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PLAINTIFFS EXHIBIT CT-1264 Americnn Wnlor Marks Association AWWA C300-74 Revision of AWWA C300-64 AWWA STANDARD for REINFORCED CONCRETE PRESSURE PIPE, STEEL CYLINDER TYPE, FOR WATER AND OTHER LIQUIDS First edition approved by AWWA Board of Directors Dec. 11,1917. This edition approved fan. 23,1974. AMERICAN WATER WORKS ASSOCIATION 6666 West Quincy Avenue, Denver, Colo. 80235 CTD000452 Committee Personnel The subcommittees that reviewed and developed this revision had the follow ing personnel at that time : Subcommittee on Revision of AWWA Co00 Richard E. Morris Jr., Chairman M. E. Barber S. E. Dore Jr. James H. Bailf.y W. R. Dana Subcommittee on Design Appendices E. L. Wright, Chairman R. A. Skinner C. E. Beal W. Brunzell L. R. Keyser The Standards Committtee on Concrete Pressure Pipe, which reviewed and approved this standard, had the following personnel at the time of approval: Walter K. Neubauer, Chairman Richard E. Morris Jr., Vice-Chairman Joseph A. Willet, Secretary Copyright 1974 by the American Water Works Assn , Inc. Made in USA 11 CTD000453 Committee Personnel (Continued) Consumer/General Interest Members M. E. Barber, Bd. of Water Commissioners, Denver, Colo. C. E. Beal, Metropolitan Utilities Dist., Omaha, Neb. Wayne Brunzell, Schact-Johnson Assocs., Inc., Chicago, 111. S. E. Dore (NEWWA Alternate), Consulting Engr., Barnstable, Mass. S. E. Dore Jr. (NEWWA Repr.), Coffin & Richardson, Inc., Boston, Mass. T. C. Earl, American Water Works Service Co., Philadelphia, Pa. I. L. Geren, Dept, of Utilities, Salem, Ore. J. O. Grimsley, US Bureau of Reclamation, Denver, Colo. S. B. Maynard, Ayres, Lewis, Norris & May, Ann Arbor, Mich. A. C. Michael, (Retired), Detroit, Mich. R. E. Morris Jr., Water Utilities Dept., Dallas, Tex. W. K. Nel'bacer. O'Brien & Gere Engineers, Inc., Syracuse, N.Y. C. A. Parthum (NEWWA Alternate) Camp, Dresser & McKee, Boston, Mass. H. F. Peckworth, Consulting Engr., Richmond, Me. Alexander Scalzitti, Dept, of Water & Sewers, Chicago, 111. R. A. Skinner, (Retired), Los Angeles, Calif. R. T. Tillotson, East Bay Municipal Utility Dist., Oakland, Calif. P. M. Walker, Federal Water Quality Admin., Kansas City, Mo. E. W. Whitlock, Malcolm Pirnie. Inc., White Plains, N.Y. T. F. Wickser, Dept, of Water & Power, Los Angeles, Calif. Producer Members R. E. Bald, INTERPACE Corp., Parsippany, N.J. J. H. Bailey, Gifford-Hill-American, Inc., Dallas, Tex. W. R. Dana, American Pipe & Construction Co., Monterey Park, Calif. L. R. Keyser, Price Brothers Co., Dayton, Ohio f. A. Willett, American Concrete Pressure Pipe Assn., Arlington, Ya. E. L. Wright, United States Pipe and Foundry Co., Concrete Pipe Baldwin Park, Calif. Div., in CTD000454 i Table of Contents SEC. PACE Foreword I History of Standard ..................... v II Information Regarding Use of This Standard............................. v III Major Revisions ............................. vi Standard 1 General ......................................... 1.1 Scope ................................................. 1.2 Definitions ....................................... 1.3 . Essential Requirements.................. 1.4 Plans and Data to Be Furnished by Purchaser ............................... 1.5 Data to Be Submitted by Manu facturer ......................................... 1.6 Marking ........................................... 1.7 Inspection and Testing by Pur chaser ........................................... 1.8 Material and Workmanship ........ 1.9 Tests ................................................ 1.10 Affidavit of Compliance.................. 1 1 I 2 3 3 3 4 4 2 Material Specifications ............... 4 2.1 Cement ............................................. 4 2.2 Fine Aggregate............................... 5 2.3 Coarse Aggregate ......................... 5 2.4 Samples of Aggregates.................. 6 2.5 Water ............................................... 6 2.6 Admixtures ..................................... 6 2.7 Steel for Cylinders andFittings 6 2.8 Steel for Bar, Wire, and Wire Fabric Reinforcement ................ 6 2.9 Steel for Joint Rings ................... 7 2.10 Steel Casting for Fittings.............. 7 2.11 Rubber for Gaskets ................... 7 SEC. PACE 3 Design and Fabrication of Pipe 8 3.1 General Requirements .................. 8 3.2 Design of Pipe......................... 8 3.3 Joint Rings ..................................... 9 3.4 Rubber Gaskets ............................. 9 3.5 Fabrication of Steel Cylinders ... 9 3.6 Fabrication of Reinforcement Cage 10 3.7 Concrete for Pipe.................... 10 3.8 Curing of Pipe ............................... 12 3.9 Seal Coat ......................................... 12 4 Fittings and Special Pipe .......... 12 4.1 General ............................................ 12 4.2 Fittings (Type A) ......................... 13 4.3 Fittings (Type B) ......................... 13 4.4 Curves, Bends, and Closures .... 13 4.5 Openings and Connections .......... 14 cy Appendix A--Design Requirements A l General .............................................. 14 A2 Hydrostatic Design ......................... 14 A3 Combined Load Design ................. 14 A4 Reinforcement Cage Configura- tions .............................................. 15 Tables 1 Gradation Requirements for Fine Aggregate ................................... 5 2 Permissible Amounts of Deleteri ous Substances in Coarse Ag gregate ......................................... 5 3 Requirements for Pipe of Various Sizes ............................................. 9 iv CTD000455 Foreword This forcvrord is for information and is not a (<art of AIVWA C300-74. I--History of Standard In April 1943, the AWWA Board of Directors authorized the preparation of "Tentative Emergency Specifications for Concrete Pressure Pipe." They covered a number of different types in a single document and served a useful purpose during the Second World War but are now obsolete and have been withdrawn. The first standard prepared by AWWA Water Works Practice Com mittee 8320D--Reinforced Concrete Pipe, which was formed in 1946, cov ered the manufacture of reinforced concrete pipe, steel cylinder type, not prestressed. The standard is now designated AWWA C300. This type of pipe, first manufactured in 1919, consists of a welded steel cylinder with a steel joint ring welded at each end; a cage or cages of steel rein forcing bars or wire externally concen tric with the cylinder; an encasing wall of dense concrete; and a pre formed gasket of rubber to provide the joint seal between adjacent pipes. The pipe is manufactured in sizes ranging from 24 in. to more than 144 in. in diameter. Reinforced concrete pipe, steel cyl inder type, is designed for the specific combination of internal pressure and external load required for the project in accordance with the procedures out lined in the appendix of this standard. The pipe is normally limited in design to pressures of up to 260 psi. This type of pipe is used for trans mission mains, distribution feeder mains, pressure siphons, industrial pressure lines, sewer force mains, and sewer outfall lines. The pipe is manufactured by first fabricating the steel cylinder and hy drostatically testing it with joint rings attached. Then, after the reinforcing cage(s) and steel cylinder have been assembled within a form, a concrete encasement is vertically cast, accom panied by mechanical vibration. Cur ing of the concrete is accomplished bymeans of water or steam. The pipe is generally made in 12- through 24-ft laying lengths. The circumferential steel of the cage provides 40 to 80 per cent of the reinforcement, depending on the conditions for which the pipe is de signed. The first edition of this standard was approved as "Tentative" on Dec. 11, 1947. It was revised and approved as "Standard" on Jan. 13, 1952. The second edition was approved as "Tenta tive" on Jul. 19, 1957, and made "Stan dard" on Jan. 27, 1964. Installation of this pipe is covered by AWWA Manual M-9, "Installation of Concrete Pipe." II--Information Regarding Use of This Standard When purchasing pipe under the provisions of this standard, the pur chaser shall furnish supplementary spe cifications that include specific details CTD000456 VI CONCRETE riPE--NOT TRESTRESSED oil the following: 1. Standard used; that is, AWWA C300-74. 2. Manner of storage and delivery if required of the manufacturer. 3. The working pressure, the transient pressure, the depth of earth cover, the trench bedding condition, and the live load for which the pipe is to be de signed (Sec. 1.4.1). 4. Whether pipe may be supplied from inventory (Sec. 1.5.1). 5. Whether a tabulated layout sched ule (Sec. 1.5.2) will be required. 6. Identification marks required (Sec. 1.6). 7. Whether elliptical reinforcement is acceptable (Sec. 1.6 and Appendix A4). 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. Testing of welds (Sec. 1.9.6) if required. 12. Whether an affidavit of compli ance (Sec. 1.10) will be required. 13. Type of cement required if there is a preference (Sec. 2.1.1). 14. Whether aggregate samples (Sec. 2.4) will be required. 15. Whether submission of manufac turer's design calculations (Sec. 3.2) will be required. 16. Type of protective coating on ex posed portions of joint rings (Sec. 3.3.3) if there is a preference. 17. Whether submission for approval of details of materials and methods for welding (Sec. 3.5 and 3.6) will be required. 18. Whether a specific seal coat (Sec. 3.9) will be required. 19. Details of fittings (Sec. 4.1). 20. Testing of steel cylinders for fittings (Sec. 4.2 and 4.3). 21. Whether lining and coating of structural steel connections (Sec. 4.5) will be required. 22. Variance in curing if permitted (Sec. 3.8.1). Ill--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." the term "not prestressed" was elimi nated as redundant, and the following phrase was added: "for water and other liquids." 2. The entire standard was care fully reviewed, and changes were made in most of the sections to improve understanding and readability. 3. Use of the standard was improved by the addition of titles to all sections. 4. The format and terminology of the standard are patterned after AWWA C301-72 to establish a consistency in concrete pressure pipe standards. 5. The scope, which formely pro vided for pipe in sizes from 20 in. to 96 in., was changed to provide for sizes from 24 in. to 144 in. This change was made to conform to pres ent industry practice. 6. Concrete admixtures for reducing water content and controlling setting time may be used by the manufacturer as provided in Sec. 2.6. 7. The laying length of pipe, pre viously required to be nominally 12, 14, or 16 ft, is now set at a minimum of 8 ft and a maximum of 20 ft for CTD000457 FOREWORD vii 24-in. to 39-in. pipe and 24 ft for 49-in. pipe and larger. 8. 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 reduction does not re lax the concrete strength requirements. 9. A design appendix has been added to the standard to provide a method of designing reinforced concrete cylinder pipe to resist internal pressures and ex ternal loads. This appendix provides a uniform approach to design so that the user of the standard will find it easier to undertake the design of the pipe and to review the manufacturer's computations. By incorporating all the design considerations in the ap pendix, it was possible to simplify Sec. 3, Design and Fabrication of Pipe. CTD000458 AWWA Standard tor Ai nencan Water Works Association AWWA C300-74 Revision of AWWA C300-64 Reinforced Concrete Pressure Pipe, Steel Cylinder Type, for Water and Other Liquids Section 1--General Sec. 1.1--Scope This standard covers the manufac ture of reinforced concrete cylinder pipe that is not prestressed or preten sioned and is in sizes from 24 to 144 in., inclusive.* This type of pipe is designed for working pressures of 40 psi and higher that are combined with external loading conditions designated by the purchaser. This standard does not include requirements for handling, delivery, laying, field testing, or dis infection of the pipe. Sec. 1.2--Definitions In this standard, the following defini tions shall apply: 1.2.1 Purchaser. The word "pur chaser" shall mean a person, firm, corporation, 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 ~ ripe may oe manuiaciurea in i diameters provided the purchaser is ir accord with the design. corporation executing the contract or agreement with the purchaser to fur nish pipe and fittings according to this standard. 1.2.3 Manufacturer. The word "manufacturer" shall mean the person, firm, or corporation that actually manu factures the pipe, acting either directly as the contractor or as a subcontractor or supplier. If the manufacturer is acting as a subcontractor under the contractor or otherwise as a supplier to the contractor, the obligations of the manufacturer under this standard shall be considered as obligations of the con tractor, and the contractor shall be re sponsible for the performance. 1.2.4 ASTM. The term "ASTM" does mean the American Society for Testing and Materials. When specific ASTM specifications are cited without dates, the designation shall be con strued as referring either to the latest revision under the same specification number or to superseding specifications under a new number, except for pro visions in the revised specifications that clearly are inapplicable. CTD000459 2 CONCRETE PIPE-NOT PRESTRESSED 1.2.5 ANSI. The term "ANSI" does mean the American National Standards Institute, Inc. 1.2.6 Approved. The term "ap proved" shall mean having received the approval of the purchaser. 1.2.7 Working pressure. The working pressure shall be the maxi mum sustained internal hydrostatic pressure to which the pipe is to be subjected. 1.2.8 Transient pressures. Tran sient pressures are internal pressure overloads of relatively short duration in excess of working pressure. 1.2.9 Dead loads. Dead loads are those loads due to the weights of the earth over the pipe, the water con tained by the pipe, and the pipe itself. 1.2.10 Live loads. Live loads are those loads that result from the pass age of vehicles over the installed pipe. 1.2.11 Pipe diameter. The term "pipe diameter" or "size" shall mean the design inside (waterway) diameter of the pipe. Sec. 1.3--Essential Requirements The pipe shall have the following principal features: a welded steel cylinder with steel joint rings welded to its ends; a reinforcing cage or cages of steel bars, wire, or welded wire fabric surrounding the steel cylinder; a wall of dense concrete covering the steel cylinder and reinforcing cage or cages inside and out; and a joint with a preformed gasket of rubber, so de signed that the joint will be watertight under all conditions of service. Sec. 1.4--Plans and Data to Be Furnished by Purchaser 1.4.1 Design data. The purchaser shall designate the working pressure, the transient pressure, the depth of earth cover, the trench bedding con dition, and the live load for which the pipe shall be manufactured. 1.4.2 Plans. At least one month prior to manufacture, the purchaser shall furnish the contractor plans and profiles showing the following: align ment and grades; the location of all outlets, connections, and special ap purtenances ; the design pressures for each part of the line; and such special details or information as are necessary for the manufacture of the pipe and fittings in accordance with this standard and with the specific requirements of the work for which the pipe is made. Sec. 1.5--Data to Be Submitted by Manufacturer 1.5.1 Detailed draivings and sched ules. The manufacturer shall submit for approval of the purchaser drawings and schedules showing full details of the 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, and the point of change from one zone to the next shall be clearly indicated by sta tion number. The diameter of the pipe, the working pressure and thick ness of pipe wall, and the area of steel (per linear foot of pipe) in the reinforcing cage or cages and steel cylinder shall be listed for each portion of the pipeline. CTD000460 SECTION 1--GENERAL 3 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 the working pressure for which the pipe or fitting is designed. Special marks or identification sufficient to show the proper location of the pipe or fitting in the line by reference to layout drawings and schedules specified 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. If elliptical rein forcement is used, the minor axis of the reinforcement shall be identified. 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 manu facturer's plant, the purchaser shall so specify in the contract or agreement, stating the conditions (such as the time and the extent of inspection) under which the inspection shall be made. 1.7.2 Access to zvork. 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 such assistance as is necessary for the handling of pipe and fittings. 1.7.3 Responsibility. Inspection by the purchaser or failure of the pur chaser to provide inspection shall not relieve the manufacturer of his respon sibility to furnish materials and to per form work in accordance with this standard. 1.7.4 Tests. Tests under Sec. 1.9 that the purchaser makes on material samples shall be made without delay. If any sample fails to meet the require ments, the manufacturer shall be noti fied immediately. Material affected by the test results shall be set aside pend ing final disposition. The manufacturer may then request a review of test pro cedures and additional tests on the ma terial. Duplicate samples, the number of which is to be agreed upon, should be tested by the purchaser or his repre sentative and by the manufacturer. The manufacturer's tests shall be per formed by a commercial testing labora tory or in the manufacturer's labora tory, 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 accepted. If the material is rejected after retesting, the manu facturer shall pay all costs of retesting. 1.7.5 Rejection. Material, fabri cated parts, and pipe that are dis covered to be defective or that do not conform to the requirements of this standard will be subject to rejection at any time prior to final acceptance of the pipe. Rejected material and pipe shall be promptly removed from the site of the work. Sec. 1.8--Material and Workman ship All material furnished by the manu facturer shall be new and of the quality specified. All work shall be done in a thorough, workmanlike manner by me chanics skilled in their various trades. When a lower limit or minimum di mension is given herein for a steel com CTD000461 4 CONCRETE PITE-NOT PRESTRESSED ponent, the minus tolerance (as stated in the applicable ASTM specification) for such limit or dimension shall be understood to define the true lower limit or dimension. Sec. 1.9--Tests 1.9.1 Cylinder assembly. Each completed cylinder with joint rings welded to its ends shall be subjected to a hydrostatic test as specified under Sec. 3.5.3. 1.9.2 Concrete. Samples of the mixed concrete shall be taken for mak ing compression test cylinders as speci fied under Sec. 3.7.4. 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 re quest. 1.9.4 Steel specimens. If required by the purchaser, the manufacturer shall provide test specimens cut from each shipment of steel for reinforcing and for cylinders. 1.9.5 Gasket rubber. Test reports showing the physical properties of rub ber used in the gaskets, as specified in Sec. 2.11.8, shall be obtained by the manufacturer and shall be made avail able to the purchaser on request. 1.9.6 IVelds in reinforcement. If required by the purchaser, samples of welds in reinforcing bars shall be tested for conformance with Sec. 3.6. 1.9.7 Expense. The expense of testing materials and submitting test reports to the purchaser in accordance with this standard and the purchaser's supplementary specifications, referred to in the foreword, of testing the com pleted steel 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 purchaser's expense, except as otherwise specificially 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 comply with all applicable provisions of this standard. Section 2--Material Specifications Sec. 2.1--Cement 2.1.1 Type. Cement for concrete work shall conform to the "Specifica tions for Portland Cement" (ASTM Designation Cl50). Either Type I or Type II may be used unless the pur chaser specifies a particular type. Sampling and testing shall conform to the individual ATSM specification designated therein. 2.1.2 Inspection. Satisfactory fa cilities shall be provided for identifying, inspecting, and sampling cement at the mill, the warehouse, and the site of the work. The purchaser shall have the right to inspect the cement and obtain samples for testing at any of these points. 2.1.3 Storage. Cement shall be stored in a weathertight, dry, wellventilated structure. 2.1.4 Unusable. Cement salvaged bv cleaning cement sacks, mechanically or otherwise, shall not be used in the work. Cement containing lumps shall be rejected and shall be immediately re moved from the site of the work'. CTD000462 SECTION 2--MATERIAL SPECIFICATIONS 0 2.1.5 Temperature. If the tem perature of the cement exceeds 150F, it shall be stored until cooled to that temperature. Sac. 2.2--Fine Aggregate 2.2.1 General. Fine aggregate for concrete and mortar shall consist of clean, hard, durable, uncoated particles of natural sand or of sand prepared from the product obtained by crush ing stone or gravel. At the time of use the fine aggregate shall be entirely free of frozen material. 2.2.2 Gradation. Fine aggregate shall be well graded from coarse to fine and, when tested by means of lab oratory sieves in accordance with the "Method of Test for Sieve or Screen Analysis of Fine and Coarse Aggre gates" (ASTM Designation Cl36), shall conform to the gradation require ments in Table 1. TABLE 1 Gradation Requirements for Fine -1ggeegnte Sieve Size Total Passing, hy Weight. % i in. Xo. 4 Xo. 8 Xo. 16 Xo. 40 Xo. 50 Xo. 100 100 95-100 65- 98 45- 80 20- 70 5- 50 2- 10 0- 5 o X The gradation requirements given in Table 1 represent the extreme limits for determining the suitability of fine aggregate under this standard. To maintain uniformity of gradation for aggregate from any given source, a fineness modulus determination shall be made upon representative samples from that source. Thereafter the fine ness modulus of all shipments there from shall not vary by more than 0.20 from the fineness modulus of the repre sentative sample, unless suitable, ap proved mix adjustments 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 Designa tion C33-71a). Sec. 2.3--Coarse Aggregate 2.3.1 General. Coarse aggregate for concrete shall consist either of hard, durable particles of crushed stone or of crushed or uncrushed gravel that con forms to the requirements and tests given in Sec. 2.3.2 and 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 pur chaser and shall be such that the con crete can be readily placed in the mold, by the particular method used in plac ing it, to provide a solid, compact, homogeneous wall with a smooth sur face. 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 C136). Thin and elongated pieces, the maximum dimension of which exceeds five times the minimum, shall not be TABLE 2 Permissible Amounts of Deleterious Substances in Coarse Aggregate Material Soft particles Coal and lignite Clay lumps Material finer than 200 sieve Combined total of above items Maximum Weight Limit. cc 5.00 0.50 0.25 1.00 5.00 CTD000463 6 CONCRETE PIPE--NOT PRESTRESSED in excess of 10 per cent of the coarse aggregate by weight. 2.3.3 Impurities. Deleterious sub stances in coarse aggregate shall not exceed the amounts given in Table 2, as determined by sampling and testing procedures listed in the "Specifications for Concrete Aggregates" (ASTM Designation C33). Sec. 2.4--Samples of Aggregates At least four weeks prior to mixing concrete, the manufacturer, if required, shall provide, in suitable containers, samples of not less than 1 cu ft each of fine aggregate and coarse aggregate for preliminary approval. 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 accord ance with the "Methods of Sampling Aggregates" (ASTM Designation D75). Sec. 2.5--Water Water used for concrete and for curing 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-reduc ing, set-controlling admixture conform ing to the "Specification for Chemical Admixtures for Concrete" (ASTM Designation C494). No admixture shall contain calcium chloride. The type and amount of admixture shall be subject to the approval of the pur chaser. Sec. 2.7--Steel for Cylinders and Fittings 2.7.1 Steel sheets. Steel sheets for pipe cylinders and fittings mav be in cut lengths or coils and shall meet the requirements of the "Specifications for Hot-Rolled Carbon Steel Sheets and ^ Strip, Structural Quality" (ASTM^j' Designation A570), Grade B or C, or^ "Specifications for Hot-Rolled Carbon Steel Sheets and Strip, Commercial Quality" (ASTM Designation A569), except that for steel covered by ASTM A569, the maximum carbon content shall be 0.25 per cent and the minimum yield shall be 27,000 psi. 2.7.2 Steel plates. Steel plates for pipe cylinders and fittings shall con form to the "Specifications for Low and Intermediate Tensile Strength Carbon Steel Plates for Structural Quality" (ASTM Designation A283), Grade B or C. Sec. 2.8--Steel for Bar, Wire, and Wire Fabric Reinforcement 2.8.1 Bars. Steel bar reinforce ment for concrete pipe or fittings shall be plain or deformed and shall con- B form to "Specifications for Carbon Steel Bars Subject to Mechanical Property Requirements" (ASTM Designation A306), Grade SO, or to "Specifications for Deformed BilletSteel Bars for Concrete Reinforcement" (ASTM Designation A615-68), IP Grade 40, except that for plain bars supplied under ASTM A615-68, (1) the requirements of Sections 6, 7, and 14.3 shall not apply, (2) intermediate bar diameters shall meet the require ments of the next smaller bar number designation, and (3) bar diameters less than No. 3 shall meet the requirements for No. 3 bar. 2.8.2 Wire. Steel wire for rein forcement of concrete pipe shall con form to the "Specifications for ColdDrawn Steel Wire for Concrete Rein forcement" (ASTM Designation A82') or to the "Specifications for Deformed Steel Wire for Concrete Reinforce- CTD000464 SECTION 2--MATERIAL SPECIFICATIONS / ment" (ASTM Designation A496). Wire used for ties may be annealed. 2.S.3 Wire fabric. Wire fabric reinforcement for concrete pipe or for mortar coating for fittings shall con form either to the "Specifications for Welded Steel Wire Fabric for Con crete Reinforcement'' (ASTM Desig nation A185) or to the "Specification for Welded Deformed Steel Wire Fabric for Concrete Reinforcement" (ASTM Designation A497). Sec. 2.9--Steel for Joint Rings Steel for bell rings less than in. thick shall conform to "Specifications for Hot-Rolled Carbon Steel Sheets and Strip, Structural Quality" (ASTM Designation A570), Grade A, or to "Specifications for Hot-Rolled Carbon Steel Sheets and Strip, Commercial Quality" (ASTM Designation A569). Special shapes for spigot joint rings and steel for bell rings i in. or more 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 Intermediate Tensile Strength Carbon Steel Plates of Structural Quality" (ASTM Designation A283), Grade A, or to "Specifications for Merchant Quality Hot-Rolled Carbon Steel Bars" (ASTM Designation A575), Grade 1012, or to "Specifications for Special Quality Hot-Rolled Carbon Steel Bars" (ASTM Designation A576), Grade 1012, or to "Specifica tions for Steel Sheet and Strip, Carbon, Hot-Rolled Commercial Quality, Heavy-Thickness Coils (Formerly Plate)" (ASTM Designation 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 Castings for General Application" (ASTM Designation A27), Grade 7036, normalized. 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 contain not less than 50 per cent by volume of first-grade natural crude or first-grade synthetic rubber. The re mainder of the compound shall consist of pulverized fillers free from rubber substitutes, reclaimed rubber, and del eterious substances. The compound shall meet the following physical re quirements when tested, in accordance with the indicated conditions and designated 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 Designation D412). 2.11.4 Specific gravity. The spe cific gravity shall not vary by more than 0.05 within the range of 0.951.45--"Methods for Chemical Analysis of Rubber Products" (ASTM Desig nation 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 Compres- CTD000465 8 CONCRETE PIPE-NOT PRESTRESSED sion 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 SO per cent of the tensile strength be fore 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 Hard ness of Rubber and Plastics by Means of a Durometer" (ASTM Designation D2240-68), with the exception of Sec tion 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. Section 3--Design and Fabrication of Pipe Sec. 3.1--General Requirements 3.1.1 Laying lengths. In general, pipe shall have a minimum nominal laying length of 8 ft, unless shorter lengths are required by weight or other considerations. The maximum lengths shall be as follows: Internal Diameter in. 24 to 36 inclusive 39 and larger Maximum Laying Length n 20 24 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 be not less than the design diameter or size specified by more than 4 in. for 36-in. pipe, and smaller; by more than in. for 42-in. and 48-in. pipe; by more than 4 in. for 54-in. to 78-in. pipe; or hv more than { in. for S4-in. pipe, and larger. 3.1.3 Wall tolerances. The mini mum design thickness of pipe wall and the minimum thickness of concrete lin ing for each size of pipe shall be as shown in Table 3. At the spigot sec tion, the concrete lining thickness may be less than shown in Table 3, provided that the interior surface of the lining at the spigot shall not depart from a true right cylinder projected from the interior surface of the lining in the body of the pipe. The thickness of walls shall be not less than the design thickness by more than 4 in. for 36-in. pipe, and smaller; by more than yV in. for 42-in. and 48-in. pipe; by more than I in. for 54-in. to 72-in. pipe; or by more than 4 in. for pipe larger than 72 in. Sec. 3.2--Design of Pipe The reinforcement of the pipe shall consist of a welded steel cylinder sur rounded by one or more cages of welded steel hoops, helically wound steel bar or wire, or welded wire fabric CTD000466 SECTION .1--DESIGN 9 TARLE 3 Requirements for Pipe of Various Sizes* Pipe ID in. 24 3(J 36 42 48 54 60 66 72 78 84 90 96 Minimum Thickness Total Pipe Wall in. 31 3J 4 41 5 51 6 61 7 71 8 8 8} Concrete Lining in. i i t i il U il il il if il if if * For pipe larger than 96 in. in diameter, dimensions and details of design shall be subject to approval by the purchaser. properly spaced and supported with longitudinal reinforcing. The mini mum thickness of the cylinder shall be 16 gage. The cross-sectional area of the circumferential steel in the cylinder and in the reinforcing cage or cages shall be such that the conditions re quired by the design methods in the appendix are met. If required by the purchaser, the manufacturer shall sub mit design calculations for approval prior to the manufacture of any pipe. Sec. 3.3--Joint Rings 3.3.1 General. The steel bell and spigot joint rings shall be so designed and fabricated that when the pipe is laid and the joint completed, the gasket will be enclosed on four sides. Each ring shall be formed by one or more pieces of steel butt-welded together. The contact surfaces in the joint shall be such as not to cause cutting of the rubber gasket during installation. Welds on gasket contact surfaces shall be ground smooth and flush with the adjacent surfaces. The rings shall be expanded by a press beyond their elastic limits so that they are accurately sized. 3.3.2 Tolerances. On the finished pipe, the circumference of the inside bell ring contact surface shall not ex ceed the circumference of the outside spigot ring contact surface by more than in. for gaskets jji in. in diam eter or by more than J in. for gaskets greater than in. in diameter. The out-of-roundness of either contact sur face, 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 W in. for 36-in. pipe, and smaller, and } in. for pipe larger than 36 in. The rings shall conform to the details submitted by the manufacturer and approved by the purchaser. 3.3.3 Protective coating. The por tions of the joint rings that will be ex posed on the completed pipe shall be protected from corrosion by an ap proved 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 diametral tolerance of in. Gaskets shall be of sufficient volume to fill substantially the recess provided when the pipe joint is assembled, so that the gasket will be compressed to form a pressure- tight seal. The gasket shall be the sole element depended upon to make the joint watertight. Sec. 3.5--Fabrication of Steel Cy linders 3.5.1 General. The cylinders shall be formed by shaping and welding to CTD000467 1 i 10 CONCRETE PIPE-NOT TRESTRESSED 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, lap welding, or offset lap-welding, shall be used for the longitudinal and circum ferential or helical seams. The sheets shall be closely fitted prior to welding and shall be firmly held during welding. If required, the manufacturer shall sub mit for approval the specific details of materials 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 hydro static 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 revvelded 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. 3.5.4 Cleaning steel surfaces. Be fore the concrete is placed, steel sur faces shall be cleaned to remove loose or other foreign matter that would interfere with the bonding of the con crete. Sec. 3.6--Fabrication of Reinforce ment Cage 3.6.1 Circumferential reinforcement. The circumferential reinforcement shall either be steel bar or wire in helical or hoop form or be welded wire fabric shaped and lap- or butt-welded into cages. The quality of the welds and welding procedures shall be assured by the testing of a representative num ber of butt or lap welds to a test stress of 25,000 psi. 3.6.2 Longitudinal reinforcement. The circumferential reinforcement in cages shall be accurately spaced and rigidly assembled by the attaching of longitudinal bars securely, so that the cage is maintained in proper shape and position during the casting of the pipe. 3.6.3 Placement. The minimum distance between the circumferential reinforcing steel and the surface of the pipe shall be 1 in. Sec. 3.7--Concrete for Pipe 3.7.1 Proportioning. The propor tions of cement, fine aggregate, coarse aggregate, and water used in concrete for pipe shall be subject to the approval of the purchaser. The proportions shall be determined and controlled as the work proceeds in order to obtain homogeneous, dense, workable, durable concrete of specified strength in the wall of the pipe and a minimum of de fects in the surface of the pipe. The proportions shall be those that will give the best overall results with the particular materials used for the work. A minimum of six bags of cement shall be used for each cubic yard of con crete. The water-cement ratio shall be such as to assure that the concrete will meet the strength requirements. 3.7.2 Measurement of materials. A barrel of cement shall be considered 4 cu ft or 376 lb, and a bag of cement shall be considered 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. f' * CTD000468 SECTION .1--DESIGN 11 (Concrete aggregates for each batch shall be measured separately by weigh ing. The proportions of aggregates shall be computed on both the saturated and surface-dry basis, and the watercement ratio shall exclude the water ab sorbed by the aggregates. The equiv alent unit weights for both fine and coarse aggregates shall be determined in accordance with the "Method of Test for Unit Weight of Aggregate'' (ASTM Designation C29). The equipment and devices for weighing and measuring shall at all times be accurate within 1 per cent. 3.7.3 Mixing. The mixing shall be thoroughly done by a mixer of ac cepted type. Mixing time shall be consistent with the type of mixer used. Transit mixing shall not be used ex cept by written authorization and under specific requirement of the purchaser. 3.7.4 Standard test cylinders. A set of at least four standard test cyl inders shall be taken from each day's pour of the mixed concrete. Standard test cylinders shall be made in con formance with the "Method for Making and Curing Concrete and Compressive and Flexural Test Specimens in the Field" (ASTM Designation C31). The curing of the test cylinders shall be in conformity with the curing of the pipe. 3.7.5 Testing cylinders. All test cylinders shall be tested by an approved testing laboratory at the expense of the manufacturer, unless the manu facturer has approved testing facilities at the site of the work. In such event, the tests shall be made by the manu facturer in the presence of the pur chaser and at the manufacturer's ex pense or. if permitted by the purchaser, certified test reports may be submitted by the manufacturer. 3.7.6 Strength of concrete. The design strength of concrete shall be the strength used in designing the pipe by the method described in the Design Appendix. The design strength of concrete shall be not less than 4,500 psi for vertically cast concrete or 6,000 psi for centrifugally cast concrete. The compressive strength of concrete cyl inders shall equal or exceed of the design strength in 7 days and the de sign strength in 28 days. To conform to the requirements of this section, the average of any ten consecutive strength tests of cylinders representing each type of concrete shall be equal to or greater than the design strength, and no cylinder shall have a strength less than 80 per cent of the design strength. Damaged cylinders shall be discarded. Pipe made from concrete that does not meet the strength tests in accordance with the foregoing shall be subject to rejection. 3.7.7 Forms. The forms shall be of steel made with butt joints through out and with the interior surface smooth and true. The forms shall be so constructed that the inner and outer forms, joint rings, and reinforcement shall be held in position throughout placing of the concrete and so designed that the pipe can be stripped from the forms rapidly and without damage to the pipe surfaces. Forms shall be suf ficiently tight to prevent leakage of mortar, and they shall be stiff enough and so braced as to withstand, with out deformation, all operations incident to the pouring and setting of the con crete. Forms shall be cleaned and oiled before each use. 3.7.8 Placing concrete. The trans porting and placing of concrete shall be carried out by methods that will not cause the separation of concrete ma terials or the displacement of the steel cylinder and reinforcement from their CTD000469 12 CONCRETE HPE-NOT PRESTRESSED proper positions in the form. Accepted methods of mechanical vibrating shall be used to compact the concrete in the forms and to secure satisfactory interior surfaces. Forms shall not be removed until the concrete has set sufficiently to avoid spalling or damage to the pipe during removal of the form. Sec. 3.8--Curing of Pipe 3.8.1 General. The purpose of cur ing pipe as prescribed in the following sections is to obtain concrete of the strength specified for test cylinders under Sec. 3.7.6. The pipe shall be cured by steam or by water unless otherwise specifically permitted. Wa ter curing and steam curing may be used interchangeably on a time-ratio basis of 4 hr of water to 1 hr of steam curing except that the water curing may be used only if the minimum ambient temperature exceeds 40F. 3.8.2 Steam curing. The pipe shall be placed in the steam-curing chamber or otherwise covered by a suitable en closure that will allow proper circula tion of steam. A delay period of from 1 to 4 hr shall be' allowed before moist steam is admitted to contact the pipe. The temperature within the enclosure shall be gradually raised to at least 110F and to not more than 150F for a period of at least 24 hr. The delay period shall be included in the 24-hr period. Curing by steam shall be con tinuous except during a period suf ficient to remove the forms or support ing rings. The forms shall not be re moved until at least 6 hr after the begining of the curing. After this mini mum 6-hr period, the pipes may be "tipped" from their bases, and curing shall be continued by either steam or water. 3.8.3 Water curing. The pipe shall be kept moist by intermittent water spraying for a period of at least 32 hr. The water-curing period shall be ex tended 1 hr for each hour in the first 24 during which the ambient air tempera ture is below 50F. Following this minimum period, they may be "tipped" from their bases but shall be kept con tinuously moist by intermittent spray ing for an additional period of at least 3 days. Sec. 3.9--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 ap plicable. The material shall be applied after the pipe is cured. Section 4--Fittings and Special Pipe Sec. 4.1--General Fittings and special pipe shall in clude bends, tees, wyes, connections to main-line valves, closures, beveled pipe for curves, and pipe with outlets required for manholes, air valves, and blowoffs, as shown on the purchaser's drawings or as ordered by the pur chaser. Fittings shall conform to the details furnished by the purchaser or, if required, to the details furnished by the manufacturer and approved by the purchaser. Fittings shall be either type CTD000470 SECTION 4- FITTINGS 13 as described in Sec. 4.2 and 4.3 at the option of the manufacturer and shall be designed for the same pressures 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 other fitting. The welds shall be inspected, and the com pleted cylinder shall be tested for tight ness by the dye penetrant method or other approved method, if specifically required 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 the additional stresses in the fitting walls shall be provided. The interior and exterior concrete or mor tar shall be placed in an accepted man ner. Curing shall be as specified in Sec. 3.8. Sec. 4.3--Fittings (Type B) Type B fittings are composed of cut and welded steel plate of a thickness to provide the design strength, with mortar coating on interior and exterior surfaces. 4.3.1. Steel fabrication. The steel for the fabricated steel plate fittings shall be cut, shaped, and welded so that the finished fitting shall have the re quired shape and interior dimensions. The deflection angle between adjacent segments of a bend shall be no greater than 22V deg. Adjacent segments shall he joined by lap or butt welding. Fabrication and welding shall conform to the requirements of Sec. 3.5 of this standard. The welds shall be in spected, and the completed cylinder shall be tested for tightness by the dye penetrant method or other approved method, if specifically required by the purchaser. 4.3.2 Reinforcement. Wire fabric reinforcing shall be applied to the in terior and exterior surfaces of the fab ricated fitting. The reinforcement shall be 2 X 4-in. W1 welded-wire fabric, held in. from the surfaces of the steel plate. The members on the 2-in. spacing shall extend circum ferentially around the fitting, with ends overlapped 4 in. and tied together. Longitudinal splices shall be staggered. 4.3.3 Mortar. Steel plate fittings shall be lined with mortar at least J in. thick at adapter ends, or outlets, but under no conditions shall the lining be less than | in. thick. The exterior shall be coated with mortar at least 1 in. thick. The mortar shall contain no less than 1 part cement to 3 parts sand of a grading approved for the method of application used. 4.3.4 Curing. Mortar-lined and mortar-coated fittings in Sec. 4.5.3 shall be cured by water spraying, by steam, or bv curing compounds. The curing compounds shall meet the re quirements of "Liquid Membrane-- Forming Compounds for Curing Con crete'' (ASTM Designation C50`)i, Type II, white pigmented. Sec. 4.4--Curves, Bends, and Closures Long radius curves and small ang ular changes in pipe alignment shall be formed by deflecting joints, by straight pipe with beveled ends, by bevel adapters, or by a combination of them. Pipe ends may be beveled up CTD000471 u CON'CRETE PIPE--XOT PRESTRESSED to 5 deg. Short-radius curves and closures shall be formed by fittings. Sec. 4.5--Openings and Connections Manholes and flanges, spigot or bell connections for air valves, blow olifs, or connections to other pipe shall be built into the walls of the concrete pipe at locations shown on the purchaser's drawings or ordered by the purchaser. Wail openings shall be suitably rein forced. If required, the interior and exterior surfaces of structural steel con nections shall be lined and coated with mortar. Appendix A Design Requirements This appendix is for information and is not a part of AlPIVA C300-T4. A1--General A3--Combined Load Design Reinforced concrete cylinder pipe covered by this standard shall be de signed by the method described herein to resist the internal pressures and ex ternal loads designated by the pur chaser. A2--Hydrostatic Design To resist internal pressure alone, the cross-sectional area of the circumferen tial steel reinforcement shall be no less than the maximum determined from equations (1) and (2): 6 PwD,j A> ~ 12,500 (1) 6(P,,. T P11D,, 16A00 (2! . L = C ross-sectional area of circum ferential steel reinforcement, including the steel cylinder, square inches per foot of pipe wall P,, - Working pressure, psi P, = Transient pressure, psi P.j = Inside diameter of steel c\Un der, inches The pipe shall be designed to resist the flexural and axial stresses from each of the following load conditions: 1. A combination of working pres sure, transient pressure, and dead loads (earth, pipe, and water) 2. A combination of working pres sure, dead loads, and live loads 3. Dead loads and live loads with no internal pressure. External dead loads and live loads shall be computed in accordance with recognized and accepted theories, such as presented in Soil Engineering by M. G. Spangler [International Text book Co., Scranton, Pa. (2nd ed., 1960), pp. 396-418] and in Con crete Pipe Design Manual [American Concrete Pipe Assn., Arlington, Va., (1970)]. The coefficients for moment and thrust shall also be from recognized and accepted theories, such as presented in "Stress Coefficients for Large Hori zontal Pipes" by J. M. Paris [Engi neering A'eics-Rccord, vol. 86, p. 768 (1921)] and in "Stress Analysis of Concrete Pipe" by H. C. Olander [Eng. Monograph No. 6, US Bureau CTD000472 APPENDIX A 15 of Reclamation, Dept, of the Interior, Washington, D.C.j. The bedding angle used in design shall be compatible with the installation specified by the purchaser. The reinforced concrete design shall be according to the applicable provi sions of ACI Standard 318, with either the strength method or the alternate design method (working stress method) being used. For the strength method, the load factor shall be 1.8; the capacity reduc tion factor, <j>, shall be 1.0; and an equivalent rectangular concrete stress distribution shall be used. The design yield strength, shall not exceed 40,000 psi for the sides of the pipe, and the design yield strength shall not ex ceed the value determined by equations (3a) or (3b) for the crown and invert of the pipe. f,ji = 27,000 psi, where A r < j {A r + A ,,) (3a) f,ji -- 33,000 psi, where Ar ^ \(Ar + A,j) (3b) fUi = Design yield strength for the crown and invert of the pipe, psi Ar = Cross-sectional area of rod rein forcement in the tensile zone of the crown and invert, square inches per foot of pipe wall Ay = Cross-sectional area of steel cylinder, square inches per foot of pipe wall For the alternate design method, the load and factors shall each be 1.0; the calculated compressive stress in the concrete shall not exceed 0.45 /,,' (the specified 28-day compressive strength) ; and the allowable tensile stress in the reinforcement shall not ex ceed 22.000 psi at the sides of the pipe and shall not exceed the value deter mined by equation (4) for the crown and invert of the pipe, with the appli cable value of f,,i from (3a) or (3b) being used. = 0.55/tfi (4) /,, = Allowable tensile stress for the inner layer of steel reinforce ment at the crown and invert, psi When the transient pressure is com bined with other loads, the required capacity for the strength method shall be reduced by 25 per cent, or allowable stresses for the alternate method shall be increased by one third. The pro visions of this paragraph apply only to load condition 1. A4--Reinforcement Cage Configurations Reinforcement shall consist of a steel cylinder and one or more cages. The cages may be circular or elliptical in shape and may be used singly or in combination. The cross-sectional area of the circumferential rod reinforce ment per linear foot of pipe shall be no less than 40 per cent of the total area of reinforcement per linear foot of pipe. When the reinforcement consists of a combination containing an elliptical cage, the cross-sectional area of the circular reinforcement, including the steel cylinder, shall be no less than that determined by Eq (1), with an allow able steel stress of 25,000 psi. The design depth of the pipe wall section shall be taken to the centroid of the tensile steel. The design clear con crete cover for an outer circular cage or for the horizontal axis of an elliptical cage shall be 1-J in. For the steel cyl inder, the design clear cover shall be the nominal lining thickness designated by the manufacturer but no less than the minimum lining thickness shown in Table 3 of Sec. 3.1.3. CTD000473 -13300 CTD000474