027
20100
4 it by 2 it by 5 in.
0.021
0.020
12 200
9 it by 7 ft by 9 In.
0.018
0.029
19 800
4 ft by 3 it by 5 in.
0.016
0.025
12100
9 it by 8 ft by 9 in.
0.016
0.030
19 600
4 ft by 4 It by 5 in.
0.013
0.028
12 000
9 it by 9 ft by 9 in.
0.015
0.031
19 400
5 ft by 3 ft by 6 In.
0.019
0.022
14 800
10 it by 5 ft by 10 In.
0.022
0.023
22 800
5 It by 4 It by 6 In.
0.015
0.025
14 700
10 It by 6 it by 10 In.
0.020
0.025
22 500
5 ft by 5 ft by 6 In.
0.012
0.028
14 500
10 it by 7 ft by 10 In.
0.019
0.027
22 300
6 ft by 3 it by 7 In.
0.020
0.020
17 500
10 ft by 8 it by 10 in.
0.017
0.028
22100
6 ft by 4 It by 7 in.
0.017
0.023
17 300
10 it by 9 ft by 10 in.
0.015
0.030
21 800
6 ft by 5 it by 7 In.
0.015
0.026
17100
10 it by 10 it by 10 in.
0.014
- 0.031
21 600
6 It by 6 It by 7 in.
0.013
0.028
16 900
11 ft by 4 it by 11 in.
0.024
0.020
25 300
7 it by 4 ft by 8 In.
0.019
0.022
19 800
11 ft by 6 It by 11 in.
0.021
0.023
24 900
7 it by 5 It by 8 in.
0.016
0.024
19 600
11 ft by 8 it by J1 in.
0.018
0.026
24 500
7 It by 6 it by 8 In.
0.014
0.026
19 400
11 it by 10 ft by 11 in.
0.015
0.029
24 000
7 ft by 7 it by 8 in.
0.013
0.028
19 300
11 it by 11 it by 11 In.
0.013
0.030
23 800
8 ft by 4 it by 8 in.
0.024
0.024
18 000
12 it by 4 ft by 12 in.
0.025
0.018
27 800
8 it by 5 it by 8 in.
0.021
0.027
17 SW
12 It by 6 it by 12 in.
0.022
0.021
27 400
8 ft by 6 it by 8 in.
0.018
0.029
17 600
12 it by 8 it by 12 in.
0.019
0.024
27 000
8 ft by 7 It by 8 in.
0.016
0.030
17 400
12 it by 10 ft by 12 in.
0.016
0.027
26 500
8 It by 8 it by 8 In.
0.015
0.032
17 200
12 It by 12 ft by 12 in.
0.013
0.030
26 200
" Maximurn allowable total weight on box section as governed by shear strength of box section without stirrups.
X2.3.2 Find -The required A,,, A and A circumfer-
ential reinforcement areas. In all uses A, is governed by the
minimum steel areas as described in X1.4.2 and is not
changed by increased vertical loads.
X2.3.3 Solution:
X2.3.3.1 Effective unit weight of soil = 110 x 1.36 = 150
lbf /ft
X2.3.3.2 Determine change in total weight of earth on
culvert in kips force /linear ft (1000 lbf /ft):
W -HxBxw
where:
W = total weight of earth on culvert, kf /ft,
H = height of earth cover, ft,
B = outside span, ft,
W = unit weight of earth, kf /ft
W 120 = 14 x 7.167 x 0.120 = 12.040 kf /ft,
W, so = 14 x 7.167 x 0.150 - 15.051 kf /ft, and
W = WI30 - W120 = 3.011 kf /ft.
X2.3.3.3 Determine the change in circumferential rein-
forcement areas. From Table 1, for a 6 ft by 6 ft by 7 in.
section under 14 ft of covers A,, = 0. 17, A = 0.32, and A
= 0.33 in. /11. From Table X2.1, for a 6 ft by 6 ft by 7 in.
section, the changes in reinforcing areas are, for A,,, 0.013,
and for A, and A 0.02 B. in. /ft for each 1000 lbf /ft of load
change. Therefore:
AA,, =3.011 x0.013=0.039
AA = 3.011 x 0.028 = 0.084
AA, - 3.011 x 0.028 = 0.084
Therefore, the correct reinforcement areas are as follows:
A,, - 0.17 + 0.04 - 0.21 in.z /ft
A - 0.32 + 0.08 - 0.40 in. /ft
A, - 0.33 + 0.08 - 0.41 in. /ft
X2.3.3.4 Determine if the total weight of earth on the
culvert is less than maximum as governed by the shear
strength of culvert without stirrups.
X2.3.3.5 From Table X2.1, the maximum allowable
weight = 16 900 lbf /ft. From X2.3.3.2, W, = 15 051
lbf /ft. The approximate equivalent uniform load from an
HS20 live load at 14-ft burial depth is about 160 ibf /ft or a
total load of 1150 lbf /ft (160 x 7.167). Therefore, the total
weight on the box section is 16 200 Ibf /ft (15 050 + 1 150)
which is less than the maximum allowable; therefore the
design is satisfactory.
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110 C 789
TABLE X1.1 Specific Criteria Used for Tables 1, 2, and 3
Material Propertles:
Welded wire fabric, minknurn specified yield
65 000 psi
stress
Canaste, r>INrnurn specified compressive
5 000 psi
strength
S000. ta
Ratio teral to vertical pressure from weight
0.25 min to 0.50 max
of earth
AdditI0rW lateral pressure from approaching
700 + H. Ibf/ft where H
truck wheels
earth cover, it
External water table
below box section invert
Effective weight coefficient
1.0
Capacity Reduction Factors (from ACf 318 -71)
Shear
0.85
Axial compression combined with bending"
0.70 to 0.90
Loading Data
Load factor —dead load
1.5
Load factor —Yve load
2.2
Truk axle load:
H2O (Table 1)
32 000 Ibf
Interstate (Table 2)
2 @ 24 000 Ibf each
Nor* (Table 3)
Impact (variable with depth) see AASHTO Bridge
0 to 20 x
Specifications, 1977
Worm intemal pressure
0.0
Depth of water In box section
equal to inside height
E ternal ground water pressrxO
0.0
Arr angement.-
Concrete cover over steel
1.0 in.
Slab thickness
+/u times inside span plus
1.0 In. up to 7 - n
span — Inside span
above span
Side wag thk kness
� l
Haunch dimensions
vertkall and horizontal dl-
mansions both equal to
slab thickness
Mkwnum reinforcing Inside face slabs and side
0.002 bt
wags, outside face site walls and corners of
slabs
The structural arrangement and details are
shown In Fig. 1.
"See ACI 318 -71, Section 9.2.1.2(c).
minimum practical steel area. For such designs, the steel
areas calculaied for support of design loads are less than th
minimum steel area which is specified for slabs in AASHT011)
Specification, 0.002 bt, and thus, the minimum reinforce-
ment areas are shown in the tables.
X 1.4.3 For specific criteria used in Tables 1, 2, and 3,
refer to Table X 1.1.
X 1.4.4 The maximum height of earth cover shown in the
tables is determined by the shear strength of the box section
without the use of special shear reinforcement, as given in
Sections 11.2.1, 11.2.2, and 11.4.1 ofACI 318 -71, and by the
"standard weight" of the column of earth directly above the
box section. See Table X2.1 for the maximum loads which
can be carried on the standard box sections. These loads can
be used to determine maximum earth cover heights when the
anticipated weight of earth supported by the section is greater
than (or less than) the above "standard weight" of earth
cover.
XIS Multiple Cell Installations
X1.5.1 The designs given herein are for single cell precast
reinforced concrete box sections. The units may be used in
parallel for multicell installations if means of positive lateral
bearing by continuous contact between the sides of adjacent
boxes are provided. Compacted earth fill, granular backfill,
or grouting between the units are considered means of
providing such positive bearing.
X2. MODIFICATION OF "STANDARD" BOX SECTION DESIGNS FOR EARTH LOADS DIFFERENT FROM
THE "STANDARD" EARTH LOAD
X2.1 The heights of cover given in Tables 1, 2, and 3 are
based on a "standard weight of earth fill" equal to the weight
of a column of earth with a unit weight of 120 lbf /ft' and a
width equal to the out - to-out width of the box section. For
some installations, the design engineer may determine that
for a given height of cover, the weight of earth to be
supported by the box section is more or less than the above
"standard weight of earth fill" used to develop the designs
given in the tables.
X2.1.1 For example, the Marston - Spangler theory for
loads on buried structures indicates that the weight of earth
that must be supported by most "positive projecting" con-
duits is greater than the weight of a column of earth directly
over the conduit, while the weight of earth that must be
supported by "trench -type" conduits, "negative- projecting"
conduits, and "induced - trench" conduits is less than the
weight of earth over the conduits. Also, the designer may
wish to a unit weight of earth more or less than the 120
lbf /ft' used in the "standard weight," or may wish to include
a particular uniformly distributed surface surcharge loading.
X2.2 Incremental reinforcing steel areas are given in
Table X2 for each box section type. Where installation
conditions warrant the use of a weight of earth more or less
than the "standard weight," the designer may utilize these
incremental areas to modify the steel areas given in Tables 1,
2, or 3 for a particular height of cover. The maximum total
weight of earth fill that may be supported over the out - to-out
width of each standard box section size, as governed by shear
strength without shear reinforcing, is also given in Table
X2.1. Thus, for any weight of earth or surface surcharge, or
both, a designer can use Tables 1, 2, 3 and X2.1 to
determine the required area of reinforcing steel for various
heights of earth cover, or the maximum height of earth cover
without special shear reinforcing, for any of the standard box
section sizes shown in these tables.
X2.3 The following design example illustrates how the
above tables may be used to obtain a suitable design for a
box section to support an earth load that is greater than the
"standard weight of earth" used to develop Tables 1, 2, and
3.
Example.
X2.3.1 Given —A 6 ft by 6 ft by 7 in. Table 1 precast con-
crete box section under 14 ft of cover with 110 Ibf /ft' earth
and an effective weight of earth supported by the section of
1.36 times the weight of the column of earth directly over the
section instead of the standard 120 lbf /ft earth.
IV,
4D C 789
WHEEL SPACING
HS -20 Truck
and
6
Interstate Alternate Load
AXLE LOADS
HS -20 Load
1,000 111 )2.00011 32.000 IM
14 �4 mi - 30 1 m axi
AXLE LOADS 0 1 1
24, 000 lbf 24,000 lbf
Interstate Alternate Load I 41---�
FIG. X1.1 Axle Loads for Box Section Standard Designs
X13 Methods of Analysis
X1.3.1 The structural effects of the loads described in
X 1.2 are evaluated based on the elastic method of structural
analysis. Design moments, shears, and thrusts are deter-
mined by computer analysis using the stiffness matrix
method, and design is based on maximum stress resultants at
critical sections caused by the most severe combination of
design loads.
X1.4 Method of Design
X1.4.1 Design heights of earth cover, wall thicknesses,
and reinforcing steel areas are determined based on the
elastic method of structural analysis and the ultimate
strength method of reinforced concrete design given in the
1971 ACI Building Code (ACI 318 -71). Steel areas are
governed by ultimate flexural strength. The steel areas and
the size and spacing of circumferential wires are propor-
tioned to limit the maximum crack width to 0.01 in. under
design load conditions. Evaluation of crack control with the
welded wire fabric reinforcement specified for the tabulated
designs is based on the results of research by Lloyd, Rejali,
and Keslera at the University of Illinois, and is significantly
more conservative than the crack control provisions given in
ACI 318 -71. This is because it is recognized that approxima-
tions which were used to simplify the ACI crack control
provisions can result in unconservative designs for thin
elements such as slabs. Standard designs do not cover
installations that must resist significant external water pres-
sure. Furthermore, installations that are subject to high
external water pressure may require vertical reinforcement
for the inside face of the side walls. Lloyd, Rejali, and Kesler
suggest that crack control equations developed for deformed
bar reinforcement may also be used for both welded smooth
wire fabric and deformed wire fabric reinforcement.
X 1.4.2 Note that some box section designs shown in the
tables have steel area requirements designated by "D" as
Lloyd, J. P., Rcjali. H. M.. and Kesler, C. E. "Crack Control in One -Way
Slabs Reinforced with Deformed Welded Wire Fabric,' Journal of the American
Concrete Institute Proceedings, PACIA, Vol 66, No. 3, May 1969.
n,