Installation Guide eBook

8/2/2019 Installation Guide eBook

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Concrete Pipe

& Box Culvert

Installation

RESOURCE NO 01-103

1303 West Walnut Hill Lane, Suite 305

Irving, Texas 75308-3008Phone: 972.506.7216Fax: 972.506.7682

[email protected]


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American Concrete Pipe Association www.concrete-pipe.org

TableofContents

I.CONCRETE PIPE INSTALLATION MANUAL... 5Introduction................................................... 5

PRE-CONSTRUCTION...................................... 6Precautions................................................... 6Ordering, Receiving And Handling............... 6Unloading...................................................... 7Stockpiling.................................................. 10

INSTALLATION................................................ 12

Line And Grade........................................... 12Excavation Limits........................................ 17Excavated Material..................................... 19Dewatering.................................................. 19Standard Installations................................. 20Class A Bedding......................................... 27

Class B Bedding......................................... 27Class C Bedding......................................... 28Class D Bedding......................................... 29Jointing....................................................... 38

Rubber.................................................... 38Mastic......................................................42

Mortar..................................................... 42Geotextile Filter Fabrics.......................... 43External Bands....................................... 43

Joint Procedures.........................................44Service Connections................................... 46Curved Alignment....................................... 46

Final Backlling........................................... 50Acceptance Tests....................................... 50Soil Density................................................. 51Line And Grade........................................... 52Visual Inspection......................................... 52Inltration.................................................... 53

Exltration................................................... 56Air Testing................................................... 58Vacuum Testing.......................................... 61


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Joint Testing-Air.......................................... 62Joint Testing-Water..................................... 62

II. BOX CULVERT INSTALLATION MANUAL....64

Introduction................................................. 64PRE-INSTALLATION...................................... 65

Precautions................................................. 65Ordering, Receiving & Handling................. 65Scheduling / Unloading / Placing /

Sequence..................................... 66

Storing........................................................ 67SITE PREPARATION...................................... 69Excavation.................................................. 69Trenchwater................................................ 70Bedding/grade.............................................70

INSTALLATION............................................... 73Box Alignment............................................. 73Box Placement............................................ 73Jointing....................................................... 73Connecting the Boxes................................. 75Completion.................................................. 76Backll........................................................ 76Minimum Cover For Construction Loads.... 77Visual Inspection......................................... 78

III. SPECIFICATIONS ........................................79

IV.APPENDIX...................................................... 87Denitions................................................... 87Feet Head of Water into Pressure,

Pounds Per Square Inch...............90Feet Head of Water into

Kilopascals (kN/m2)........................90


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I.CONCRETEPIPEINSTALLATIONMANUALINTRODUCTION

This manual presents a guide for the proper in-stallation of concrete pipe. For many years, theAmerican Concrete Pipe Association has conduct-ed comprehensive research and analysis of thefactors which affect the eld performance of con-crete pipe. The knowledge and benecial practices

gained through research and experience are pre-sented in this manual.While focusing on the construction of the pipe-

soil system, this manual also addresses those fac-tors critical to the completion of the entire system,from delivery of the concrete pipe to the jobsite, to

the acceptance of the installed pipeline.This manual is intended as a guide and is not tosupersede the project specications.


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PRE-CONSTRUCTION

PRECAUTIONS

Federal regulations covering safety for all typesof construction, including sewer and culvert instal-lations, are published in the Safety and Health Reg-ulations for Construction under the Department ofLabor, Occupational Safety and Health Administra-tion (OSHA). These regulations are applicable to

all prime contractors and subcontractors involved inany type of construction, including alterations andrepair work.

The installer should also review installation prac-tices with the engineers design assumptions, par-ticularly in relation to the use of trench boxes and

compaction requirements of the backll.ORDERING,RECEIVINGANDHANDLING

Although the ordering of materials is the contrac-tors responsibility, supplier and engineer familiaritywith the contractors proposed schedule will en-able better coordination to avoid mistakes and pos-

sible delays in pipe deliveries. Pipe manufactur-ers stock a wide range of pipe sizes and strengths,but production facilities must frequently be adaptedto meet specic project requirements, particularlywhen large quantities and/or special types of pipeare involved. Information required to initiate a pipe

order should be in writing and include:name and location of projectpipe size, laying length and strengthtotal footage of each type and size of pipetype of jointsize and quantity of manhole base sections,

riser sections, cone sections and grade ringslist of ttings and specials including radius pipe


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laying sequencerequired specicationsmaterial test requirements

joint material and quantityinvoicing instructionsThe pipe should be checked for the following in-

formation, clearly marked on each pipe section:specication designationpipe class or strength designationspan, rise, table number, top of box and de-sign earth cover for ASTM C 1433(M) or C1577(M), or AASHTO M259(M) or M273(M)box sectionsdate of manufacturename or trademark of the manufacturerfor reinforced pipe with elliptical or quadrantreinforcement orientation, the letters E or Q,respectively and top.

UNLOADING

Unloading of pipe should be coordinated with theconstruction schedule and installation sequence

to avoid re-handling and unnecessary equipmentmovement. Access to the jobsite shall be providedby the contractor to ensure that the pipe manufac-turers trucks can deliver pipe to the unloading areaunder their own power.

Each shipment of pipe is loaded, blocked and

tied down at the plant to avoid damage during tran-sit. However, it is up to the receiver to make cer-tain, damage has not occurred in delivery from theplant to the construction site. An overall inspectionof each pipe shipment should be made on arrival,before the pipe is unloaded. Total quantities of

each item should be checked against the deliveryslip and any damaged or missing items recorded on


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AUTOMATIC UNLOADER

the delivery document.If a pipe is damaged during delivery or unload-

ing, the pipe should be set aside. Damaged ends,

chips or cracks, which do not pass through the wall,can usually be repaired.Many carriers are equipped with automatic un-

loaders, which further expedite the unloading of cir-cular pipe. These automatic unloaders consist ofa forklift type of apparatus mounted at the rear of aat bed truck. The forks rotate vertically rather thanmove up and down, such that, when the forks are ina vertical position they extend above the truck bed.This provides a backstop and cushion for the pipesections as they are rolled to the rear of the truckfor unloading. A cradle formed by the forks andunloader frame securely retains the pipe sectionbeing unloaded as the forks are rotated downwardand lowered to the ground.

Unloading of the pipe should be controlled so asnot to collide with the other pipe sections or ttings,and care should be taken to avoid chipping or spall-ing, especially to the spigots and bells. Cautionshould be exercised to be sure personnel are out of


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the path of the pipe as it is lowered.If the pipe has to be moved after unloading, the

sections should be rolled or lifted and should never

be dragged. Pipe sections should not be rolledover rough or rocky ground.The use of mechanical equipment is necessary

for unloading arch, elliptical and box sections andlarger size circular pipe, and can usually simplifyand speed up the unloading of smaller pipe. Whenusing mechanical equipment for unloading, thelifting device, which connects to the pipe, shouldenable proper and safe handling without damageto the pipe. Lifting devices such as slings, chain,steel wire, cable and rope should be placed aroundthe pipe and arranged so that the pipe is lifted in ahorizontal position. If the lifting device could chipor damage the pipe, padding should be providedbetween the pipe and lifting device. These typesof lifting devices should not be passed through thepipe. Other devices, which are designed to passinto or through the pipe, should not touch the spig-ot or bell jointing surfaces, and should extend farenough beyond the end of the pipe for adequateclearance of lifting lines.

When pipe is provided with lifting holes, the lift-ing device should pass through the wall and distrib-ute the weight along the inside barrel of pipe.

The most common lifting device for use with lift-ing holes consists of a steel threaded eye bar witha wing type nut and bearing plate. If a specially de-signed lifting device is not readily available, a singlelooped sling can be passed through the lift hole intothe bore of the pipe and then around a piece of tim-ber of adequate length and cross-section to assurestructural stability. For manhole sections, conesections, bases, ttings and other precast appur-


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American Concrete Pipe Association www.concrete-pipe.org10

LIFT HOLD DEVICES

tenances, the lifting holes or lifting eyes providedshould be used.

Regardless of the method used to unload pipe,

precautions should be taken to avoid damage tothe pipe and assure the pipe is unloaded in a safemanner.

STOCKPILING

Any stockpiling of pipe should be as near as

possible to where the pipe will be installed. Smalldiameter pipe should be layered in the same man-ner as they were loaded on the truck. The bottomlayer should be placed on a at base, adequatelyblocked to prevent shifting as more layers are add-ed. Each layer of bell and spigot pipe should be

arranged so that all the bells are at the same end.The bells in the next layer should be at the oppositeend, and projecting beyond the spigots of the pipesections in the lower layer. Where only one layeris being stockpiled, the bell and spigot ends shouldalternate between the adjacent pipe sections. All

pipes should be supported by the pipe barrel sothat the joint ends are free of load concentrations.Pipe sections generally should not be stockpiled at


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American Concrete Pipe Association www.concrete-pipe.org 11

the job site in a greater number of layers than wouldresult in a height of 6 ft. (2 m).

All exible gasket materials not cemented to

the pipe, including joint lubrication compounds,should be stored in a cool dry place to be distrib-uted as needed. Rubber gaskets and preformed orbulk mastics should be kept clean, away from oil,grease, and excessive heat and out of the directrays of the sun.


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INSTALLATION

LINEANDGRADE

For sewer and culvert construction, line andgrade are usually established by one or a combina-tion of the following methods:

reference line established by a helium-neonlasercontrol points consisting of stakes, spikes,

plugs or shiners set at the ground surface andoffset a certain distance from the proposedsewer centerlinecontrol points established at the trench bottomafter the trench is excavated.trench bottom and pipe invert elevations while

excavation and pipe installation progressesSpecially designed helium-neon lasers are avail-

able for sewer and culvert construction. Basicallythe instrument converts input power into a beam oflight, which is projected as a narrow beam ratherthan shining in all directions as does a light bulb.

The light beam is a continuous, uninterrupted stringline, which does not sag and can be used for dis-tances up to 1,000 ft. (90 to 150 m). The laser proj-ects a beam of light the diameter of which dependson the distance being projected and on the opticsof the particular instrument. Usually the beam is

about the size of a pencil. Since the laser beamis a light beam, it is seen by either looking back atthe instrument or intercepting the beam with target,which reects the light.

As with any surveying instrument, the initial set-ting is most important. But once a laser is set as

to direction and grade, it provides a constant refer-ence line from which measurements can be takenat any point along the beam. A workman with any


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ordinary rule or stadia rod can measure offsets forconstruction quickly and accurately, generally with-in 1/16 in. (1.58 mm) or less. The laser instrument

can be mounted in a manhole, set on a tripod orplaced on a solid surface to project the light beameither inside or outside the pipe.

The low-powered helium-neon laser used in

LASER SYSTEM


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construction is not considered to be a dangerousinstrument. Although anyone deliberately staringinto a 1 to 3 milliwatt laser for a sufcient time could

receive damage to the eye (that is comparable tostaring directly into the sun, or a welders arc).When pipe is installed by the jacking or tunneling

method of construction, an accurate control pointmust be established at the bottom of the jacking pitor work shaft. Close control of horizontal and verti-cal alignment can be obtained by a transit or laser.If excavation and pipe installation extend severalhundred feet (meters) from one shaft, or the hori-zontal alignment is curved, vertical line pipes canbe driven from the surface through which plumblines can be dropped. In many cases vertical holesare drilled from the surface for lubricating the out-side of the pipe or grouting and these can be usedto check line and grade.

Where control points are established at the sur-face and offset, batter boards, tape and level, orspecially designed transfer instruments are used totransfer line and grade to the trench bottom. Re-gardless of the specic type of transfer apparatusused, the basic principles are:

stakes, spikes, plugs or shiners as controlpoints are driven ush with the ground surfaceat 25 to 50 ft. (7.5 to 15 m) intervals for straight

alignment with shorter intervals for curvedalignmentoffset the control points 10 ft. (3 m) or otherconvenient distance on the opposite side ofthe trench from which excavated material willbe placeddetermine control point elevations by meansof a level, transit or other leveling device andindicate on the guard stake driven next to the


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control point the depth from the control point tothe trench bottom or pipe invertby means of longer grade stakes, driven im-

mediately adjacent to the control points, a con-tinuous string line is tied to the grade stakes ata specic distance above the trench bottom orpipe invertafter the surface control points are set, a cutsheet is prepared listing reference points, sta-tioning, offset distance and vertical distancefrom the control points to the trench bottom orpipe invert

For narrow trenches a horizontal batter boardis spanned across the trench and adequately sup-ported at each end. The batter board is set level

at the same elevation as the string line and a naildriven in the upper edge at the centerline of thepipe. In many cases the batter board is used onlyas a spanning member with a short vertical boardnailed to it at the pipe centerline. A string line isthen pulled tight across a minimum of three batter

boards and line transferred to the trench bottomby a plumb bob cord held against the string line.Grade is transferred to the trench bottom by meansof a grade rod or other suitable vertical measuringdevice.

Where wide trenches are necessary, due to

large pipe sizes or sloped trench walls, the batterboard may not be able the span the width of exca-vation. In such cases, the same transfer principle isused, except that the vertical grade rod is attachedto one end of the batter board and the other end setlevel against the offset string line. The length of the

horizontal batter board is the same as the offset dis-tance and the length of the vertical grade rod is thesame distance between the trench bottom or pipe


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invert and the string line. Specially designed instru-ments are available which incorporate a measuringtape, extendable arm and leveling device. These

instruments are based on the same principle, buteliminate the need to construct batter boards andsupports and are portable.

The transfer of surface control points to stakesalong the trench bottom is sometimes necessarybecause of the deep trenches or unstable soils re-quiring the trench sides to be sloped back. Stakesshould be set along the trench bottom at 50 ft. (15m) intervals and a string line drawn between two

EXAMPLE BATTER BOARD SET-UP

GradeStake

Grade Rod RegisteringGrade of Invert

BatterBoard

Grade

String

Grade Rod RegisteringGrade of Trench


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or three control points. Where line and grade areestablished as excavation proceeds, a transit, levelor laser setup is usually used.

In setting line and grade for culverts installed atabout the same elevation as the original ground,culvert control points are usually established duringthe construction survey. Stakes are then set alongthe culvert length by means of a hand level or sur-vey instrument. If the embankment is rst built upand then a sub-trench excavated, the same proce-dures as for trench excavations can be used.

EXCAVATIONLIMITS

The most important excavation limitations aretrench width and depth. As excavation progress-es, trench grades should be continuously checked

against the elevations established in the sewer orculvert prole. Improper trench depths can result inhigh or low spots in the line, which may adverselyaffect the hydraulic capacity of the sewer or culvertand require correction or additional maintenanceafter the line is completed.

The backll load transmitted to the pipe is direct-ly dependent on the trench width. To determinethe backll load, the designer assumes a certaintrench width and then selects a pipe strength ca-pable of withstanding this load. If the constructedtrench width exceeds the width assumed in design,

the pipe could be overloaded and possibly structur-ally distressed. Because the backll loads and pipestrength requirements are a function of the trenchwidth, maximum trench widths are usually estab-lished in the plans or standard drawings. Wheremaximum trench widths are not indicated in any of

the construction contract documents, trench widthsshould be as narrow as possible, with side clear-


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TRENCH WIDTH FOR CONCRETE PIPE

Pipe Trench Pipe TrenchDiameter Width Diameter Width(inches) (feet) (millimeters) (millimeters)

4 1.6

6 1.8

8 2.0

10 2.3

12 2.5

15 3.0

18 3.4

21 3.8

24 4.1

27 4.5

33 5.2

36 5.6

42 6.3

48 7.0

54 7.8

60 8.5

66 9.2

72 10.0

78 10.7

80 11.4

90 12.196 12.9

102 13.6

108 14.3

114 14.9

120 15.6

126 16.4

132 17.1138 17.8

144 18.5

100 470

150 540

200 600

250 680

300 800

375 910

450 1020

525 1100

600 1200

675 1300

825 1600

900 1700

1050 1900

1200 2100

1350 2300

1500 2500

1650 2800

1800 3000

1950 3200

2100 3400

2250 3600

2400 3900

2550 4100

2700 4300

2850 4500

3000 4800

3150 5000

3300 52003450 5400

3600 5600

NOTE: Trench widths based on 1.25 Bc

+ 1 ft. (1.25 Bc

+ 300mm) where Bc

is theoutside diameter of the pipe in inches (mm).


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ance adequate enough to insure proper compac-tion of backll material at the sides of the pipe. Thefollowing trench widths can be used as a general

guide for circular concrete pipe:EXCAVATEDMATERIAL

If excavated material is to be stored on top of thepipeline, special consideration should be given tosurcharge loading during the design of the pipe.

Stockpiling excavated material adjacent to the

trench causes a surcharge load, which may cave inthe trench walls. The ability of the trench walls tostand vertically under this additional load dependson the cohesive characteristics of the particular typeof material being excavated. This surcharge loadshould be considered when evaluating the need to

provide trench support. It may be necessary wheredeep or wide trenches are being excavated to haulaway a portion of the excavated soil or spread thestockpile with a bulldozer or other equipment. Ifthe excavated material is to be used as backll, thestockpiled material should be visually inspected

for rocks, frozen lumps, highly plastic clay or otherobjectionable material. If the excavated soil differssignicantly from the intended backll material setforth in the plans, it may be necessary to haul theunsuitable soil away and bring in select backll ma-terial.

DEWATERING

Control of surface and subsurface water is re-quired so that dry conditions will be provided dur-ing excavation and pipe laying. Ground waterconditions should be investigated before they are

encountered during the course of excavation.


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STANDARDINSTALLATIONS

Through consultations with contractors and engi-neers, four Standard Installations were developed

and are presented in the following pages. The fol-lowing ideas, formulated from past experience, wereconrmed with parameter studies. These StandardInstallations represent an improved understand-ing of the installation factors effecting pipe perfor-mance and reect modern construction techniques.

They are designed to improve pipe performance byemphasizing benecial construction and installa-tion requirements. By providing installations, whichutilize a wide range of backll materials, includingnative materials, the Standard Installations offer theowner, engineer, and contractor more versatility in

selecting the installation to meet their unique com-bination of site conditions, backll materials and de-sired construction and inspection materials. Someof the ideas included in the Standard Installationsconrm the following concepts:

The soil in the haunch area from the foundation

to the pipe springline provides signicant sup-port to the pipe and reduces pipe stresses.Loosely placed, uncompacted bedding directlyunder the invert of the pipe signicantly reduc-es stresses in the pipe.Installation materials and compaction levels

below the springline have a signicant effecton pipe structural requirements.Soil in those portions of the bedding andhaunch areas directly under the pipe is difcultto compact.Compaction level of the soil directly above the

haunch, from the pipe springline to the topof the pipe grade level, has negligible effect


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on pipe stresses. Compaction of the soil inthis area is not necessary unless required forpavement structures.

These Standard Installations identify four prin-cipal zones surrounding the lower half of the pipe,which are critical to the pipe-soil system. The four

zones are the middle bedding, the outer bedding,the haunch and the lower side. The type of ma-terial (based on soil characteristics) and level of

compaction, and the material utilized in construc-tion of these important zones varies with the instal-

lation type 1, 2, 3 and 4.

PIPE/INSTALLATIONTERMINOLOGY

Do

Di

Bottom

Crown

Foundation

(Existing Soil or Compacted Fill)

Bedding

Springline

H

Haunch

Top

LowerSide

Overfill


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Do

Do/6 (Min.)Do (Min.)

Do/3

Di

Middle bedding looselyplaced uncompactedbedding except Type 4

Outer bedding materials andcompaction each side, same

requirements as haunch

Foundation

BeddingSee Tables 1 & 2

H

Haunch

Lower SideSpringline

Overfill Soil

Category I, II, III

STANDARDTRENCH/EMBANKMENTINSTALLATION

SIDD Standard ModifiedSoil USCS AASHTO Proctor Proctor

Representative Soil Types Percent Compaction

Gravellysand

(Category I)

SandySilt

(Category II)

SiltyClay

(Category III)

SW, SPGW, GP

GM, SM, MLAlso GC, SC

with less than20% passing#200 sieve

CL, MHGC, SC

A1, A3

A2, A4

A5, A6

1009590858061

1009590858049

10095

90858045

EQUIVALENT USCS AND AASHTO SOILCLASSIFICATIONS FOR SIDD SOIL DESIGNATIONS

959085807559

959085807546

9085

80757040


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Installation Bedding Haunch and LowerType Thickness Outer Bedding Side

Type 1

Type 2

Type 3

Type 4

D0/24 minimum,not less than 3in.If rock foundation,

use D0/12 minimum;not less than 6in.

D0/24 minimum,not less than 3in.

If rock Foundation,use D0/12 minimum;

not less than 6in.


use D0/12 minimum,not less than 6in.


use D0/12 minimum,not less than 6in.

95% Category I

90% Category Ior

95% Category II

85% Category I,90% Category II,

or95% Category III

No compactionrequired, exceptif Category III, use85% Category III

90% Category I,95% Category II

or100% Category III

85% Category I,90% Category II

or95% Category III

85% Category I,90% Category II,

or95% Category III

No compactionrequired, exceptif Category III, use85% Category III

STANDARD INSTALLATIONS SOILS ANDMINIMUM COMPACTION REQUIREMENTS

Notes:

1. Compaction and soil symbols - i.e. 95% Category I- refers to Category I soil material

with minimum standard Proctor compaction of 95%. See Table 1 for equivalent modified

Proctor values.

2. Soil in the outer bedding, haunch, and lower side zones, except under the middle 1/3 ofthe pipe, shall be compacted to at least the same compaction as the majority of soil in

the overfill zone.

3. For trenches, top elevation shall be no lower than 0.1 H below finished grade or, for

roadways, its top shall be no lower than an elevation of 1 foot below the bottom of the

pavement base material.

4. For trenches, width shall be wider than shown if required for adequate space to attain the

specified compaction in the haunch and bedding zones.

5. For trench walls that are within 10 degrees of vertical, the compaction or firmness of the

soil in the trench walls and lower side zone need not be considered.

6. For trench walls with greater than 10 degree slopes that consist of embankment, thelower side shall be compacted to at least the same compaction as specified for the soil in

the backfill zone.

7. Subtrenches

3.1 A subtrench is defined as a trench with its top below finished grade by more

than 0.1 H or, for roadways, its top is at an elevation lower than 1ft. below the

bottom of the pavement base material.

3.2 The minimum width of a subtrench shall be 1.33 Do or wider if required for

adequate space to attain the specified compaction in the haunch and bedding

zones.

3.3 For subtrenches with walls of natural soil, any portion of the lower side zone inthe subtrench wall shall be at least as firm as an equivalent soil placed to the

compaction requirements specified for the lower side zone and as firm as the

majority of soil in the overfill zone, or shall be removed and replaced with soil

compacted to the specified level.


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HORIZONTALELLIPTICALPIPESTANDARDEMBANKMENTINSTALLATIONS

HORIZONTALELLIPTICALPIPESTANDARDTRENCHINSTALLATIONS

Do

Do/6 (min.)Do(Min.)

Do/3 Middle Bedding looselyplaced uncompactedbedding

Foundation

Springline

H

HaunchSee Table

LowerSideSee Table

Overfill Soil Category I, II, III

Outer bedding material andcompaction each side, same


Bedding See Table

Overfill SoilCategory I, II, III

Do

Do/6 (min.)Do(Min.)

Do/3Middle Bedding looselyplaced uncompactedbedding

Foundation

Springline

H

HaunchSee Table

LowerSide

See Table



Bedding See Table


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VERTICALELLIPTICALPIPESTANDARDEMBANKMENTINSTALLATIONS

VERTICALELLIPTICALPIPESTANDARDTRENCHINSTALLATIONS

Do

Do/6 (min.)Do(Min.)


Foundation

Springline

H

HaunchSee Table

LowerSideSee Table




Bedding See Table


Do

Do/6 (min.)Do(Min.)


Foundation

Springline

H

HaunchSee Table

LowerSide

See Table



Bedding See Table


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ARCHPIPESTANDARDEMBANKMENTINSTALLATIONS

ARCHPIPESTANDARDTRENCHINSTALLATIONS

Do

Do/6 (min.)Do(Min.)


Foundation

Springline

H

HaunchSee Table

LowerSideSee Table




Bedding See Table


Do

Do/6 (min.)Do(Min.)


Foundation

Springline

H

HaunchSee Table

LowerSide

See Table



Bedding See Table


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For those projects still using the older beddingtypes, bedding types, A, B, C and D are present-ed.

CLASSABEDDINGCONCRETE CRADLE

CONCRETE CRADLE Used only with circularpipe, the pipe is bedded in non-reinforced or re-inforced concrete having a thickness, d, as listed,

and extending up the sides for a height equal to theoutside diameter. The cradle should have a mini-mum width at least equal to the outside diameterof the pipe plus 8 in. (200 mm). The backll abovethe cradle is densely compacted and extends 12in. (300 mm) above the crown of the pipe. In rock,

especially where blasting is likely in the adjacentvicinity, the concrete cradle should be cushionedfrom the shock of the blasting which can be trans-mitted through the rock.

CLASSBBEDDING

SHAPED OR UNSHAPED

GRANULAR FOUNDATION

SHAPED For a shaped subgrade with granularfoundation, the bottom of the excavation is shapedto conform to the pipe surface but at least 2 in. (50mm) greater than the outside dimensions of the

pipe. The width should be sufcient to allow 6/10of the outside pipe diameter for circular pipe, 7/10of the outside span for arch and elliptical pipe, andthe full bottom width of box sections to be beddedin ne granular ll placed in the shaped excavation.Densely compacted backll should be placed at the

sides of the pipe to a depth of at least 12 in. (300mm) above the top of the pipe.


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UNSHAPED A granular foundation withoutshaping is used only with circular pipe. The pipe isbedded in compacted granular material placed on

the at trench bottom. The granular bedding hasa minimum thickness, d, as listed and should ex-tend at least halfway at the sides. The remainderof the side lls, and a minimum depth of 12 in. (300mm) over the top of the pipe, should be lled withdensely compacted material.

CLASSCBEDDINGSHAPED SUBGRADE OR

GRANULAR FOUNDATION

SHAPED SUBGRADE The pipe is beddedwith ordinary care in a soil foundation, shaped to t

the lower part of the pipe exterior with reasonablecloseness for a width of at least 50 percent of theoutside diameter for a circular pipe, and 1/10 of theoutside pipe rise for arch pipe, elliptical pipe andbox sections. For trench installations the sides andarea over the pipe are lled with lightly compacted

backll to a minimum depth of 6 in. (150 mm) abovethe top of the pipe. For embankment installationsthe pipe should not project more than 90 percent ofthe vertical height of the pipe above the bedding.

GRANULAR FOUNDATION Used only withcircular pipe, the pipe is bedded in compactedgranular material or densely compacted backllplaced on a at bottom trench. The bedding mate-rial should have a minimum thickness as indicatedand should extend up the sides for a height of atleast 1/6 the outside diameter. For trench instal-lations the sidell and area over the pipe to a mini-mum depth of 6 in. (150 mm) should be lled withlightly compacted backll.


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CLASSDBEDDING

Used only with circular pipe, little or no care isexercised either to shape the foundation surface to

t the lower part of the pipe exterior, or to ll allspaces under and around the pipe with granularmaterials. However, the gradient of the bed shouldbe smooth and true to established grade. Thisclass of bedding also includes the case of pipe onrock foundations in which an earth cushion is pro-

vided under the pipe but is so shallow that the pipe,as it settles under the inuence of vertical load, ap-proaches contact with the rock.


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EMBANKMENTBEDDINGCIRCULARPIPE(INCHES)

Bc

FLAT SUBGRADECLASS D

Bc

0.6 Bc

Bc+ 8" min.

pBcpmax.=0.5

pBcpmax.=0.3

0.1 Bc

0.3 Bc

pBcpmax.=0.7

1.25 Bcmin.

1/4 Bc

1/4 Min

CONCRETE CRADLECLASS A

CompactedGranularMaterial

CompactedSoil

Fine GranularFill Material

2" min.

Bc

SHAPED SUBGRADE WITHGRANULAR FOUNDATION

GRANULARFOUNDATION

Bc

d

pBcpmax.=0.8

1.25 Bcmin.

CompactedGranularMaterialDenselyCompactedBackfill

GRANULARFOUNDATION

Bc

d

LegendBc= outside diameterH = backfill cover above top of pipeD = inside diameterd = depth of bedding material

below pipe

0.5 Bc

Bc


CLASS C

CLASS B

Notes:For Class B and C beddings, subgrades shouldbe excavated or over excavated, if necessary,so a uniform foundation free of protrudingrocks may be provided.Special care may be necessary with Class A orother unyielding foundations to cushion pipefrom shock when blasting can be anticipated inthe area.

Depth of BeddingMaterial Below Pipe

D d(min)27" & smaller 3"30" to 60" 4"66" & larger 6"


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EMBANKMENTBEDDINGCIRCULARPIPE(MILLIMETERS)

Bc

0.6 Bc

Bc+200mm min.

pBcpmax.=0.5

pBcpmax.=0.3

0.1 Bc

0.3 Bc

pBcpmax.=0.7

1.25 Bcmin.

1/4 Bc

1/4 Min

CONCRETE CRADLECLASS A


Bc


GRANULARFOUNDATION

Bc

d

pBcpmax.=0.8

1.25 Bcmin.

CompactedGranularMaterialDenselyCompactedBackfill

GRANULARFOUNDATION

Bc

d


below pipe

0.5 Bc

Bc

Bc


CLASS C

CLASS B

Notes:For Class B and C beddings, subgrades shouldbe excavated or over excavated, if necessary,so a uniform foundation free of protrudingrocks may be provided.Special care may be necessary with Class A orother unyielding foundations to cushion pipefrom shock when blasting can be anticipated inthe area.


D d(min)675mm & smaller 75mm750mm to 1,500mm 100mm1,650mm & larger 150mm

CompactedSoil

Fine GranularFill Material50mm min.


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TRENCHBEDDINGCIRCULARPIPE(INCHES)


below pipeAs

= area of transverse steel in thecradle of arch expressed as apercentage of area of concreteat invert or crown

Notes:For Class A bedding, use d as depth ofconcrete below pipe unless otherwiseindicated by soil or design conditions.For Class B and C beddings, subgradesshould be excavated or over excavated,if necessary, so a uniform foundationfree of protruding rocks may be provided.Special care may be necessary with Class Aor other unyielding foundations to cushionpipe from shock when blasting can beanticipated in the area.

Bc

1-1/4 Bc

0.6 Bc

Bc+8" min.

1/4 Bcd(see notes)

12" min.

CONCRETE CRADLE

1/8 H6" min.

LightlyCompacted

Backfill

Loose

Backfill

DenselyCompacted

Backfill

DenselyCompacted Backfill

Plain orReinforcedConcrete 12,000 psi min.

Compacted GranularMaterial or DenselyCompacted Backfill

CompactedGranular Material

Fine Granular FillMaterial 50mm min.

1/8 H6" min.

1/8 H6" min.

Bc

12" min. 12"


GRANULAR FOUNDATION

Bc

d

FLAT SUBGRADECLASS DBf= 1.1

CLASS AReinforced As= 1.0% Bf= 4.8Reinforced As= 0.4% Bf= 3.4Plain Bf= 2.8

CLASS BBf= 1.9

Bc

0.5 Bc

Bc

SHAPED SUBGRADE GRANULAR FOUNDATION

Bc

d1/6 Bc


D d(min)

27" & smaller 3"30" to 60" 4"66" & larger 6"


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TRENCHBEDDINGCIRCULARPIPE(MILLIMETERS)

Notes:For Class A bedding, use d as depth ofconcrete below pipe unless otherwiseindicated by soil or design conditions.For Class B and C beddings, subgradesshould be excavated or over excavated,if necessary, so a uniform foundationfree of protruding rocks may be provided.Special care may be necessary withClass A or other unyielding foundationsto cushion pipe from shock when blastingcan be anticipated in the area.

Bc

1-1/4 BcBc+200mm min.

1/4 Bcd(see notes)

300mm min.

CONCRETE CRADLE

DenselyCompacted Backfill

Plain orReinforcedConcrete 113,800 kPa min.

0.6 Bc

1/8 H

150mm min.

LightlyCompacted

Backfill

Loose

Backfill

DenselyCompacted

Backfill

Compacted GranularMaterial or DenselyCompacted Backfill

CompactedGranular Material


1/8 H150mm min.

1/8 H

150mm min.

Bc

300mm min. 300mm.


GRANULAR FOUNDATION

Bc

d

FLAT SUBGRADECLASS DBf= 1.1


below pipeAs

= area of transverse steel in thecradle of arch expressed as apercentage of area of concreteat invert or crown

CLASS AReinforced As= 1.0% Bf= 4.8Reinforced As= 0.4% Bf= 3.4Plain Bf= 2.8

CLASS BBf= 1.9

Bc

0.5 Bc

Bc

SHAPED SUBGRADE GRANULAR FOUNDATION

Bc

d1/6 Bc


D d(min)675mm & smaller 75mm750mm to 1,500mm 100mm1,650mm & larger 150mm


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TRENCHBEDDINGSELLIPTICAL&ARCHPIPE(INCHES)

0.7Bc

0.7Bc

Bc

Bc


Shapedto Fit

Shapedto Fit

Shapedto Fit

LightlyCompacted

Backfill

LightlyCompacted

Backfill

LightlyCompacted

Backfill

FineGranular Fill

Material2" min.


FineGranular FillMaterial2" min.

12"

0.7Bc

BcCompactedGranularMaterial

FineGranular FillMaterial2" min.

0.5 Bc

0.5Bc

Bc

Bc

6"

HORIZONTAL ELLIPTICAL PIPE

VERTICAL ELLIPTICAL PIPE

ARCH PIPE

12" 6"

12" 6"

CLASS BBf=1.9

CLASS CBf=1.5

CLASS B

Bf=1.9

CLASS C

Bf=1.5

CLASS BBf=1.9

0.7Bc

Bc

CLASS BBf=1.5


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TRENCHBEDDINGSELLIPTICAL&ARCHPIPE(MILLIMETERS)

0.7Bc

0.7Bc

Bc

Bc


Shapedto Fit

Shapedto Fit

LightlyCompacted

Backfill

LightlyCompacted

Backfill

Shapedto Fit

LightlyCompacted

Backfill

FineGranular Fill

Material50mm min.


FineGranular FillMaterial50mm min.

300mm

0.7Bc

Bc


FineGranular FillMaterial50mm min.

300mm

300mm

0.5 Bc

0.5Bc

Bc

Bc

150mm

0.5Bc

Bc

150mm

150mm



ARCH PIPE

CLASS B

Bf=1.9CLASS C

Bf=1.5

CLASS B

Bf=1.9

CLASS C

Bf=1.5

CLASS B

Bf=1.9CLASS C

Bf=1.5


35/90


EMBANKMENTBEDDINGSELLIPTICAL&ARCHPIPE(INCHES)

Bc Bc

pB'cpmax.=0.7

B'cB'c

B'c

0.3 B'c

H H

0.1 B'c

Bc Bc

Shaped to Fit

Shaped to Fit

Shaped to Fit

Fine Granular FillMaterial 2" min.



ARCH PIPE

CLASS B

pB'cpmax.=0.7

pB'c

pB'c

pB'c

B'c B'c

0.3 B'c

H H

0.1 B'c 0.1 B'c

0.1 B'c

0.1 B'c

Fine Granular FillMaterial 2" min.

CLASS B CLASS C

CLASS C

Bc Bc

pB'cpmax.=0.7

B'c

0.3 B'c

H H

0.1 B'cFine Granular FillMaterial 2" min.

CLASS BCLASS C


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EMBANKMENTBEDDINGSELLIPTICAL&ARCHPIPE(MILLIMETERS)

Bc Bc

pB'cpmax.=0.7

B'cB'c

B'c

0.3 B'c

H H

0.1 B'c

Bc Bc

Shaped to Fit

Shaped to Fit

Shaped to Fit




ARCH PIPE

CLASS B

pB'cpmax.=0.7

pB'c

pB'c

pB'c

B'c B'c

0.3 B'c

H H

0.1 B'c 0.1 B'c

0.1 B'c

0.1 B'c


CLASS B CLASS C

CLASS C

Bc Bc

pB'cpmax.=0.7

B'c

0.3 B'c

H H

0.1 B'cFine Granular FillMaterial 50mm min.

CLASS BCLASS C


37/90


JOINTING

Placement of pipe should start at the outlet endof the line of pipe sections. The bell end should

point upstream and the spigot or tongue shouldpoint downstream. This helps prevent bedding ma-terial from being forced into the bell during jointingand enables easier coupling of pipe sections.

Several types of joints and sealant materials areutilized for concrete pipe to satisfy a wide range of

performance requirements. All of the joints are de-signed for ease of installation and the manufactur-ers recommendations regarding jointing proceduresshould be closely followed to assure resistance toinltration of ground water and/or backll materialsand exltration of sewage or storm water.

The most common compression joint sealantsand joint llers used for sanitary sewers, stormsewers and culverts are:

rubber, attached or separatemasticbulk or preformed mortar

lter fabricexternal bands, cement or rubber

Regardless of the specic type of joint sealantused, each joint should be checked to be sure allpipe sections are in a home position. For jointssealed with rubber gaskets, it is important to follow

the manufacturers installation recommendations toassure that the gasket is properly positioned andunder compression.

The pipe manufacturer should recommend amaximum joint opening.

Rubber

There are numerous types of rubber gasketsused by pipe manufacturers. It is important that the


38/90


gasket and/or pipe manufacturers recommendedprocedures be followed for every section of pipebeing installed. Illustrations are intended only as

CLEANBELL

CLEANSPIGOT

Carefully clean all dirtand foreign substancesfrom the jointing surfaceof the bell or groove endof pipe.

Improperly prepared belljointing surface mayprevent homing of thepipe.

Carefully clean spigot ortongue end of pipe,

including the gasketrecess.

Improperly preparedspigot and gasket recess

may prevent gasketfrom sealing correctly.


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LUBRICATEBELL

LUBRICATESPIGOT

Lubricate bell jointingsurface liberally. Use abrush, cloth, sponge orgloves to cover entire

surface. Only approvedlubricant should be used.

A bell not lubricated orimproperly lubricatedmay cause gasket to rolland possibly damage

the bell.

Lubricate the spigot ortongue end of pipe,especially the gasketrecess.

Gasket may twist out ofrecess if lubricant inrecess is lacking orinsufficient.


40/90


LUBRICATEGASKET

INSTALLGASKET

Lubricate the gasketthoroughly before it isplaced on the spigot ortongue.

Excess force will berequired to push thepipe to the homeposition if gasket is not

well lubricated.

Fit the gasket carefully.Equalize the rubbergasket stretch by runninga smooth, round object,inserted between gasket

and spigot, around theentire circumferenceseveral times.

Unequal stretch couldcause bunching ofgasket and may causeleaks in the joint orcrack the bell.


41/90


a guide and do not replace or supersede projectspecications, contract documents, or specicmanufacturers recommendations.

Mastic

Mastic sealants consist of rubber compounds orbitumen and inert mineral ller, which are usuallyapplied at ambient temperatures. The joint surfac-es are thoroughly cleaned, dried and prepared in

accordance with the manufacturers recommenda-tions. A sufcient amount of sealant should be usedto ll the annular joint space with some squeezeout. During cold weather, better workability of themastic sealant can be obtained if the mastic and

joint surfaces are warmed.

MortarMortar consists of portland cement paste, sand

ALIGNPIPE

Align bell and spigot ofpipes to be jointed. Beforehoming the joint, checkthat the gasket is in

contact with the entrytaper around the entirecircumference.

Improper alignment candislodged gasketcausing leaks orpossibly break the bell.


42/90


and water. The joint surface is thoroughly cleanedand soaked with water immediately before the jointis made. A layer of paste or mortar is placed in the

lower portion of the bell or groove end of the in-stalled pipe and on the upper portion of the tongueor spigot end of the pipe section to be installed.The tongue or spigot is then inserted into the bellor groove of the installed pipe until some mortar issqueezed out. Any annular joint space betweenthe adjacent pipe ends is lled with mortar and theexcess mortar on the inside of the pipe wiped andnished to a smooth surface.

GeotextileFilterFabrics

As an alternative measure, where groundwaterand joint congurations warrant, a band of geotex-

tile lter fabric, usually 1 to 2 feet (.3 to .6 meters)wide may be wrapped around the exterior of thepipe joint and secured with either tape or stitchingto prevent soil inltration into joints of storm andculvert pipe.

ExternalBandsPortland cement mortar bands are sometimes

specied around the exterior of the pipe joint. Aslight depression is excavated in the bedding ma-terial to enable mortar to be placed underneaththe pipe. The entire external joint surface is then

cleaned and soaked with water. Special canvas orcloth diapers can be used to hold the mortar as itis placed. Backll material should be immediatelyplaced around the pipe.

Rubber-mastic bands also can be used aroundthe exterior of the pipe joint. The bands are stretched

tightly around the barrel of the pipe and held rmlyin place by the weight of the backll material.


43/90


JOINTPROCEDURES

Joints for pipe sizes up to 24 in. (600 mm) indiameter can usually be assembled by means of a

bar and wood block. The axis of the pipe section tobe installed should be aligned as closely as possi-ble to the axis of the last installed pipe section, andthe tongue or spigot end inserted slightly into thegroove or bell. A bar is then driven into the beddingand wedged against the bottom bell or groove end

of the pipe section being installed. A wood blockis placed horizontally across the end of the pipe toact as a fulcrum point and to protect the joint endduring assembly. By pushing the top of the verti-cal bar forward, lever action pushes the pipe into ahomed position.

When jointing small diameter pipe, a chain orcable is wrapped around the barrel of the pipe a fewfeet behind the tongue or spigot and fastened with

a grab hook or other suitable connecting device. Alever assembly is anchored to the installed pipe,several sections back from the last installed sec-


44/90


tion, and connected by means of a chain or cableto the grab hook on the pipe to be installed. Bypulling the lever back, the tongue or spigot of the

pipe being jointed is pulled into the bell or grooveof the last installed pipe section. To maintain closecontrol over the alignment of the pipe, a laying slingcan be used to lift the pipe section slightly off thebedding foundation.

When jointing larger diameter pipe, when gran-

ular bedding is used, mechanical pipe pullers arerequired. Several types of pipe pullers or come-along devices have been developed but the basicforce principles are the same.

Large diameter pipe can be jointed by placing adead man blocking inside the installed pipe, sev-

eral sections back from the last installed section,

which is connected by means of a chain or cableto a strong back placed across the end of the pipesection being installed. The pipe is pulled home bylever action similar to the external assembly.

Mechanical details of the specic apparatusused for pipe pullers or come-along devices mayvary, but the basic lever action principle is used to


45/90


develop the necessary controlled pulling force.The use of excavating equipment to push pipe

sections should be done with extreme caution. The

force applied by such equipment can damage thepipe. Direct contact between installation machineryand the pipe is prohibited. Use appropriate cushionmaterial between the pipe and the machine to pre-vent spalling.

SERVICECONNECTIONS

When a pipe connects to a rigid structure suchas a building, manhole or junction chamber, thebedding and foundation for the connecting pipesection should be highly compacted to minimizedifferential settlement. Differential settlement canresult in the pipe being sheared or cracked at the

connection. Special connectors are available whichprovide exibility between the connecting pipe andthe structure.

CURVEDALIGNMENT

Changes in direction of sewer lines are usually

accomplished at manhole structures, while gradeand alignment changes in concrete pipe sewerscan be incorporated into the line through the useof deected straight pipe, radius pipe or specials.Since manufacturing and installation feasibility aredependent on the particular method used to negoti-

ate a curve, it is important to establish the methodprior to trench excavation. For deected straightpipe the joint of each pipe section is opened up onone side while the other side remains in the homeposition. The difference between the home andopened joint space is generally designated as the

pull. The maximum permissible pull must be limitedto that opening which will provide satisfactory jointperformance. This varies for different joint congu-


46/90


rations and is best obtained from the pipe manu-facturer.

Radius pipe, also referred to as beveled or mi-

tered pipe, incorporates the deection angle into thepipe joint. The pipe is manufactured by shorteningone side of the pipe and the amount of shorten-ing for any given pipe is dependent on manufactur-ing feasibility. Because of the possibility of greaterdeection angles per joint, sharper curvature withcorrespondingly shorter radii can be obtained withradius pipe than with deected straight pipe.

When establishing alignment for radius pipe, therst section of radius pipe should begin within onehalf of a radius pipe length of the point of curva-ture, and the last section of the radius pipe shouldextend one half of a radius pipe length beyond thepoint of tangent, as shown in the illustrationAlign-

ment for Radius Pipe.Special precast sections can be used for ex-

tremely short radius curves which cannot be ne-gotiated with either deected straight pipe or withconventional radius pipe. Sharper curves can behandled by using special short lengths of radiuspipe rather than standard lengths.

One or more of these methods may be employedto meet the most severe alignment requirements.Since manufacturing processes and local standardsvary, local concrete pipe manufacturers should beconsulted to determine the availability and geomet-ric conguration of pipe sections to be installed oncurved alignment. In addition, many manufacturershave standardized joint congurations and deec-tions for specic radii and economies may be real-ized by using standard pipe.


47/90


CURVED ALIGNMENT

Deflected Straight Line

Radius Pipe

Bends


48/90


When radius pipe is used to negotiate a curve,

the point of curve (P.C.) should be established atthe midpoint of the last straight pipe and the point

of tangent (P.T.) falls one-half of the standard pipelength back from the straight end of the last radiuspipe. Incorrect alignment will result when the pointof curve is established at the end of the last section

of straight pipe. To assure the point of curve is atthe proper station it may be necessary for a special

short length of pipe to be installed in the line aheadof the point of curve.

ALIGNMENT FOR RADIUS PIPE

Last Straight Pipe

Set P.C.

Correct Alignment

P.T.D

irection

ofLayin

g


49/90


FINALBACKFILLING

Once the envelope of backll material is placedand properly compacted, the remainder of the ll or

backll should be placed and compacted to preventsettlement at the surface. Several types of com-paction equipment are available and certain typesare best for particular types of soils. The steelwheeled roller is best suited for compacting coarseaggregate such as slag, coarse gravel and graded

rock aggregates. The sheepsfoot roller is best forcohesive clays or silts, but is not suitable for useon granular soils. Specially designed rubber tiredrollers, which provide both static weight and knead-ing action, are applicable to many soils from claysto sand.

Regardless of the type of compaction equipmentused, the backll or ll material should be consis-tent with density requirements of the particular bed-ding specied.

ACCEPTANCETESTS

The physical tests included in the material speci-cations, under which the pipe is purchased, as-sure that pipe delivered to the job site meets or ex-ceeds the requirements established for a particularproject. The project specications usually includeacceptance test requirements to assure that rea-sonable quality control of workmanship and ma-terials has been realized during the constructionphase of the project. Soil density, line and grade,and visual inspection are all applicable tests for allstorm sewer, sanitary sewer and culvert projects.For sanitary sewers, limits are usually establishedfor inltration and exltration.


50/90


SOILDENSITY

Several test procedures have been developed formeasuring in-place soil densities and for cohesive

soils most of the methods are based on volumetricmeasurement. To correlate in-place soil densities

MOISTURE-DENSITY TEST

Compacted Sample

Removed from Hole

Moisture Content Percent

DensityPCF(kg/m3)

DensityPCF

(kg/m3)Max. Density

Max. Density

OptimumM.C.

12" (300mm)

5.5 lb (2.5 kg)Tamper

10 lb (4.5 kg)Tamper

18" (450mm)

OptimumM.C.

Moisture Content Percent

DETERMINATION OF VOLUME OF REMOVED SAMPLE

FIELD DENSITY TEST

STANDARD

MODIFIED

Dimensionsof HoleVariable

Fixed quantity ofsand with uniformgrain size. Ottawasand or equivalent

Cubic Meter1

1000

Cubic Foot1

30

Anchor SteelTemplate


51/90


with the maximum density of a particular soil, it isrst necessary to determine the optimum moisturecontent for maximum compaction and then use this

as a guide to determine the actual compaction ofthe ll or backll. The most common methods usedto determine optimum moisture content and maxi-mum density are the standard tests for moisture-density relations, frequently termed Standard Proc-tor Test and Modied Proctor Test.

ASTM and AASHTO Specications related tosoil density and moisture content are:

ASTM D 698 AASHTO T 99ASTM D 1557 AASHTO T 180ASTM D 2922 AASHTO T 238

LINEANDGRADE

Line and grade should be checked as the pipeis installed, and any discrepancies between the de-sign and actual alignment and pipe invert elevationsshould be corrected prior to placing the backll orll over the pipe. Obtaining manhole invert levels

for the preparation of as-built drawings, combinedwith visual inspection of the sewer or culvert, pro-vides an additional check that settlement has notoccurred during backll or ll operations.

VISUALINSPECTION

Larger pipe sizes can be entered and examinedwhile smaller sizes must be inspected visually fromeach manhole or by means of TV cameras. Follow-ing is a checklist for an overall visual inspection of asewer or culvert project:

debris and obstructionsexcessive cracks

joints properly sealedinvert smooth and free of sags or high points


52/90


stubs properly grouted and pluggedhookups, diversions and connections properlymade

catch basins and inlets properly connectedmanhole frames and covers properly installedsurface restoration and all other items perti-nent to the construction properly completed.

INFILTRATION

The inltration of excessive ground water into a

sanitary sewer can overload the capacity of a sew-er collection system and treatment facilities. The in-ltration test, conducted in accordance with ASTMC 969 (C 969M), is intended to demonstrate theintegrity of the installed materials and constructionprocedures, as related to the inltration of ground

water, and therefore, is only applicable if the watertable level is at least 2 ft. (600 mm) above the crownof the pipe for the entire length of the test section.Although the test is a realistic method of determin-ing water tightness, there are inherent difcultiesin applying the test criteria because of seasonal

uctuations in the water table and the problem ofcorrelating high ground water level conditions withactual test conditions.

Before conducting the test, the water table shouldbe allowed to stabilize such that water completelysurrounds the pipe during the test period. The test

is usually conducted between adjacent manholeswith the upstream end of the sewer bulkheaded ina suitable manner to isolate the test section. Allservice laterals, stubs and ttings should be prop-erly plugged or capped at the connection to thetest pipe section to prevent the entrance of ground

water at these locations. A V-notch weir or othersuitable measuring device should be installed in the


53/90


INFILTRATION

TEST


54/90


inlet pipe to the downstream manhole. Inltratingwater is then allowed to build up and level off be-hind the weir until steady-uniform ow is obtained.

When steady ow occurs over the weir, leakage isdetermined by direct reading from graduations onthe weir or converting the ow quantity to gallonsper unit length of pipe per unit of time.

An important factor in applying the test criteria isto properly account for the variable water head overthe length of sewer being tested. The downstreamend of the test section will often be subjected to agreater external water pressure than the upstreamend. To compensate for this variable external pres-sure, the test pressure should be that pressure cor-responding to the average head of water over thetest section. Certain test sections may exceed theallowable inltration, limits, but the average inltra-tion for the total project should be within the leak-age limits established for the particular project. Theeffect of increased depth of groundwater on inltra-tion allowances must be considered. An averagehead of 6 ft. (1.8 m) of groundwater over the pipe isestablished as the base head. With heads of morethan 6 ft. (1.8 m), the inltration limit is increasedby the ratio of the square root of the actual aver-age head to the square root of the base head. Forexample, with an average groundwater head of 12ft. (3.7 m), the 200 gallons per inch (18.5 liters permm) of diameter per 1.0 mile (1.67 km) of pipe perday inltration limit should be increased by the ratioor the square root of the actual average head, 12ft. (1.8 m), to the square root of the base head 6ft. (1.8 m), which results in an allowable inltrationlimit of 282 gallons per inch (26.2 liters per mm) ofdiameter per mile (km) of pipe per day.


55/90


EXFILTRATION

The exltration test is used in lieu of the inltra-tion test for small diameter sewers where individual

joints cannot be tested. Although actual inltrationwill normally be less than that indicated by the wa-ter exltration test, the test does provide a positivemethod of subjecting the completed sewer systemto an actual pressure test. Since sanitary sewersare not designed or expected to operate as a pres-

sure system, care must be exercised in conductingthe test and correlating the results with the allow-able exltration limits.

The test is usually conducted between adjacentmanholes in accordance with ASTM C 969M (C969). Prior to the test, all service laterals, stubs and

ttings within the test section should be plugged orcapped and adequately braced or blocked to with-stand the water pressure resulting from the test. Ifmanholes are to be included in the test, the inletpipe to each manhole should be bulkheaded and thetest section lled with water through the upstream

manholes. To allow air to escape from the sewer,the ow should be at a steady rate until the waterlevel in the upstream manholes is at the speciedlevel above the crown of the pipe. If necessary,provisions should be made to bleed off entrappedair during the lling of the test section. Once the

test section is lled the water should be allowed tostand for an adequate period of time to allow waterabsorption into the pipe and manhole. After wa-ter absorption has stabilized, the water level in theupstream manhole is brought up to the proper testlevel. This level is established by measuring down

from the manhole cover or other convenient datumpoint.After a set period of time, the water elevation


56/90


EXFILTRATION

TEST


57/90


should be measured from the same reference pointand the loss of water during the test period calculat-ed, or the water can be restored to the level existing

at the beginning of the test, and the amount addedused to determine the leakage.To exclude both manholes from the test, it is nec-

essary to bulkhead the outlet pipe of the upstreammanhole. Provisions must be made in the bulkheadfor lling the pipe and expelling trapped air.

ASTM C 969 (C 969M) recommends the waterlevel at the upstream manhole to be a minimum of2 ft. (600 mm) above existing groundwater, or 2 ft.(600 mm) above the crown of the upstream pipe,whichever is greater. Since a sewer is installed ona grade, the test section downstream will be sub-

jected to greater pressure. When the average headon the test section is greater than 3 ft. (900 mm),the allowable exltration limit should be adjustedin direct relationship to the ratio of the square rootof the average test head to the square root of thespecied base head, 3 ft. (900 mm).

The measured leakage of any individual sectiontested may exceed the leakage allowance speci-ed, provided the average of all sections testeddoes not exceed the specied leakage allowance.

AIRTESTING

The low-pressure air test conducted in accor-

dance with ASTM C 924 (C 924M) is a test, whichdetermines the rate at which air under pressure es-capes from an isolated section of sewer. The rateof air loss is intended to indicate the presence orabsence of pipe damage and whether or not the

joints have been properly constructed. The test is

not intended to indicate water leakage limits as nocorrelation has been found between air loss and


58/90


water leakage. The section of pipe to be tested isplugged at each end by means of inatable stop-pers. The ends of all laterals, stubs and ttings to

be included in the test should be plugged to preventair leakage, and securely braced to prevent pos-sible blowout due to internal air pressure. One ofthe plugs should have an inlet tap, or other provi-sion for connecting a hose to a portable air controlsource. The air equipment should consist of nec-essary values and pressure gauges to control therate at which air ows into the test section and toenable monitoring of the air pressure within the testsection.

Air is added to the test section until the internalair pressure is raised to a specied level and al-lowed to stabilize with the temperature of the pipewalls. The test is conducted by the pressure dropmethod, whereby, the air supply is disconnectedand the time required for the pressure to drop toa certain level is determined by means of a stop-watch. This time interval is then used to computethe rate of air loss. In applying low-pressure airtesting to sanitary sewers intended to carry uidunder gravity conditions, several important factorsshould be understood and precautions followedduring the test:

the air test is intended to detect defects in con-struction and pipe or joint damage and is notintended to be a measure of inltration or exl-tration leakage under service conditions, as nocorrelation has been found between air lossand water leakage.air test criteria are presently limited to concretepipe 24 in. (600 mm) in diameter and smallerby ASTM C924 (C 924M). Additional data isrequired to conrm the safety and applicability


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AIR

TEST


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or develop criteria for pipe larger than 24 in. indiameter.plugs should be securely braced to prevent the

unintentional release of a plug which can be-come a high velocity projectile. Plugs shouldnot be removed until all air pressure in the testsection has been released.for safety reasons, no one should be allowedin the trench or manhole while the test is beingconducted.the testing apparatus should be equipped witha pressure relief device to prevent the possibil-ity of loading the test section with the full com-pressor capacity

VACUUMTESTING

The vacuum (negative air pressure) test is gov-erned by ASTM C 1214 (C 1214M) for pipe and C1244 (C 1244M) for manholes. This test involvesremoving air from the pipe or manhole to a speciedpressure less than atmospheric. The ability to holda vacuum or a slow drop indicates an acceptable

pipe or manhole. This test is not quantitative butprovides economical testing of large samples. Oth-er benets include the inherent safety and economyof vacuum systems over pressurized systems.

This test method for pipe covers 4 to 36 in. (100mm to 900 mm) diameter circular concrete pipe

sewer lines utilizing gasketed joints and may beperformed in the eld or at the plant as a prelimi-nary test. The ends of all laterals, stubs, and t-tings should be plugged to prevent air leakage. Airis evacuated from the pipeline until a specied neg-ative air pressure is reached. The drop in vacuum

during the test period is recorded. The vacuum lossin cubic feet per minute (cubic meters per second)is calculated and compared to the allowable value.


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JOINTTESTING-AIR

Joint testing according to ASTM C 1103 (C1103M) may be performed on installed precast

concrete pipe sewer lines, using either air or waterunder low pressure to demonstrate the integrity ofthe joint and the construction procedures.

When using either air or water, the joint to betested is covered on the inside of the pipe by a ringwith two end element sealing tubes. Prior to this the

interior joint surface of the pipe should be cleanedand wetted. The joint test apparatus should beplaced inside the pipe with the end element sealingtubes straddling both sides of the joint. Inate endelement sealing tubes with air in accordance withequipment and manufacturers recommendations.

For the joint air test, the void volume should bepressurized to a specied pressure greater than thepressure exerted by groundwater above the pipe.Allow the air pressure and temperature to stabilize,then shut off the air supply and start testing. Thepressure should drop less than the allowable speci-

ed pressure drop. If the joint being tested fails, itmay be repaired and retested.

When performing the joint water test, the bleed-off petcock must be located at top dead center of thepipe. Introduce water into the void volume until thewater ows evenly from the open petcock. Close

the petcock and pressurize the void to a speciedpressure above the groundwater pressure. Shut offthe water supply. The pressure should drop lessthan the allowable specied pressure drop. If the

joint being tested fails, it may be repaired and re-tested.

JOINTTESTING-WATER

Conducting exltration tests on large pipe is usu-


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ally not practical because of the considerable quan-tity of water required. If the pipe is large enoughto be entered, each individual joint can be visually

inspected, and if necessary, subjected to a waterexltration test by means of test apparatus special-ly designed for this purpose. In this procedure, the

joint is isolated with an expanding shield equippedwith gaskets, which t tightly against the pipe wallson each side of the joint being tested. Throughappropriate piping, water is introduced into the an-nular space isolated by the shield and the leakagemeasured. The allowable leakage for individual

joints is that which would occur on the basis of theallowable water leakage for one pipe section.


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II.BOXCULVERTINSTALLATIONMANUAL

INTRODUCTION

With the development of national standards fordesign and manufacturing, box culverts are rapidlybecoming a large part of the precast industry. Oneof the unique benets of precast concrete boxesis their fast and easy installation, even under ad-verse eld and weather conditions. Precast boxes,

like concrete pipe, can be custom fabricated to anyconguration needed or desired in the eld. Wherelarger waterway capacity is required, multiple sec-tions can be placed side-by-side or connected inrows to provide an excellent storm water detentionsystem for areas with outfall ow restrictions or re-

quirements for on-site detention.This manual presents a guide for the properinstallation of concrete box culverts. While focus-ing on the construction of the box-soil system, thismanual also addresses those factors critical to thecompletion of the entire system, from delivery of the

box culverts to the jobsite, to the acceptance of theinstalled box line.This manual is intended as a guide and is not to

supersede the project specications.


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PRE-INSTALLATION

PRECAUTIONS

The Safety and Health Regulations for Construc-tion under the Department of Labor, OccupationalSafety and Health Administration (OSHA), arepublished federal regulations covering safety mea-sures for all types of construction, including sewerand box culvert installations. All prime contractors

and subcontractors are subject to these regulationswhen involved in any type of construction, includ-ing alterations and repair work. Installers should beaware of these regulations.

Reviewing proper installation practices, whileconsidering the engineers design assumptions (in

relation to the use of trench boxes and backll com-paction requirements) will help to ensure workersafety as well as culvert longevity.

ORDERING,RECEIVING&HANDLING

Although the contractor is ordering the product,both the engineer and the supplier should be aware

of the proposed schedule of the contractor. Coordi-nation between the three parties will prevent unnec-essary delays. Much of the time the manufacturerstocks a wide range of box sizes for varied depths,however, manufacturing facilities must frequentlyadapt to meet job requirements. Therefore, for spe-

cial box types and large orders, prior knowledge willassist in correct and on-time delivery. When order-ing box culverts, specications should be in writingand should include:

Specication designationName and location of project

Box size, laying length and the bury depthTotal footage of each type and size of box


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Design live loadType of jointList of ttings

Material test requirementsJoint material and quantityInvoicing instructions

The following information should be clearlymarked on each box section:

Specication designationMinimum and maximum bury depthSpan, rise, table number, top of box and de-sign earth cover for ASTM C 1433 (Standard),C 1577 (LRFD)Date of manufactureName or trademark of the manufacturer

SCHEDULING/UNLOADING/PLACING/SEQUENCE

It is important to be prepared for the delivery ofevery box. The proper machinery should be avail-able to handle the unloading and placing of eachsection. Each shipment is tied down to avoid dam-

age during transport. However, it is the responsi-bility of the contractor to make certain no damagehas occurred during transit. An overall inspectionshould be performed upon arrival of the boxes. Be-fore unloading, the delivered box should be checkedagainst the order invoice to ensure accurate deliv-

ery of all items.If a box has been damaged it should be set

aside and recorded to ensure its proper order inthe installation sequence. In some cases damagedends, chips and cracks, which do not pass throughthe wall, can be repaired on site, while others are

irreparable and may have to be returned to the sup-plier for replacement.


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When unloading boxes, caution should be ex-ercised to ensure no personnel are in the path ofthe box as it is being moved. The box should be

handled per manufacturers recommendations.Use only manufacturer approved lifting devices tohandle box culvert sections. The box should be lift-ed and never dragged to avoid damage. If the liftingdevice could chip the box, padding should be pro-vided between the box and the lifting mechanism.

When a box is provided with lifting holes, the lift-ing device should pass through the wall and distrib-ute the weight along the inside wall of the box.

If the box is going to be installed directly from thetruck trailer to the nal location, a crane with stabi-lizers should be used. Be aware that some crawlerswithout outriggers, or backhoes, may not have thestability or maneuverability needed to line up theunits for proper installation.

If the box is going to be stored on-site, alterna-tive means can be used to transport the sections totheir temporary location. Care must be taken at alltimes and handling of boxes should be limited. Themanufacturers handling recommendations shouldbe followed at all times. Mishandling can result incracked bells and spigots.

Special boxes are normally shipped in the orderthey should be installed and therefore should bestored in the order of delivery.

STORING

Storing of boxes should be done as near to thenal installation destination as possible. If stackingof boxes is advisable, a at surface with no rocksshould be chosen for the rst layer. Follow the

manufacturers recommendations for an accept-able stack height.


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Gaskets and sealing materials should be storedin a cool dry place until needed. Rubber gasketsand bulk mastic or preformed mastics should be

kept clean and away from excessive heat. Somemastics may need to be heated under extreme coldconditions, and tar joint compound should also beheated for optimum behavior during application.


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SITEPREPARATION

EXCAVATION

Trenches should be excavated to the dimensionsand grade specied on the plans or as ordered bythe owner. The width of the trenches should be keptto the minimum required for installation of the boxsections (ASCE 26-97). The trench width shouldtake into account the machinery needed to prop-

erly install the box section. Over excavated areasshould be backlled with approved materials andcompacted to the Standard Proctor density speci-ed for the leveling course.

Preparation of the site should establish a goodlevel grade, using ne to medium granular mate-

rial. When ledge rock, compacted rocky, or otherunyielding foundation material is encountered, itshould be removed to the requirements shown onthe plans. The foundation should be moderatelyrm to hard in-situ soil, stabilized soil or compactedll material. If unstable or unsuitable material is en-

countered, it should be removed and replaced withstable material approved by the engineer.Stockpiling excavated material adjacent to the

trench could cause a surcharge load, which maycave-in the trench walls. The ability of the trenchwalls to stand vertically under this additional loaddepends on the cohesive characteristics of the par-ticular type of material being excavated. This sur-charge load should be considered when evaluat-ing the need to provide trench support. It may benecessary where deep or wide trenches are beingexcavated to haul away a portion of the excavatedsoil or spread the stockpile with a bulldozer or otherequipment. If the excavated material is to be usedas backll, the stockpiled material should be visu-


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ally inspected for rocks, frozen lumps, highly plasticclay or other objectionable material. If the excavat-ed soil differs signicantly from the intended backll

material set forth in the plans, it may be necessaryto haul the unsuitable soil away and bring in selectbackll material.

TRENCHWATER

In the case where the water table is located inthe trench zone, dewatering methods must be em-

ployed to remove the water. The future location ofthe water table must also be considered due to itseffect on backll material and the box section. Thepresence of water around the box could cause o-tation of the box section, or migration of the backllmaterial. Migration of soil should be prevented, as

the backll is a means of support for the box.There are different methods that can be used to

remove this water: pumping, ditching, and/or pipingof the water. It should be noted that all pumpingshould be through a ltered discharge.

BEDDING/GRADEPrecast reinforced concrete box sections are de-

signed for installed conditions rather than test con-ditions. Designs are presented in ASTM StandardsC 1433(M) and C 1577(M), and AASHTO M 259(M)and M 273(M). Beddin

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