Document 5bGDYNdKB76oLD29eQKbwa4ZN

American Water Wbrks Association AWWA C301-72 Revision of AWWA C301-64 AWWA STANDARD lot PRESTRESSED CONCRETE PRESSURE PIPE, STEEL CYLINDER TYPE, FOR WATER AND OTHER LIQUIDS First edition approved by Board of Directors Nov. 21, 1949. This edition approved Jan. 31, 1972. AMERICAN WATER WORKS ASSOCIATION 6666 West Quincy Avenue, Denver, Colorado 80235 CTD014670 Committee Personnel Three subcommittees were instrumental in the revision of this standard. ) Subcommittee on Revision of AWWA C301 T. C. Earl, Chairman J. F. WlCKSER R. E. Bald W. R. Dana S. B. Maynard Subcommittee on Design Appendices E. L. Wright, Chairman R. A. Skinner C. E. Beal W. Brunzell L. R. Keyser Subcommittee on Standardization of Format and Terminology L. H. Burton, Chairman R. T. Tillotson C. A. Parthum C. B. Clincer J. A. Willett The Standards Committee on Concrete Pressure Pipe, which reviewed and 3approved this standard, had the following membership at the time of approval- M. E. Barber C. E. Beal W. Brunzell T. C. Earl J. L. Geren J. O. Ghimsley User/Gcneral Interest Members W. K. Neubauer, Chairman R. E. Morris Jr., Vice-Chairman S. B. Maynard A. C. Michael H. F. Peckworth A. E. Scalzitti R. A. Skinner R. T. Tillotson P. M. Walker J. F. WlCKSER E. W. Whitlock S. E. Dore Jr. (NEWWA Rep.) S. M. Dore (NEWWA Alternate) C. A. Parthum (NEWWA Alternate) R. E. Bald J. H. Bailey Producer Members W. R. Dana L. R. Keyser J. A. Willett E. L. Wright Copyright 1972 by the American Water Works Assn., Inc. Printed in USA CTD014671 Approved by the AWWA Board of Directors. fan. 28. 1974 Addenda to AWWA Standard Preetressed Concrete Pressure Pipe. Steel Cylinder Type, for Water and Other Liquids and AWWA Standard for Reinforced Concrete Water Pipe--Steel Cylinder Type, Pretensioned AWWA C301a-74 Supplement to C301-72 and AWWA C303a-74 Supplement to C303-70 American Water Works Association Copyright 1974 by the American Water Works Association, 6666 West Quincy Avenue, Denver, Colo. 80235. Printed in the US. Add the following to C301, paragraph 2.7.1: Steel sheets or coils conforming to the requirements of "Specifications for Steel, Cold-Rolled Sheet, Carbon, Structural" (ASTM Designation A611), Grade B, C or E, may also be utilized for pipe cylinders. Add the following to C303, paragraph 2.5.1 : Steel sheets or coils conforming to the requirements of "Specifications for Steel, Cold-Rolled Sheet, Carbon, Structural" (ASTM Designation A611), Grade B or C may also be utilized for pipe cylinders. m CTD014672 Table oi Contents SEC. Foreword PACE ....................... V Information Recar'lmg l_ -e of This Standard ...................... vi [ General ................................................ 111i...41l; PDElseabsnfviesnniPttiiauoanrlncd*hRaeDs.qae.utr.iar.e..m.T...eo..n..t..Bs..e........F...u...r...n...i.s...h...e.....d 1.5 Data To Be Submitted b\' Manu- facturer ....................... 1.6 Marking ........................ 1.7 Inspection and Testing bv Pur- chaser ....................... 111...9810 TAMefafsitdtesariva.itl..oa.nf.d.C.o.W.m.op.rl.kia.m.na.c.en.s.h..i..p................... 2 2.1 22 22..34 CFMienameteeAnritaglg.rS.e.pg.ea.c.tie.fi..c..a..t.i.o..n...s...................... Coarse Aggregate ...... ........ Samples of Aggregates ......:... 2.5 Water .......................... 22..67 AStdemelixftourreCsylin..d.e.r.s..a.n.d..F..it.t.in.g..s..... iii> 2 33 445 56666557 SEC. PAGE 2.3 222...19110 RSSStttueeeMbeeebelll sefChrfooarfrsRotJreinoWignGinsfiaortserfcko,ReeritmnsBgFeasni.rt.t,ti..n...ga...ns...d...........W........i..r..e....- 887/ 33333....1234 337.63 Design and Fabrication of Pipe .. General Requirements ........... JDRFoaeuibsbnibrtgiecnRratoiGinofgansPsoikpfe.e.tSs..t..e...e...l......C...v...l...in.....d....e...r...s................ Concrete for Pipe Core.......... 33..78 CPluarcininggooff CWoriere .R..e.in..fo.r.c.e.m..e.n.t...... 33..190 CPiupreingCooaftiCngoa.ti.n.g............................... 3.11 Seal Coat ...................... 999 111111111515143400 444444...42153 Fittings and Special Pipe.............. GFFiiettttniinnerggassl ((.TT.vv.pp..ee..AB.).)............................................ COuprevneisn,gsBeanndds,CaonndneCclotsiounress............ 111111566556 17Appendices ....................................... A Cubic Parabola Design Method ... 17 B Stress 18Analysis Design Method ... IV CTD014673 Foreword This foreword is for information only and is not part of AWWA C301-72 History oi Standard Prestressed-concrete steel-cylinder pipe, as described in this standard, pro vides an optimum utilization of steel and concrete with minimal weight un der given design conditions and gives excellent performance under various internal and external pressure condi tions. There are two types of prestressedconcrete steel-cylinder pipe: (1) the lined-cylinder type with a core com posed of a steel cylinder lined with con crete and subsequently wire-wrapped directly on the steel cylinder and coated with mortar; and (2) the embeddedcylinder type with a core composed of a steel cylinder encased in concrete and subsequently wire-wrapped on the ex terior concrete surface and coated with concrete or mortar. The lined-cylin der type, which was first used in the US in 1942, is furnished in sizes from 16 to 48 in. The embedded-cylinder type, which was developed later and first installed in 1953, is manufactured in sizes 24 in. and larger. Both types are designed for the spe cific combination of internal pressure and external load required for the proj ect in accordance with the procedures outlined in the appendices of this standard. Lined-cylinder type is de signed generally for pressures up to 250 psi and embedded-cylinder type, up to 350 psi, but both types have been designed and constructed for substan tially higher pressures. Prestressed-concrete steel-cylinder pipe is used for transmission mains, distribution feeder mains, pressure si phons (including river crossings), penstocks, industrial pressure lines, water intake lines, sewer force mains, and sewer outfall lines. In the manufacture of lined-cyjinder pipe, the first step is to make and hy draulically test the steel cylinder with joint rings attached. The cylinder is then centrifugally lined with dense con crete to constitute the core. The con crete lining is cured and high-tensile wire is wrapped around the core di rectly on the steel cylinder. For a se lected wire size, the tension and spacing of the wire are controlled to produce a predetermined residual compression in the core to meet design requirements. The wrapped core is then covered with a dense premixed mortar coating about | in. thick, applied by a mechanical im pact method. In the manufacture of embeddedcylinder pipe, the cylinder and joint rings are constructed and tested in the same manner as for lined-cylinder pipe. The cylinder is encased in concrete by vertical casting and mechanical vibra tion to constitute the core. After cur ing, the wire reinforcement is wound, under tension, in one or more layers around the outside of the concrete core containing the cylinder, instead of di rectly on the cylinder. The exterior coating of premixed mortar or concrete is placed by an impact method or by vertical casting. Embedded-cylinder construction has been found to be su perior for large sizes and for pipe de signed for comparatively high pressures. v CTD014674 vi AWWA STANDARD The first edition of this standard was approved as "Tentative" on Nov. 21, 1949. It was revised and made "Standard" on Jun. 13, 1952. The second edition was approved as "Tenta tive" on Jun. 17, 1955, and made "Standard" on Jun. 26, 1958. Sub stantial changes, including the addition of combined loading procedures, were included in the third edition, which was made "Standard" as of Jan. 27, 1964. Installation of this pipe is covered by AWWA Manual M-9, Installation of Concrete Pipe. Information Regarding Use of This Standard When purchasing pipe under the provisions of this standard, the pur chaser shall furnish supplementary specifications to include specific details concerning the following: 1. Standard used; that is, AWWA C301-72 2. Type of pipe, either lined-cylinder pipe or embedded-cylinder pipe (Sec. 1.3) 3. Manner of storage and delivery, if required of the manufacturer 4. Whether there is any internal op erating pressure, transient pressure, ex ternal earth load, or trench bedding condition in excess of that provided for in Sec. 3.2 (Sec. 1.2.8, 1.2.9, 1.4.1, and 1.5.2) 5. Whether pipe may not be sup plied from inventory (Sec. 1.5.1) 6. Whether a tabulated layout sched ule (Sec. 1.5.2) will be required 7. Identification marks required (Sec. 1.6) 8. Whether the purchaser desires to inspect the pipe and fittings at the manufacturer's plant (Sec. 1.7.1) 9. Whether steel test reports (Sec. 1.9.3) and test specimens (Sec. 1.9.4) will be required 10. Whether submission of rubber gasket material test reports (Sec. 1.9.5 and 2.11.8) will be required 11. Whether an affidavit of compli ance (Sec. 1.10) will be required 12. Type of cement required, if there is a preference (Sec. 2.1.1) 13. Whether aggregate samples (Sec. 2.4) will be required 14. Whether submission of manufac turer's design calculations (Sec. 3.2.1) will be required 15. Type of protective coating on ex posed portions of joint rings (Sec. 3.3) 16. Whether submission for approval of details of materials and methods of welding (Sec. 3.5.2) will be required 17. Whether a specific seal coat (Sec. 3.11) will be required 18. Details of fittings (Sec. 4.1) 19. Testing of steel cylinders for fittings (Sec. 4.2 and 4.3) 20. Whether lining and coating of structural-steel connections (Sec. 4.5) will be required Major Revisions The major revisions in this edition consist of the following: 1. The title has been changed to re flect the scope of the standard more accurately. The phrase "water pipe" has been changed to "pressure pipe" and the following phrase was added: "For water and other liquids" 2. The entire standard was carefully reviewed and changes were made in most of the sections to improve under standing and readability 3. Use of the standard was improved by the addition of titles to all sections I CTD014675 PRESTRESSED CONCRETE PRESSURE PIPE Vll 4. The scope, which formerly pro vided for pipe sizes from 16 in. to 96 in., was enlarged to provide for sizes from 16 to 144 in. 5. A minimum cylinder thickness of 18 gage is permitted for pipe 48 in. and smaller; and of 16 gage for pipe 54 in. and larger 6. Provision has been made that the minimum design thickness of the core, including the thickness of the cylinder, shall be iV of the design pipe diameter. This provision eliminates the need for Table 3 in the previous edition of AWWA C301. In that table the core thickness for embedded-cylinder pipe larger than 48 in. in diameter was based, for manufacturing reasons, on using the outside form for AWWA C300 pipe of the same diameter to cast the concrete embedment over the steel cylinder. 7. Multiple layers of circumferential reinforcement are expressly provided for in Sec. 3.8. This is necessary when high pressures are involved and the re quired amount of wire cannot be fur nished in one layer because of insuffi cient space 8. The requirements for "ordinary'1 bedding, as specified in Sec. 3.2.2, have been provided. The previous edition specified "ordinary" bedding, but did not define the requirements 9. The extra circumferential wrap of wire required at each end of the core may now be applied at one half the design tension. This will most benefit embedded pipe where the wire anchor age has usually been embedded in the concrete and, at times, has pulled loose at the beginning of the wrapping process 10. The minimum time required for steam curing has been reduced from 32 to 24 hr. The actual time used will depend on temperature, which may vary from 110F to 150F, and other conditions. This does not relax the concrete strength requirements. The wrapping with high-tensile wire cannot begin until the concrete has reached minimum specified seven-day compres sive strength and the initial compres sion in the concrete shall not exceed 55 per cent of the compressive strength of the concrete at the time of wrapping. CTD014676 % Amefcan Water v\torks Association AWWA C301-72 Revision of AWWA C301-64 AWWA Standard for Prestressed Concrete Pressure Pipe, Steel Cylinder Type, lor Water and Other Liquids Section 1--General Sec. 1.1--Scope This standard covers the manufac ture of circumferentially prestressed concrete water pipe with a steel cylin der and wire reinforcement in sizes from 16 to 144 in., inclusive. The standard covers two types of pre stressed pipe: (1) lined-cylinder pipe with a core composed of a steel cylinder lined with concrete and subsequently wire-wrapped and coated with pre mixed mortar; and (2) embeddedcylinder pipe with a core in which a steel cylinder is encased in concrete and subsequently wire-wrapped and coated with premixed concrete or mortar. This standard does not include require ments for handling, delivery, laying, field testing, or disinfection of the pipe. Sec. 1.2--Definitions In this standard the following defi nitions shall apply: 1.2.1--Purchaser. The word "pur chaser" shall mean a person, firm, cor poration, or government subdivision entering into a contract or agreement to purchase pipe and fittings according to this standard. 1.2.2-- Contractor. The word "con tractor" shall mean the person, firm, or corporation executing the contract or agreement with the purchaser to furnish pipe and fittings according to this standard. 1.2.3--Manufacturer. The word "manufacturer" shall mean the person, firm, or corporation who actually man ufactures the pipe, acting either di rectly as the contractor or as a sub contractor or supplier. If the manu facturer is acting as a subcontractor under the contractor or otherwise as a supplier to the contractor, the obliga tions of the manufacturer under this standard shall be considered as obliga tions of the contractor, and the con tractor shall be responsible for their performance. 1.2.4-- .ASTM. The term "ASTM" shall mean the American Society for Testing and Materials. When specific ASTM specifications are cited without QTD0U677 1 AWWA STANDARD dates, the designation shall be con Sec. 1.3--Essential Requirements strued to refer to the latest revision under the same specification number, or to superseding specifications under a new number, except for provisions in the revised specifications that clearly are inapplicable. 1.2.5-- ANSI. The term "ANSI" shall mean the American National Standards Institute. 1.2.6--Approved. The term "ap proved" shall mean having received the approval of the purchaser. The pipe shall have the following principal features: a welded steel cyl inder with steel joint rings welded to its ends; for lined-cylinder pipe, a core consisting of a lining of concrete within the steel cylinder, or for embeddedcylinder pipe, a core consisting of the steel cylinder encased in concrete; re inforcement consisting of high-tensile wire wound around the outside of the core in one or more layers at a pre determined stress and securely fastened 1.2.7-- Design pressure. The design at its ends; a coating of dense mortar pressure shall be the maximum sus or concrete covering the core and wire, tained internal hydrostatic pressure to except for the necessarily exposed sur which the pipe is to be subjected. Gen faces of the joint rings ; a self-centering erally, the design pressure for each joint with a preformed gasket of rub pipe, or portion of the pipeline, shall be ber, so designed that the joint will be the operating pressure established by watertight under all conditions of serv the hydraulic gradient or the static ice. Lined-cylinder pipe shall be used head specified by the purchaser, which for pipe sizes up to and including 20 ever results in the greater pressure. in. and may be used for pipe sizes up 1.2.8-- Surge pressures. Surge pres to and including 48 in. Embedded- sures are internal pressure overloads cylinder pipe may be used for pipe of relatively short duration. sizes 24--48 in. and shall be used for 1.2.9-- External loads. The term larger pipe. For embedded-cylinder "external loads" shall mean all super pipe, at least one third of the total core imposed live and dead loads applied thickness shall be outside the cylinder. to the outside of the pipe after installa tion. Sec. 1.4--Plans and Data To Be 1.2.10-- Normal operating conditions. Furnished by Purchaser Normal operating conditions are de fined as a combination of design pres sure and external dead loads. 1.4.1--Design data. The purchaser shall designate the design pressure for which the pipe shall be manufactured. 1.2.11-- Transient conditions. Tran If the pipe is to be used under condi sient conditions are conditions due to tions where the external loads or surge surge pressures or live loads that ex pressure will be in excess of that stated ceed normal operating conditions and in Sec. 3.2 as provided for in the nor are of short duration. mal design of the pipe, the purchaser 1.2.12-- Pipe diameter. The term shall designate the external load or "pipe diameter" or "size" shall mean surge-pressure conditions for which the the design inside (waterway) diameter pipe shall be designed. For external of the pipe. loads in excess of those provided for in 1 * t t CTDO14678 PRESTRESSED CONCRETE PRESSURE PIPE 3 Sec. 3.2, a statement or detail of bed ding and backfilling procedures shall be included. 1.4.2--Plans. At least 1 month prior to manufacture, the purchaser shall fur nish the contractor with plans and pro files showing: alignment and grades; location of all outlets, connections, and special appurtenances; design pressures for each part of the line; and such spe cial details or information as are neces sary for the manufacture of the pipe and fittings in accordance with this standard and with the specific require ments of the work for which the pipe is made. Sec. 1.5--Data To Be Submitted by Manufacturer 1.5.1-- Detail drawings and sched ules. The manufacturer shall submit, for approval by the purchaser, draw ings and schedules showing full details of reinforcement, concrete, and joint dimensions for the pipe and fittings. All pipe and fittings shall be fabricated in accordance with these approved drawings and schedules. Pipe may be supplied from inventory unless the pur chaser has indicated otherwise. 1.5.2-- Tabulated layout schedule. When specifically required, the data submitted by the manufacturer shall include a tabulated layout schedule, with reference to the stationing and grade line shown on the drawings sup plied by the purchaser. The schedule shall show pressure zones, each of which shall be designated by the de sign pressure and transient pressure applicable therein, and the point of change from one zone to the next shall be clearly indicated by station number. The diameter of the pipe, the design pressure and transient pressure, and the thickness of pipe wall and area of steel (per linear foot of pipe) in the reinforcing wire and steel cylinder shall be listed for each portion of pipeline. Sec. 1.6--Marking Each length of straight and special pipe and each fitting shall have plainly marked inside, on the bell or spigot end, the identification marks specified by the purchaser. These shall include, as specified, either the pressure for which the pipe or fitting is designed or the area of effective circumferential re inforcement per foot of pipe wall. Special marks of identification, suffi cient to show the proper location of the pipe or fitting in the line by reference to layout drawings and schedules speci fied under Sec. 1.5, shall be placed on the pipe if specifically required. All beveled pipe shall be marked with the amount of the bevel, and the point of maximum pipe length shall be marked on the beveled end. Sec. 1.7--Inspection and Testing by Purchaser 1.7.1-- Inspection at manufacturer's plant. If the purchaser desires to in spect pipe and fittings at the manufac turer's plant, he shall so specify in the contract or agreement, stating the con ditions (such as time, and the extent of inspection) under which the inspec tion shall be made. 1.7.2-- Access to work. The pur chaser shall have free access to those parts of the manufacturer's plant that are necessary to assure compliance with this standard. The manufacturer shall make available for the purchaser's use such gages as are necessary for inspec tion. The manufacturer shall provide the purchaser with assistance as neces- CtD014679 4 AWWA STANDARD sary for the handling of pipe and fit specified. All work shall be done in tings. a thorough, workmanlike manner by 1.7.3-- Responsibility. Inspection by mechanics skilled in their various the purchaser, or failure of the pur trades. When a lower limit or mini chaser to provide inspection, shall not mum dimension is given herein for a relieve the contractor of his responsi steel component, the minus tolerance bility to furnish materials and to per (as stated in the applicable ASTM form work in accordance with this specification) for such limit or dimen standard. sion shall be understood to define the 1.7.4-- Tests. Tests under Sec. 1.9, true lower limit or dimension. made by the purchaser on material samples, shall be carried out without Sec. 1.9--Tests delay. If any sample fails to meet the requirements, the manufacturer shall be notified immediately. Material af fected by the test results shall be set aside pending final disposition. The manufacturer may request a review of test procedures, and additional tests on the material. Duplicate samples, the number of which is to be agreed upon, should be tested by the pur chaser and by the manufacturer. The manufacturer's tests shall be performed by a commercial testing laboratory or in the manufacturer's laboratory, with proper certification. Tests by either party may be witnessed by the other. If the duplicate samples meet the test requirements, the material shall be ac cepted. If the material is rejected after retesting, the manufacturer shall pay all costs of retesting. 1.7.5--Rejection. Material, fabri 1.9.1-- Cylinder assembly. Each completed cylinder with joint rings welded to its ends shall be subjected to a hydrostatic test as specified herein under Sec. 3.5.3. 1.9.2-- Concrete. Samples of the mixed concrete shall be taken for mak ing compression test cylinders as spe cified under Sec. 3.6.5 and 3.6 6. 1.9.3-- Steel reports. Mill test re ports or plant test reports on each heat from which the steel is rolled shall be obtained by the manufacturer and made available to the purchaser on request. 1.9.4-- Steel specimens. The manu facturer shall provide test specimens, cut from each shipment of steel for cylinders and high-tensile wire, if re quired by the purchaser. 1.9.5-- Gasket rubber. Test reports showing the physical properties of rub cated parts, and pipe that are discov ber used in the gaskets, as specified in ered to be defective, or that do not con form to the requirements of this stand ard, will be subject to rejection at any time prior to final acceptance of the pipe. Rejected material and pipe shall be removed promptly from the site of the work. Sec. 1.8--Material and Workmanship Sec. 2.11.8, shall be obtained by the manufacturer and shall be made avail able to the purchaser on request. 1.9.6-- Expense. The expense of testing the materials and of submitting to the purchaser test reports in accord ance with this standard and the pur chaser's supplementary specifications All material furnished by the manu referred to in the foreword, and the facturer shall be new and of the quality expense of testing the completed steel 1 > I CTD014680 PRESTRESSED CONCRETE PRESSURE PIPE s cylinder in accordance with Sec. 1.9.1 and of testing concrete in accordance with Sec. 1.9.2, shall be borne by the manufacturer. All other tests shall be made by the purchaser at the pur chaser's expense, except as otherwise specifically provided. Sec. 1.10--Affidavit of Compliance The purchaser may require an affi davit from the manufacturer that the pipe and fittings furnished under the purchaser's contract or agreement com ply with all applicable provisions of this standard. Section 2--Material Specifications Sec. 2.1--Cement clean, hard, durable, and uncoated par 2.1.1-- Type. Cement for concrete ticles of natural sand or of sand pre work shall conform to the "Specifica pared from the product obtained by tions for Portland Cement" (ASTM crushing stone or gravel. At the time Designation Cl50). Either Type I of use the fine aggregate shall be en or Type II may be used unless the tirely free of frozen material. purchaser specifies a particular type. 2.2.2--Gradation. Fine aggregate Sampling and testing shall conform to shall be well graded from coarse to the individual ASTM specifications fine and, when tested by means of lab designated therein. oratory sieves in accordance with the 2.1.2-- Inspection. Satisfactory fa "Method of Test for Sieve or Screen cilities shall be provided for identify Analysis of Fine and Coarse Aggre ing, inspecting, and sampling cement at gates" (ASTM Designation C136), the mill, the warehouse, and the site of shall conform to the gradation require the work. The purchaser shall have ments in Table 1. the right to inspect the cement and ob tain samples for testing at any of these points. TABLE 1 Gradation Requirements for Fine Aggregate 2.1.3-- Storage. Cement shall be stored in a weathertight, dry, wellventilated structure. 2.1.4-- Unusable. Cement salvaged Sieve Size byTotal Parsing. Weight. % Concrete Sand Mortar Coating Sand by cleaning cement sacks, mechanically or otherwise, shall not be used in the work. Cement containing lumps shall be rejected and shall immediately be removed from the site of the work. 2.1.5-- Temperature. If the tem perature of the cement exceeds 150F, lMMooin... 48 MMoo.. 3106 MMMooo... 25100000 951-01000 642550---987800 5-50 0-52-10 100 100 70-9093-100 45-65 132--1325 0-5 it shall be stored until cooled to that temperature. Sec. 2.2--Fine Aggregate These gradation requirements repre sent the extreme limits for determining 2.2.1--General. Fine aggregate for the suitability of fine aggregate under concrete and mortar shall consist of this standard. To maintain uniformity CTD014681 6 AWWA STANDARD of gradation for aggregate from any given source, a fineness modulus de termination shall be made upon repre sentative samples from that source. Thereafter the fineness modulus of all shipments therefrom shall not vary more than 0.20 from the fineness modulus of the representative sample, unless suitable approved mix adjust ments are made. 2.2.3--Impurities. Fine aggregate shall be free from injurious amounts of organic impurities and shall conform to Sec. 4.2 of "Specifications for Con crete Aggregates'' (ASTM Designation JC33-71a). Sec. 2.3--Coarse Aggregate TABLE 2 Permissible Amounts of Deleterious Substances in Coarse Aggregate Materia] Soft particles Coal and lignite Clay lumps Material finer than 200 sieve Combined total of above items Maximum Weight Limit, % 5.00 0.50 0.25 1.00 5.00 exceed the amounts given in Table 2, as determined by sampling and testing procedures listed in the "Specifications for Concrete Aggregates" (ASTM Designation C33). 2.3.1-- General. Coarse aggregate for concrete shall consist of hard, dur able particles of crushed stone or crushed or uncrushed gravel, conform ing to the requirements and tests given in Sec. 2.3.2 through 2.3.3. 2.3.2-- Gradation. Coarse aggregate shall be well graded from coarse to fine. The maximum size and gradation shall be subject to the approval of the purchaser and shall be such that the concrete can be readily placed in the core or poured coating, by the particu lar method used in placing it, to pro vide a solid, compact, homogeneous wall with a smooth surface. Tests for gradation of coarse aggregate shall be in accordance with the "Method of Test for Sieve or Screen Analysis of Fine and Coarse Aggregates" (ASTM Designation Cl36). Thin and elon gated pieces, the maximum dimension of which exceeds five times the mini mum, shall not be in excess of 10 per cent of the coarse aggregate by weight. 2.3.3-- Impurities. Deleterious sub stances in coarse aggregate shall not Sec. 2.4--Samples of Aggregates At least 4 weeks prior to mixing con crete, the manufacturer, if required, shall provide in suitable containers, for preliminary approval, samples of not A less than 1 cu ft each of fine and TM coarse aggregate. All samples shall be plainly labeled to indicate the source of the material, the date, and the name of the collector. Methods of sampling aggregates shall be in accordance with the "Methods of Sampling Stone, Slag, f Gravel, Sand, and Stone Block for Use as Highway Materials" (ASTM Desig nation D7S). Sec. 2.5--Water Water used for concrete and for cur ing pipe shall be fresh water and shall be clean and free from oil, acid, strong alkalies, or vegetable matter. Sec. 2.6--Admixtures At the option of the manufacturer, the concrete may contain a water-re ducing, set-controlling admixture con forming to the "Specification for Chem- ^ CTD014682 PRESTRESSED CONCRETE PRESSURE PIPE 7 a ical Admixtures for Concrete" (ASTM tings shall conform to the "Specifica TM Designation C494). No admixture tions for Welded Steel Wire Fabric for ^ shall contain calcium chloride. The Concrete Reinforcement" (ASTM ' type and amount of admixture shall be Designation A185). subject to the purchaser's approval. 2.8.3--Bars. Steel-bar reinforce Sec. 2.7--Steel for Cylinders and Fittings ment for concrete for fittings shall con form to "Specifications for Carbon Steel Bars Subject to Mechanical 2.7.1--Steel sheets. Steel sheets for pipe cylinders and fittings may be in cut lengths or coils and shall, meet the requirements of the "Specification for Hot-Rolled Carbon Steel Sheets and Strip, Structural Quality" (ASTM Designation AS70), Grade B or C, or "Specifications for Hot-Rolled Car bon Steel Sheets and Strip, Commercial Quality" (ASTM Designation A569), except that for ASTM A569 steel, the maximum carbon content may be 0.2S per cent and the minimum yield point Property Requirements" (ASTM Des ignation A306), Grade 80, or to "Speci fications for Deformed Billet-Steel Bars for Concrete Reinforcement" (ASTM Designation A615-68), Grade 40, ex cept that for plain bars supplied under ASTM A615-68, (1) the requirements of Sec. 6, 7, and 14.3 shall not apply; (2) intermediate bar diameters shall meet the requirements of the next smaller bar number designation; and (3) bar diameters less than No. 3 shall meet the requirements for No. 3 bar. 0- shall be 27,000 psi. 2.7.2--Steel plates. Steel plates for Sec. 2.9--Steel for Joint Rings pipe cylinders and fittings shall con Steel for bell rings less than J in. form to "Specifications for Low and thick shall conform to "Specifications Intermediate Tensile Strength Carbon for Hot-Rolled Carbon Steel Sheets Steel Plates of Structural Quality" and Strip, Structural Quality" (ASTM (ASTM Designation A283), Grade B Designation A570), Grade A, or to or C. "Specifications for Hot-Rolled Carbon 0 Sec. 2.8--Steel for Wire, Bar and Wire-Mesh Reinforcement Steel Sheets and Strip, Commercial Quality" (ASTM Designation A569). Special shapes for spigot joint rings 2.8.1--Prestressing wire. The wire and steel for bell rings $ in. or more for circumferential reinforcement shall conform to "Specifications lor Steel Wire, Hard-Drawn for Mechanical Springs" (ASTM Designation A227). Wire with specified minimum tensile strengths exceeding those in A227, Class II, may be used if the wire meets the other requirements for Class II in in thickness shall conform to "Specifi cations For Carbon Steel Bars Subject to Mechanical Property Requirements" (ASTM Designation A306), Grade 50, or to "Specifications for Low and In termediate Tensile Strength Carbon Steel Plates of Structural Quality" (ASTM Designation A283), Grade A, or to "Specifications for Merchant that specification, and the pipe design Quality Hot-Rolled Carbon Steel Bars" may be based on these higher strengths. (ASTM Designation A575), Grade 2.8.2-- IVire mesh. Wire-mesh re- 1012, or to "Specifications for Special * inforcement for mortar coating for fit Quality Hot-Rolled Carbon Steel Bars" CTD014683 8 AWWA STANDARD (ASTM Designation A576), Grade 1012, or to "Specifications for Steel' Sheet and Strip, Carbon, Hot-Rolled Commerical Quality, Heavy-Thickness Coils (Formerly Plate)" (ASTM Des ignation A635). Sec. 2.10--Steel Castings for Fittings Steel castings for fittings shall con form to the "Specifications for Mild to Medium Strength Carbon Steel Cast ings for General Application" (ASTM Designation A27), Grade 70-36, nor malized. Sec. 2.11--Rubber for Gaskets 2.11.1-- General. The gasket shall have smooth surfaces free from pitting, blisters, porosity, and other imperfec tions. The rubber compound shall con tain not less than 50 per cent by volume of first-grade natural crude or firstgrade synthetic rubber. The re mainder of the compound shall consist of pulverized fillers free from rubber substitutes, reclaimed rubber, and dele terious substances. The compound shall meet the following physical re quirements when tested in accordance with the indicated conditions and desig nated ASTM test methods. 2.11.2-- Tensile strength. The ten sile strength of the compound shall be at least 2,700 psi for natural rubber gaskets and 2,000 psi for synthetic rub ber gaskets--"Method of Tension Test ing of Vulcanized Rubber" (ASTM Designation D412). 2.11.3-- Elongation at rupture. The elongation at rupture shall be at least 400 per cent for natural rubber gaskets and 350 per cent for synthetic rubber gaskets--"Method of Tension Testing of Vulcanized Rubber" (ASTM Desig nation D412). 2.11.4-- Specific gravity. The spe cific gravity shall not vary more than 0.05 within the range 0.95-1.45-- "Methods for Chemical Analysis of Rubber Products" (ASTM Designa tion D297). 2.11.5-- Compression set. The per centage of compression set shall not exceed 20. The compression set de termination shall be made in accordance with "Methods of Test for Compression Set of Vulcanized Rubber" (ASTM Designation D395) Method B, with the exception that the disc shall be a 4-in.thick section of the rubber gasket stock. 2.11.6-- Tensile strength after aging. After being subjected to an accelerated aging test for 96 hr in air at 70C in accordance with "Method of Test for Accelerated Aging of Vulcanized Rub ber by the Oven Method" (ASTM Designation D573) or in a pressure chamber for 48 hr at 70C in an oxygen atmosphere at 300 psi in accordance with "Method of Test for Accelerated Aging of Vulcanized Rubber by the Oxygen-Pressure Method" (ASTM Designation D572), the tensile strength of the compound shall be not less than 80 per cent of the tensile strength before aging. 2.11.7-- Shore durometer. The Shore A durometer hardness shall be in the range of 50 to 65 and shall be determined in accordance with "Method of Test for Indentation Hardness of Rubber and Plastics by Means of a Durometer" (ASTM Designation D2240-68) with the exception of Sec. 4 thereof. The determination shall be taken directly on the gasket. 2.11.8-- Test reports. If required by the purchaser, the manufacturer shall submit test reports showing the physi cal properties of the rubber compound used in the manufacture of the gaskets. t CTD014684 PRESTRESSED CONCRETE PRESSURE PIPE 9 Section 3--Design and Fabrication oi Pipe Sec. 3.1--General Requirements 3.1.1--Minimum laying length. In general, pipe shall have a minimum nominal laying length of 16 ft unless shorter lengths are required by weight or other considerations. 3.1.2--Diameter tolerances. Pipe shall be round and true and shall have a smooth and dense interior surface. The mean internal diameter of any por tion of each piece of pipe shall not be less than the design diameter or size specified by more than 3 in. for 36-in. and smaller pipe; by more than | in. for_42rin. and 48-in. pipe; by more than 4 in. for 54- to 78-in. pipe; or by more than 3 in. for 84-in. and larger pipe. 3.1.3-- Core and coating tolerances. The minimum design thickness of the core, including the thickness of the cylinder, shall be fa of the design pipe diameter for normal applications. Thickness of cores shall be not less than the design thickness by more than | in. for 36-in. and smaller pipe; by more than fa in. for 42-in. and 48-in. pipe; by more than 3 in. for 54- to 72in. pipe; or by more than f in. for pipe larger than 72 in. The thickness of the mortar coating shall provide a mini mum cover of f in. over the wire. The thickness of cast concrete coatings shall be 14 in. and shall provide a minimum cover of 1 in. over the core. Sec. 3.2--Design of Pipe 3.2.1--General. The reinforcement of the pipe shall consist of a welded steel cylinder in the core and hightensile wire helically wrapped around the core under measured and uniform tension after the concrete in the core has been placed and cured. The mini^mum thickness of the cylinder shall be 18 gage up to and including 48-in. pipe and shall be 16 gage for 54-in. pipe and larger. The size of the high-tensile wire and the spacing and tension un der which it is wound shall be such that the conditions required by the design methods in Appendix A or B are met. The designs shall fully recognize all losses due to elastic and inelastic defor mations, such as relaxation of the wire and plastic strains in the concrete. The average gross wrapping stress in the high-tensile wire shall not exceed 75 per cent of the minimum ultimate ten sile strength of the wire. The wire shall not be smaller than 0.162 in. in diameter. The minimum centerline spacing of the wire shall be that which produces a clear distance of fV in. be tween wires in the same layer of rein forcement. The centerline spacing of the wire shall not exceed 14 in. For lined-cylinder pipe with wire larger than 0.192 in., the maximum centerline spacing of the wire shall be 1 in. The manufacturer shall submit design cal culations for approval prior to the manufacture of any pipe, if required by the purchaser. 3.2.2--Requirements for normal op erating conditions. Normal operating conditions shall be defined as a combi nation of internal design pressure (as defined in Sec. 1.2.7) and external earth (dead) load. All pipe shall be designed for a com bination of internal design pressure of at least 40 psi and at least 6 ft of earth cover with "ordinary" * bedding, or such greater pressures and earth loads * "Ordinary" bedding is defined as Class C in "Design and Construction of Sanitary and Storm Sewers," Manual of Engineering Practice No. 37, ASCE, Rev. 1969, pp. 212-213. CTD014685 10 AWWA STANDARD as may be specified in the supplemen tary specifications or as shown on the purchaser's drawings. The combination design shall be as described in either Appendix A or B in accordance with standard practice. Maximum internal design pressures for lined-cylinder pipe using minimum core thicknesses, 18gage cylinders, and centrifugal concrete strengths required by Sec. 3.6.8 shall be 250 psi for 16- to 20-in. pipe; 200 psi for 24- to 36-in. pipe; 175 psi for 42-in. pipe; and 150 psi for 48-in. pipe. Higher internal design pressures are permissible using thicker cores, heavier cylinders, or higher concrete strengths, either singly or in combination. Max imum internal design pressures for em bedded-cylinder pipe are limited only by the strength requirements of the component materials. 3.2.3--Provisions for transient con ditions. The design methods for nor mal operating conditions under Ap pendix A or B provide for surge pres sures of at least 40 per cent of design pressure and for live load (including impact) at least equal to American Assn, of State Highway Officials H20 loading. If surge pressure or live load exceeds these limits for a given design condition, such greater value shall be stated in the supplementary specifica tions. In all designs the following combina tions shall not exceed the design limits for the transient-condition require ments of Appendix A or B : (1) design or normal operating pressure plus surge pressure in combination with earth dead load; or (2) design or nor mal operating pressure in combination with earth dead load plus external live load, including impact. Sec. 3.3--Joint Rings The steel bell and spigot joint rings shall be so designed and fabricated that when the pipe is laid it will be self-cen tered. The rings shall be accurately formed and finished to obtain a close, sliding fit for the self-centered surfaces. Each ring shall be formed by one or more pieces of steel butt-welded to gether, either by a resistance welder or by a hand electric weld. Welds on gasket contact surfaces shall be ground smooth and flush with the adjacent sur faces. The rings shall be expanded by a press beyond their elastic limits so that they are accurately sized. On the finished pipe, the circumfer ence of the inside bell-ring contact sur face shall not exceed the circumference of the outside spigot-ring contact sur face by more than W in. for gaskets $4 in. in diameter or less and $ in. for gaskets greater than 4 in. in diameter. The out-of-roundness of either contact surface, measured as the difference be tween the maximum and minimum joint-ring diameters, shall not exceed 0.5 per cent of the average of these diameters. The minimum thickness of the completed bell rings shall be in. for 36-in. and smaller pipe and $ in. for pipe larger than 36 in. The rings tshall conform to the details submitted by the manufacturer and approved by the purchaser.' The joint rings shall be so designed that, when the pipe is laid and the joint completed, the gasket will be enclosed on all four sides. The con tact surfaces shall be such as to prevent cutting of the rubber gasket during in stallation. The portions of the joint rings that will be exposed on the com pleted pipe shall be protected from cor rosion by an approved coating. Sec. 3.4--Rubber Gaskets Joints shall be sealed with a con tinuous solid-ring rubber gasket having a circular cross section with a diam )etral tolerance of 6*1 in. Gaskets shall be of sufficient volume substantially to CTD014686 PRESTRESSED CONCRETE PRESSURE PIPE 11 #fill the recess provided when the pipe joint is assembled, so that the gasket * will be compressed to form a pressuretight seal. The gasket shall be the sole element depended upon to make the joint watertight. Sec. 3.5--Fabrication oi Steel Cylinders 3.5.1-- General. The cylinders shall be formed by shaping and welding to gether cut lengths or coils of specified material and thickness. The cylinders shall be accurately shaped to the size required and the joint rings shall be welded to the ends before testing. 3.5.2--Welding. Butt welding or offset lap welding of the longitudinal and circumferential or helical seams shall be used to produce a smooth and continuous external surface when w'ire is to be wrapped directly on the cylin der. The manufacturer may use either f butt welding or lap welding for longi tudinal and circumferential or helical welds, if the cylinder is encased in the concrete core. Prior to welding, the sheets shall be fitted closely and shall be held firmly during welding. The manu- facturer shall submit for approval, if required, the specific details of ma terials and methods he proposes to use before any welding is done. 3.5.3--Hydrostatic test. Each steel cylinder, with joint rings welded to its ends, shall be subjected to a hydrostatic test. When the cylinder is tested in a horizontal position, the stress shall be at least 20,000 psi but not greater than 25,000 psi. When the cylinder is tested in a vertical position, the stress at the lower end shall be 25,000 psi. While under pressure test, all welds shall be thoroughly inspected and all parts showing leakage shall be marked. Cylinders that show any leakage under test shall be rewelded at the points of leakage and subjected to another hy drostatic test. The finished cylinder, with joint rings attached, shall not be used in the work unless it is completely watertight under the required test pres sure. 3.5.-1--Cleaning steel surfaces. Be fore the concrete core and mortar coat ing are placed, each steel cylinder shall be cleaned to remove loose or other foreign matter that would interfere with the bonding of the concrete and mortar. Sec. 3.6--Concrete for Pipe Core 3.6.1-- General. The concrete in the cores may be placed by the centrifugal method, by the vertical casting method, or by other approved methods. 3.6.2-- Proportioning. The propor tions of cement, fine aggregate, coarse aggregate, and water used in concrete for pipe cores shall be subject to the approval of the purchaser. The propor tions shall be determined and controlled as the work proceeds to obtain homo geneous, dense, workable, durable con crete of specified strength in the walls of the pipe and a minimum of defects in the surface of the pipe. The propor tions shall be those that will give the best overall results with the particular materials and method of placing used for the work. A minimum of six bags of cement shall be used for each cubic yard of concrete. The water-cement ratio shall be such as to assure that the concrete will meet the strength require ments. 3.6.3-- Measurement of materials. A barrel of cement shall be considered as 4 cu ft or 376 lb and a bag of cement shall be considered as 1 cu ft or 94 lb. Cement in standard sacks need not be weighed, but bulk cement shall be weighed. Water for mixing shall be measured by volume or by weight. Concrete aggregates for each batch shall be measured separately by OTD014687 12 AWWA STANDARD weighing-. The proportions of aggre late the compaction of concrete in the gates shall be computed on the satu cores, to produce a spun-cylinder wall rated and surface-dry basis and the wa thickness of about 2 in. The curing of ter-cement ratio shall be exclusive of the test cylinders shall be in conformity water within the aggregates and ab with the curing of the cores. The net sorbed by them. The equivalent unit area of the hollow cylinder shall be weights for both fine and coarse aggre used to determine its compressive gates shall be determined in accordance strength. with the "Method of Test for Unit 3.6.7--Testing cylinders. All test Weight of Aggregate" (ASTM Desig cylinders shall be tested by an ap nation C29). The equipment and de proved testing laboratory at the ex vices for weighing and measuring shall pense of the manufacturer, unless the at all times be accurate within 1 per manufacturer has approved testing cent. facilities at the site of the work. In 3.6.4-- Mixing. The mixing shall be such an event, the tests shall be made done thoroughly by a mixer of ap by and at the expense of the manu proved type. Mixing time shall be con facturer in the presence of the pur sistent with the type of mixer used. chaser, or, if permitted by the pur Transit mixing, shall not be used ex chaser, certified test reports may be cept by written authorization and under submitted by the manufacturer. specific requirement of the purchaser. 3.6.8. --Strength of concrete. Stand 3.6.5-- Standard test cylinders. A ard concrete cylinders shall attain a set of at least four standard test cyl minimum compressive strength of inders shall be taken from each day's 3.000 psi in seven days and 4,500 psi pour of the mixed concrete for pipe in 28 days. Centrifugal test specimens cores made by the centrifugal method, shall attain a minimum compressive the vertical casting method, or other strength of 4,000 psi in seven days and approved methods. Standard test cyl 6.000 psi in 28 days. The compressive inders shall be made in conformance strength at the time of wrapping shall with the "Method for Making and Curing Concrete Compressive and Flexural Test Specimens in the Field" (ASTM Designation C31). The cur conform to the requirements in Sec. 3.8. To conform to the requirements of this section, the average of any ten consecutive strength tests of cylinders ing of the test cylinders shall be in con representing each type of concrete shall formity with the curing of the pipe be equal to or greater than the speci cores. fied strength, and not more than 20 3.6.6-- Centrifugal test cylinders. per cent of the strength tests shall Centrifugally cast test cylinders may be substituted for standard test cylinders, at the option of the manufacturer, when have values less than the specified strength. Pipe made from concrete that does not meet the strength tests in the centrifugal method is used for accordance with the foregoing shall be making cores. A set of at least four subject to rejection. test cylinders shall be taken each day 3.6.9. --Placing concrete by centrif from the mixed concrete for cores. ugal method. The steel pipe cylinder Test cylinders shall be centrifugally with joint rings attached shall be cast in 6-in.-diameter by 12-in.-long placed horizontally in a spinning steel molds spun about their longi machine and may be held by a spinning tudinal axes, at a speed that will simu frame. The spinning machine shall be CTD014688 PRESTRESSED CONCRETE PRESSURE PIPE 13 capable of revolving the cylinders at concrete has set sufficiently to avoid * speeds that will produce concrete meet spalling or damage to the pipe during ly ing the requirements of Sec. 3.6.8 and the process of form removal. 3.8. The method of placing concrete 3.6.11--Other methods of placing the in the cylinder and the speed of rota lining. If the manufacturer proposes tion during placing shall be such that to employ a method other than the cen the concrete will be evenly distributed trifugal or vertical casting method for and well compacted at the specified thickness throughout the length of the pipe. After the concrete has been de posited, the rotation shall be continued placing the concrete lining or core, he shall submit for approval complete de tails of the methods and equipment he proposes to use. at a speed and for a length of time suf ficient to provide the specified strength Sec. 3.7--Curing oi Core and sufficient compaction and bond to permit removal from the spinning 3.7.1-- General. The purpose of cur machine without injury to the pipe ing pipe cores as specified next is to core. Excess water and laitance shall be removed from the interior surfaces of the pipe in an approved manner so that the surface is solid, straight, and obtain concrete of the strength speci fied for test cylinders under Sec. 3.6.8. The cores shall be cured by steam or by water unless otherwise specifically per true. mitted. Water and steam curing may 3.6.10--Placing concrete by vertical be used interchangeably on a time ratio casting method. The concrete lining basis of 4 hr of water curing to 1 hr of A or core shall be cast on end on a cast- steam curing, except that water curing TM iron or steel base ring with rigid steel may be used only if the minimum am collapsible forms for the concrete sur bient temperature exceeds 40F. faces. The forms shall be so designed 3.7.2-- Steam curing. The cores that they will have smooth contact sur shall be placed in the steam-curing faces and tight joints and will be firmly chamber or otherwise covered by a and accurately held in proper position suitable enclosure that will allow pro f without distortion during the placing of per circulation of steam. A delay the concrete. The forms shall be pro period of from 1 to 4 hr shall be allowed vided with top and bottom stiffening before moist steam is admitted in con rings and shall be designed to permit tact with the cores. The temperature removal without injury to the inside within the enclosure shall be gradually surface of the pipe. The forms shall raised to at least 11 OF and not more be thoroughly cleaned and oiled be than 150F for a period of at least 24 fore each use. The transporting and hr. The preset time shall be included placing of concrete shall be carried in the 24-hr period. Curing by steam out by approved methods that will not shall be continuous except during a cause the separation of concrete ma period sufficient to remove the forms terials and the displacement of the steel or supporting rings. The forms shall cylinder or forms from their proper not be removed until at least 6 hr after position. Approved methods of me the beginning of curing. After this chanical vibrating shall be used to com minimum 6-hr period, the cores may be pact the concrete in the forms and to "tipped" from their bases and curing Q secure satisfactory interior surfaces. shall be continued by either steam or Forms shall not be removed until the water. CTD014689 14 AWWA STANDARD 3.7.3--Water curing. The cores shall be kept moist by intermittent wa ter spraying for a period of at least 32 hr. The water-curing period shall be continued 1 hr for each hour, in the fir^ 24, during which the ambient tem perature is below 50F. Following this minimum period, they may be "tipped" from their bases and removed to the storage yard where they shall be kept continuously moist by intermittent spraying for an additional period of at least three days. Sec. 3.8--Placing of Wire -Reinforcement The high-tensile wire shall not be wound around the core until the con crete has reached the minimum sevenday compressive strength specified under Sec. 3.6.8 of this standard. The initial compression in the concrete shall not exceed 55 per cent of the com pressive strength of the concrete at the time of wrapping. Methods and equip ment for applying the wire shall be such that it will be wrapped around the core in a helical form at the de signed predetermined spacing and ten sion for the full length of the core, except that at the ends of the core there shall be an extra complete cir cumferential wrap of wire that may be applied at one half the design tension. The number of coils in any 2-ft length of core shall be not less than required by the design. Wire splices shall be capable of withstanding a force equal to the minimum specified ultimate tensile strength of the wire. An chorages of the wire at the ends of the core shall be capable of resisting a force equal to 75 per cent of the speci fied minimum ultimate tensile strength of the wire. If multiple layers of circumferential reinforcement are used, each layer but the last shall be coated with cement mortar applied in accordance with Sec. 3.9 to provide a minimum cover over the reinforcement at least equal to the diameter of the wire and steam-cured in accordance with Sec. 3.10.2 for a period of not less than 8 hr. The first layer of reinforcement shall be wound on the surface of the core, and subse quent layers shall be wound over the previous layers of cement mortar as specified in this section. The final coating of cement mortar shall be ap plied in accordance with Sec. 3.9, shall provide the minimum cover over the reinforcement specified in Sec. 3.1.3, and shall be cured in accordance with Sec. 3.10. Sec. 3.9--Pipe Coating 3.9.1-- General. After the core has been wrapped with high-tensile wire, an exterior mortar or concrete coating shall be applied. 3.9.2-- Mortar coating. Mortar for coating shall consist of one part cement to not more than three parts fine aggre gate. Cement and fine aggregate shall conform to Sec. 2.1 and 2.2 herein. Rebound not to exceed one fourth of the total mix weight may be used, but the resulting mix proportions shall not be leaner than those just specified. Re bound not used within 1 hr shall be discarded. The mortar shall be thoroughly mixed, and, after mixing is completed, it shall be deposited under impact by an approved method so that a dense, durable encasement is ob tained. Concurrently with the mortar coating, a cement slurry consisting of one sack of cement to not more than 8 gal of water shall be applied to the core just ahead of the mortar coating. 3.9.3-- Concrete coating. Concrete for coating shall be of an approved mix. The proportions shall be those that will give the best overall results with the particular materials and CTD014690 prestressed concrete pressure pipe 15 -methods of placing used for the work. A hinimum of seven bags of cement shall e used for each cubic yard of concrete. The fine and coarse aggregates and cement shall meet the requirements of Sec. 2.1, 2.2 and 2.3 of this standard, except that the grading of coarse aggre gate shall be such that it will all pass a f-in. laboratory sieve. The concrete shall be placed and compacted by ap proved methods and equipment to pro duce a dense, durable coating. 3.9.4--Strength. Concrete for coat ing shall develop a minimum com pressive strength of 3,000 psi in seven days and 4,500 psi in 28 days in ac cordance with Sec. 3.6.8. Sec. 3.10--Curing o! Coating 3.10.1--General. The coating out side the core shall be cured by steam or by water unless otherwise specifi cally permitted. Water and steam firing may be used interchangeably on a time ratio basis of 4 hr of water cur ing to 1 hr of steam curing, except that water curing may be used only if the minimum ambient temperature exceeds 40F. Adequate space and facilities shall be provided for proper curing. 3.10.2-- Steam curing. The coated pipe shall be placed in the curing cham ber as soon as practicable after placing the coating and shall be steam-cured as specified under Sec. 3.7.2 fot a period of at least 12 hr. The pipe shall be handled in such a manner as to avoid injury to the coating during transporta tion to and from the curing chamber. 3.10.3-- Water curing. As soon as the coating has set sufficiently, it shall be kept moist by intermittent spraying for a period of at least four days. The water-curing period shall be continued 1 hr for each hour, in the first 24, dur ing which the ambient temperature is below 50F. Sec. 3.11--Seal Coat If the purchaser specifically orders a bituminous seal coat, the materials and application shall comply with the ap propriate provisions of AWWA C104 (ANSI A21.4) insofar as they are applicable. The material shall be ap plied after the pipe is cured. 0 Section 4--Fittings and Special Pipe Sec. 4.1--General Fittings and special pipe shall in clude closures, connections to main line valves, bends, tees, wyes, beveled pipe for curves, and pipe with outlets re quired for manholes, air valves, and blow-offs as shown on the purchaser's drawings or ordered by the purchaser. Fittings shall conform to the details furnished by the purchaser, or, if re quired, to the details furnished by the manufacturer and approved by ^ie purchaser. Fittings shall be either type as described in Sec 4.2 or 4.3 at the option of the manufacturer and shall be designed for the same condi tions as the pipe. Sec. 4.2--Fittings (Type A) Type A fittings are composed of steel cylinders, concrete or mortar lin ing, and reinforced concrete or mortar exterior coating. The steel for the cylinder shall be cut, shaped, and welded to form the properly shaped bend, tee, reducer, or fitting. The welds shall be inspected and the com pleted cylinder shall be tested for 16 AWWA STANDARD tightness by the dye penetrant or other approved method, if specifically re quired by the purchaser. A cage or cages of steel reinforcement with ap proved cross-sectional areas shall be formed around the cylinder and open ings. Longitudinal reinforcement suf ficient for additional stresses in the fitting walls shall be provided. The interior and exterior concrete or mor tar shall be placed in an approved man ner. Curing shall be as specified in Sec. 3.10 herein. 4.3.3--Mortar. Steel plate fittings^k shall be lined with mortar at least J in. ' thick, except at adapter ends or outlets ) but under no conditions shall the lining be less than J in. thick. The exterior shall be coated with mortar at least 1 in. thick. The mortar shall contain not less than one part cement to three parts sand, of a grading approved for the method of application used. 4.3.4--Curing. Mortar-coated fit tings shall be cured by water spraying, by steam, or by curing compounds. Sec. 4.3--Fittings (Type B) Sec. 4.4--Curves, Bends, and "Type B fittings are composed of cut Closures and welded steel plate of approved Long-radius curves and small angu thickness, with mortar coating on in lar changes in pipe alignment shall be terior and exterior surfaces. formed by deflecting joints, by straight 4.3.1-- Steel plate. The steel for the pipe with beveled ends, by bevel adap fabricated steel plate fittings shall be ters, or by a combination of these. cut, shaped, and welded so that the Pipe ends may be beveled up to 5 deg. finished fitting shall have the required Short-radius curves and closures shall shape and interior dimensions. The be formed by fittings. * deflection angle between adjacent seg ments of a bend shall be not greater Sec. 4.5--Openings and Connections than 22} deg. Adjacent segments Manholes and flanges, spigot or bell shall be joined by lap or butt welding. connections for air valves, blowoffs, or Fabrication and welding shall conform connections to other pipe shall be built to the requirements of Sec. 3.5.1 and into the walls of the concrete pipe at. 3.5.2 of this standard. The welds locations shown on the purchaser's shall be inspected and the completed drawings or ordered by the purchaser. cylinder shall be tested for tightness by Wall openings shall be suitably rein the dye penetrant or other approved forced. The high-tensile wire shall be method, if specifically required by the securely fastened on each side of the purchaser. outlet or shall be wrapped continuously 4.3.2-- Reinforcement. Wire mesh from one side of the opening to the reinforcing shall be applied to the in other. The casting or fabricated outlet terior and exterior surfaces of the shall be welded to the saddle plate or fabricated fitting. Mesh shall be 2- by saddle neck after the hole is cut through 4-in. W1 welded-wire fabric, held f the plate, cylinder, and concrete. If in. from the surfaces of the steel plate. required, the interior and exterior sur The members on the 2-in. spacing shall faces of structural-steel connections extend circumferentially around the shall be lined and coated with mortar. fitting with ends overlapped 4 in. and Alternative outlet designs may be used, tied together. Longitudinal splices if specifically approved by the pur shall be staggered. chaser. CTD014692 PRESTRESSED CONCRETE PRESSURE PIPE 17 Appendix A Cubic Parabola Design Method This appendix is for information only and is not part of AWIVA CS01-72 The wire area, tension, and spacing under which the wire is wound and the core thickness shall be varied so that the specific combination of design pressure and earth load will fall on or under the design curves in Fig. A (a and b). The resulting design has a transient-load capacity equal to the difference between the design pressure or earth load and the value determined from the extension of the appropriate line for surge pressure or live load until it intersects the transient-load curve. If surge pressure exceeds 40 per cent of design pressure or live load (in cluding impact) exceeds the American Association of State Highway Officials H-20 loading, this greater value should be stated in the supplementary speci fications. The design curve is defined by the /'following equation: earth load, in combination with design pressure p. Three-edge-bearing values of Wc used for design shall be conservatively based on the manufacturer's accumu lated test results. Supporting test data shall be provided if required by the engineer. in which P,, is the internal pressure re quired to overcome all compression in the core concrete, exclusive of the ef fect of external load; IV,, is nine tenths of the three-edge-bearing load produc ing incipient cracking in the core, with no internal pressure; /> is the maxi mum design pressure in combination with three-edge-bearing load, w, and is not to exceed 0.8 P for lined cylinder pipe [Fig. A (a) ] ; w is the maximum ^Lihree-edge-bearing load, equivalent to Tig. A. Design and Transient-Capacity Corves for Lined and Embedded Cylinder Pipe Using Coble Parabola Design Method Graph (a) is for lined- and Graph b) for embedded-cylinder pipe. In both graphs, T designates the transient-Uiad curve and D the design curve; wt is for the three-edge-bearing load equivalent to live load; and Ptp is for surge pressure in excess of the normal operating or design pressure. CTD014693 18 AWWA STANDARD Appendix B Stress Analysis Design Method ^ This appendix is for information only and is not part of AWWA C301-72 External Load (Field) The wire area, tension, and spacing under which the wire is wound and the core thickness shall be varied so that the specific combination of design pressure and earth load will fall on or under the design curve illustrated in Fig. B (a and b). The resulting design has a transient-load capacity equal to the difference between the design pressure or earth load and the value determined from the extension of the appropriate line for surge pres sure or live load until it intersects the transient-load curve. If surge pressure exceeds 40 per cent of design pressure, or live load (including im pact) exceeds the American Associa tion of State Highway Officials H-20 loading, this greater value should be stated in the supplementary specifica tions. The design curve is defined by th"> following equation: P [U + 7.5 V/'. - M S fl A, A,J 12J?r Fig. B. Design and Transient-Capacity Curves for Lined and Embedded Cylinder Pipe Using Stress Analysis Design Method Graph (a) is for lined- and Graph (6) embedded-cylinder pipe. In both graphs, T designates the transient-load curve and D the design curve; P0 is the internal pressure required to overcome all com pression in the core concrete, exclusive of the effect of external load; P,p is the surge pressure in excess of the normal operating or design pressure; Wd is the maximum design field external load with internal pressure equal to zero; and w, is the live load in excess of the external dead load. in which p is the maximum design pressure in combination with field ex-i, ternal load, w, and is not to exceed 0. M P,, for lined-cylinder pipe [Fig. B(a)] ; fa- is the resultant induced compres sion; 7.5 Vf is the allowable tensile stress where fe is the specified 28-day compressive strength of the concrete; M is the total moment in the pipe sec tion due to pipe weight, water weight, and external load; F is the total thrust in the pipe section due to pipe weight, water weight, and external load; 5" is the section modulus of the control pipe section based on the total pipe wall at the crown and invert sections and on the core only at the side section; At is the transformed cross-sectional area CTD014694 PRESTRESSED CONCRETE PRESSURE PIPE 19 r* of the control section based on the total of which are to be found in "Coeffi ^ pipe wall at the crown and invert sec- cients for Large Horizontal Pipes," by r tions and on the core only at the side J. H. Paris [Eng. News-Record, vol. section; and R, is the outside radius of 87, p. 768 (1921)]; and "Stress Anal steel cylinder. ysis of Concrete Pipe," by H. C. The coefficients for moment and Olander [Eng. Monograph No. 6 US thrust calculations shall be from recog Bureau of Reclamation, Dept, of the nized and accepted theories, examples Interior, Washington, D.C.]. c c CTD014695 SP--4M--4/78--43301 CTD014696