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784

  1. 1. IS 784:2001 c n . n (h WIciwf — Ilw ) Indian Standard PRESTRESSED CONCRETE PIPES (INCLUDING SPECIALS) — SPECIFICATION (Second Revision ) ICS 23.040,50; 91.100.30 0 BIS 2001 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002Februaty 2001 Price Group 10
  2. 2. Cement Matrix Products Sectional Committee, CED 53FOREWORDThis Indian Standard (Second Revision) was adopted by the Bureau of Indian Standards, after the draft finalizedby the Cement Matrix Products Sectional Committee had been approved by the Civil Engineering DivisionCouncil.This standard was published in 1959 and subsequently revised in 1978 to introduce prestressed concrete cylinderpipes, requirements of fittings, provision of more details on design criteria for the pipes, etc.This standard lays down the requirements of prestressed concrete pipes primarily used for the conveyance ofwater and sewerage and specials for use with them. Two types of prestressed concrete pipes are covered by thisspecification, namely, prestressed concrete cylinder pipes and prestressed concrete non-cylinder pipes,This second revision incorporates number of modifications, the most significant of them being: a) modifications in design and other aspects, b) inclusion of typical worked out examples of design, c) inclusion of detailed inspection procedure, and d) increase in range of diameters of pipes.In the formulation of this standard, assistance has been derived for EN 642:1994 Prestressed Concrete PressurePipes, Cylinder and Non-Cylinder, European Committee for Standardization (CEN).The composition of the technical committee responsible for formulation of this standard is given at Annex K.For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance withIS 2:1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in therounded off value should be the same as that of the specified value in this standard.
  3. 3. IS 784:2001 Indian Standard PRESTRESSED CONCRETE PIPES (INCLUDING SPECIALS) — SPECIFICATION (Second Revision )1 SCOPE 3.5 Site Test Pressure — 1.5 times working pressure pertaining to the section or 1,1 times static pressure,This standard covers the requirements of prestressed whichever is more (surge pressure is to be controlledconcrete pipes (including specials) with nominal within 25 percent of pump head in case of pumpinginternal diameter in the range of 200 mm to 2500 main).mm (see Note under Table 1), in which permanentinternal stresses are deliberately introduced by 3.6 Factory Test Pressuretensioned steel to the desired degree to counteract thestresses caused in pipe under service. a) Site test pressure + 0.1 N/mmz, for working pressure upto 1 N/mmz, and2 REFERENCES b) Site test pressure + 0.2 N/mmz, for workingThe standards listed in Annex A contain provisions pressure above 1 N/mm* .which through reference in this text constitute 3.7 Surge (Water Hammer) Pressureprovisions of this standard. At the time of publication,the editions indicated were valid. All standards are It is a pressure which is produced by a change ofsubject to revision and parties to agreement based on velocity of the moving stream and becomes maximumthis standard are encouraged to investigate the when there is sudden stoppage which may be causedpossibility of applying the most recent edition of the by the closing of a valve or by shutting down a pumpstandards indicated in Annex A. station. Surge pressure is to be controlled within 25 percent of pump head.3 TERMINOLOGYFor the purpose of this standard, the following 4 MATERIALSdefinitions shall apply. 4.1 Cement3.1 Prestressed Concrete CyIinder Pipe — A welded The cement used in the manufacture of prestressedsheet steel cylinder with steel socket and spigot rings concrete pipes and specials shall be one of thewelded to its ends, lined with concrete suitably following:compacted and circumferentially prestressed towithstand internal pressure and external design loads a) 43 grade ordhmry Portland cement conformingand subsequently coated with cement mortar or to IS 8112.concrete to protect the steel cylinder and prestressing b) 53 grade ordinary Portland cement conformingwires. to IS 12269, c) Rapid hardening Portland cement conforming3.2 Prestressed Concrete Non-Cylinder Pipe — A to IS 8041.suitably compacted concrete core longitudinallyprestressed with pretensioned high tensile steel wire d) Portland slag cement conforming to IS 455 withembedded in the concrete, circumferentially pre- slag not more than 50 percent.stressed and coated with cement mortar or concrete to e) Sulphate resisting Portland cement conformingprotect the circumferential prestressing wire, to to IS 12330.withstand internal pressure and external design loads. NOTE — Sulphate misting Portland cement shsll be used where sulphate is predominant.3.3 Specials — All items in the pipeline other thanstraight pipes of standard length, such as bendi, air 4.2 Aggregatesvalves and scour valve tees, etc, are classified asspecials. The aggregates shall conform to IS 383. The provision of4 (Grading) of IS 383 shall not apply. Manufacturer3.4 Working Pressure — The maximum sustained shall furnish the grading curve for coarse and fineinternal pressure excluding surge to which each aggregates which he proposes to use. The variation inportion of the pipeline maybe subjected when installed. fineness modulus during manufacture shall not be 1
  4. 4. IS 784:2001more than +5 percent. Silt content in fine aggregates Following composition of natural rubber is recom-shall be less than 3 percent. The fineness modulus of mended for sealing rings:the aggregates for coating shall be between 2.6 to 3.2. Natural rubber content 75.0 percent by mass, A4in4.3 Water as compound Ash 6.0 percent by mass, MaxWater used for concrete, cement mortar and for cur-ing the pipes shall be free from injurious amounts of Total sulphur 3.0 percent by mass, Maxoil, acid, strong alkaline scales and vegetable matter Acetone extract 8.0 percent by mass, Maxand shall be able to make concrete of satisfactory Sulphur in acetone 0.6 percent by mass, Maxstrength requirements. extract Alcohol potash extract 1.5 percent by mass, Ma4.4 Admixtures Filler Carbon black onlyAdmixtures may be used with the approval of the pur- Accelerators As requiredchaser. However, use of any admixture containing The compounding ingredients listed below shall bechlorides in any form shall be prohibited. Theadmixtures shall conform to IS 9103. added to the composition in the proportions (given based on 100 parts by mass of raw rubber):4.5 Steel for Reinforcement Waxes (melting point 0.5 parts by mass, Min4.5.1 Prestressing Steel 57° C Min) 1.5 parts by mass, MaxPrestressing steel wire shall conform to IS 1785 Napthenic process oil 2.5 parts by mass, Max(Part 1) or IS 1785 (Part 2) or IS 6003 or IS 6006. Anti-oxidant 1.5 parts by mass, MinFor longitudinal prestressing, wire having tensile 4.8 Bitumen or Other Protective Coatingstrength, less upto 15 percent of ultimate tensilestrength, may be used, if required. This is to avoid The purchaser may specify the application of anexcessive wear of rollers for threading, or cracking of external or internal bituminous epoxy or otherwire during button heading for end anchors. approved coating to be applied. When the pipes are to4.5.2 Unpensioned Reinforcement be used for carrying potable water, the inside coating shall not contain any constituents soluble in such waterUnpensioned reinforcement may consist of mild steel or any ingredient which could impart any taste orconforming to IS 432 (Part 1) or IS 432 (Part 2) or odour to the potable water.high strength deformed bars conforming to IS 1786or plain hard drawn steel wire conforming to IS 1785 5 DIMENSIONS AND TOLERANCES(Part 1) and IS 1785(Part 2) or welded wire fabricconforming to IS 1566. 5.1 Nominal internal diameter of the pipes and mini- mum core thickness shall be as given in Table 14.6 Steel for Cylinders and Specials 5.2 LengthSteel plates for cylinders and specials shall conformto IS 2062. Effective length of pipes shall be 2 m to 6 m. How- ever, the preferred effective lengths should be 2,2.5,4.7 Rubber Sealing Rings 4, 5 and 6 m. For pipes upto and including 300 mm4.7.1 Rubber sealing rings shall comply with IS 5382. diameter, the effective length shall not be moreThe manufacturer of pipe shall examine each sealing than 3 m.ring visually for defects, particularly at the joints. 5.3 Tolerance4.7.2 Every sealing ring shall be clearly marked. The 5.3.1 Lengthmarking shall indicate the chord diameter, internaldiameter of the ring and name of the manufacturer of Tolerance on length shall be *1 percent of the specifiedrubber sealing rings. length.4.7.3 In case of splices, each splice shall be thoroughly 5.3.2 Internal Diametervisually checked by twisting the ring through 360°.Splices showing visible separation or cracks shall be For pipes of length less than 4 m, the tolerance shallrejected. Not more than two splices in each ring shall be *5 mm for diameter upto and including 350 mm.be permitted. All sealing rings shall be protectt?d from For diameter above 350 mm, the tolerance shall bedirect rays of the sun and stored in dry place. *IO mm. 2
  5. 5. IS 784:2001For pipes of length 4 m and above, the tolerance shall diameters shall be furnished by the manufacturer forbe as given below: inspection. The indicative dimensions of socket and spigot are given in Annex B.Internal Diameter Tolerances A % 7 DESIGN / In areas within Over rest 7.1 Information to be supplied by purchaser is given 600 mm c)fan of the pipe in Annex C. end of the pipe 7.2 All pipes shall be designed to withstand the com- mm mm bined effects of internal water pressure and external loads.Up to 900 mm *6 *9 7.3 The design of the prestressed concrete pipes shallOver 900 mm and +9 * 12 cover all such stages, which may induce stresses in upto 1 600 mm any section of the pipe. For investigation of these de-Over 1600 mm + 12 + 12 sign stages, the likely extreme conditions of stresses shall be considered in the order of their occurrence, Table 1 Nominal Internal Diameter and during the process of manufacture, handling, erection Minimum Core Thickness of Pipes and under service. (Clause 5.1) 7.4 Design Criteria for Non-Cylinder PressureNominal Internal Minimum Nomianl Internal Minimum Pipes Diameter of Core Diameter Core Pipe Thickness of Pipe Thickness The pipes shall be designed to meet the requirements mm mm mm mm given in subsequent clauses. (1) (2) (3) (4) 7.4.1 Longitudinal Prestressing Requirements 200 35 1300 75 250 35 1400 75 The permissible stresses for various load combinations 300 35 1500 80 shall be as follows: 350 35 1600 85 Description of Loading Permissible Stresses 400 35 1700 90 Combination 450 35 1800 95 500 35 1900 100 Tension Compression 600 40 2000 105 N/mm* N/mm* 700 40 2100 110 a) Longitudinal — Minimum 800 45 2200 115 prestress (after residual 900 55 2300 120 losses) in barrel compression of 1000 60 2400 125 1 100 65 2500 130 2.5 N/mm* for 1200 70 upto and inclu- ding pipe dia NOTES 600 mm and I Internal diameter of pipes other than those mentioned in this table may be suppliedby mutualagreementbetween the purchaser 1.0 N/mmz for and the manufacturer.For higherpressure the core thickness have dia above to be increase~ in such cases: 600 mm. a) the diameter will be correspondingly reduced (This is to b) Longitudinal 0.56fi0s o.5~ enable use of same moulds), and prestress during b) multiple layers of circumferential prestressing wire shall be circumferential adopted. prestressing 2 This standardincludesprovisionupto 2500 mm diameterpipes. Pipes of diameter beyond 2500 mm maybe supplied in special (temporary) cases by mutual agreement between purchaser and manufacturer c) Longitudinal ().34fik0”5 0.5 fik subject to additional precautions taken in design, manufacture, prestress after testing and construction of the pipe. losses plus beam5.3.3 Core Thickness action d) Handling 0.67 N/mmz 0.5fiThe core thickness shall not be less than the design e) Transport and ().56 fik0”5 O. S&kthickness by more than 5 percent. The manufacturer unloadingshall declare the core thickness and the above toleranceshall be applicable to that core thickness. Characteristic compressive strength of6 JOINT DIMENSIONS concrete at p days in N/mm*, andJoint dimensions with tolerances for socket and spigot Characteristic compressive design strength of concrete in N/mm*. 3
  6. 6. IS 784:2001 NOTES Description of Loading Permissible Stresses 1 Longitudinal stresses induced in the core during circumferen- tial prestressing shall be treated as temporary and shall be equal Combination / . to 0.284 times initial compressive stress induced in core. Tension Compression 2 Forlongitudinal tressdue to beam action, a pipe shall be s N/mm2 N/mm2 assumed to span its full Iengtb and suppost a total load per meter in Newtons equal to the self weight, the weight of the water in the e) Operating con- 0.13 fik0”67 0.45 &k pipe and earth load equivalent to 2.2 times the outside diameter dition + Live load of pipe (in r@. 3 For calculation of number of Iongitudinalsfor tnmsport and un- (with impact) loadingconditiorw followingbendingmoment shallbe considered foreffectivelengthofpipcs upto 5mcterand dismctcrupto600mrw where Dia Bending Moment f, = Characteristic compressive strength of mm Nmm concrete at p days in N/mm2. 200 3.04X 10’ 250 3.78 x 107 Characteristic compressive design strength 300 4.59 XI07 of concrete in Nhnm2. 350 5.45 x 10’ NOTES 400 6.37 x 107 450 7.36 X 107 1 The total tensile stress in the core shall be consideredas the sum 500 8.44 X107 of the hoop stress and flexrmdstresses, without the application of 600 11.08 xIt)’ any reduction factor. Forp@cs havingeffectivelengthmorethan5 w thebendingmoment 2 When calculating hoop stress, only core thickness should be shall be multipliedby a factor(L/5~, whereL is the effectivelength cmrsidemd. When calculating ovalization flexw.alstress,the sum of pipe. Forpipesabove600 mm diameter,no specialconsideration of the core and coating thickness should be considered. is necessary,The minimum number of Iongitudinalsfor4 m and 5 3 For calculating bending moments and thrusts forextemal loads, m long pipes shall be 12and 16respectively. Olandm’scoefficientsareto be used.The valuesforbidding angles from 30” to 180° are given in AnnexE.7.4.2 Typical calculation for the design of longitudinal 4 When submitted to factory test, the mortar or concrete coatedfor pipe diameter 600 mm and below is given in pipe shall not have cracks in the coating wider than 0.1 mm forAnnex D. more than 300 mm length.7.4.3 Circumferential Prestressing Requirements 7.5 Loss of prestress in circumferential and longi-The permissible stresses for various load combinations tudinal wires shall be calculated as per Annex F.shall be as given below: 7.6 Typical design of prestressed concrete pipe, withDescr@tion of Loading Permissible Stresses winding by process of counter weightheak is given Combination e A . in Annex G. Tension Compression N/mm2 N/mm2 ‘7.7 Typical design of prestressed concrete pipe witha) Circumferential o o.55~ winding by process of die is given in Annex H. prestressing 7.8 Typical design of prestressed concrete pipe for condition drainage, sewerage and culverts is given in Annex J. (Self weight + Initial prestress) 7.9 Design Criteria for Cylinder Pipesb) Site test condition 0.13 jkO’67 ().45&k The pipes shall be designed to meet the following con- (Site test pressure + ditions: Self weight + Weight of water + Permissible Stresses Description of Loading Earth fill + Final Combination prestress) Tension Compressionc) Factory test con- 0.13 $k0”67 0.45 ~k N/mm2 N/mm2 dition a) Circumferential o 0.55 & (Factory test prestressing pressure + Self condition weight + Weight of (Self weight + water + Pre-stress at Initial prestress) factory test) b) Site test condition 0.38 fik0”67 o.45fikd) Operating condition O ().45fik (Site test pressure + (Working pressure+ Self weight + Self weight + Weight of water+ Weight of water + Earth fill + Final Earth fill + final prestress) prestress) 4
  7. 7. IS 784:2001Description of Loading Permissible Stresses that concrete will be evenly distributed. The same is Combination > sufficiently compacted at the specified thickness Tension Compression throughout the length of the pipe. After the concrete N/mm* N/mmz has been deposited, the rotation shall be continued at an increased speed, for a length of time sufficient to c) Operating condition o o.45fik provide the specified strength, sufficient compaction (Working pressure+ Self weight + and bond; to permit handling of the mould from the Weight of water + spinning machine, without damage to the pipe core. Earth fill + Final Excess water and laitance shall be removed from the prestress) interior surface of the pipe in an approved manner so that the surface is solid, straight and true. d) Operating condi- o.38jk0”67 ().45&k tion + Live load 8.2 Curing of Core and Cover Coat (with impact) The curing of the concrete core and that of cover coat where shall be in two separate operations. The curing for f. r = Characteristic commessive strength of core shall be for a period, till it attains the required concrete at p days in N/mmz. strength. (k = Characteristic compressive design strength of concrete in N/mrn2. Curing shall be either by steam or by water or by a combination of steam and water, or by use of approved8 MANUFACTURE curing compounds. Coating shall be cured for a minimum period of 7 days, if water curing is used. If8.1 Core steam curing is used for coating, after that it should8.1.1 Moulds be water cured for at least 3 days.The moulds and method of manufacture of pipe shall 8.3 Pretensioning and Release of Longitudinalbe such that the form and dimensions of the finished Wirespipe conform to the requirements given in 5 and 12and the surface and edges are clean and true. The concrete core shall be longitudinally prestressed, including the socket, by means of high tensile steel8,1.2 Concrete Mix wires or strands, which shall be provided withThe proportions of cement, fine aggregate, coarse permanent anchorages embedded in the concrete,aggregate and water used in concrete for pipe core shall within the joint portion at each end. The centrelinebe determined and controlled as the work proceeds to spacing between the longitudinal wires measuredobtain homogeneous,dense, workable, durable concrete along the barrel shall not exceed twice the coreof specified strength in the pipe, and minimum defects thickness or 150 mm, whichever is greater, subject toon the surface of the pipe. The proportions shall be the provision of 7.4.1(c).those, that will give the best overall results with the The clear cover of concrete overall steel reinforcementparticular materials and the methods of placing used including the ends of the longitudinal prestressingfor the work. A minimum of 350 kg/m3 of cement shall wires, shall be such that in any finished pipe it isbe used for concrete. The water cement ratio shall be nowhere less than 12 mm.such, as to ensure that the concrete will meet the strengthrequirements, but in no case it shall exceed 0.5. The 8.3.1 The longitudinal wires shall be stressed to thesoluble chloride ion content of the concrete or mortar designed tension, taking into account the loss of stressmix, expressed as a percentage of the mass of cement in wire. The tension shall be maintained by positiveshall not exceed 0.20 percent. means till detensioning.Unless the design calls for higher concrete strength, 8.3.2 The tensioned wires shall not be released untilthe minimum compressive strength of concrite shall the concrete in the core has attained a compressivenot be less than 40 N/mmz at 28 days. strength of at least two times the initial longitudinal prestress or 15 N/mm2 whichever is greater.8.1.3 Placing of Concrete 8.4 Circumferential PrestressingThe concrete in the cores maybe placed either by thecentrifugal method, vertical casting method, or by 8.4.1 Circumferential prestressing shall not take placeother approved methods. For centrifugal spinning until the concrete in the core has reached a minimummethod, concrete shall be deposited in the mould and compressive strength of 25 N/mm2, or as per the designthe speed of rotation during placing shall be such, requirements whichever is greater. 5
  8. 8. IS 784:20018.4.2 The initial stress in the wire during circum- 8.5.3 Pneumatic process in which mixing of ingredi-ferential winding shall not bemorethan 75 percent ents is carried out at the nozzle or gun, shall not beof the minimum ul’timatetensile strength of wire, when permitted.counter-weight or break system is used for develop- 8.5.4 The compressive strength of the cover coatinging tension. If tension is developed by use of a die, mortar shall be obtained from cubes having area ofthen the initial stress in the wire shall not exceed 65 face 50 cmz or the compressive strength of the coverpercent of the ultimate tensile strength of wire. coating concrete shall be obtained from cube having8.4.3 The initial compressive stress induced in the core area of face 100 cm2 and shall not be less thanconcrete shall not exceed 55 percent of the compressive 35 N/mmz at the time of factory testing of pipe.strength of the concrete in the pipe at the time of tmnsfkr. 8.5.5 The mortar coating shall have a minimum cover8.4.4 Methods and equipments for wrapping the wire of 18 mm and concrete coating shall have a minimumshall be such that wire shall be wound around the core cover of 25 mm, over all steel, except at end face andin a helical form at the predetermined design spacing the spigot portion going inside socket, where it willand capable of controlling the tension. Wire splicing be not less than 15 mm. To achieve adequate bondshall be capable of withstanding a force equal to the between core and coat, approved bonding agent shallfull strength of wire. At the ends of core pipe, the be applied, at ends of pipe for a width of 100 mm,wire shall continue for at least one extra circumferential along the circumference to prevent separation betweenturn before being anchored. core and coat, at ends.8.4.5 The clear spacing between the successive turns Concurrently with the mortar coating, a cement slurryof the circumferential prestressing wires shall be not shall be applied on to the core at a rate of not less thanless than 6 mm, except at ends or at joints and shall 0.5 l/m2 just ahead of the mortar coating. The slurrybe not more than 50 mm. shall consist of 1.2 kg of cement to per Iitre of water.8.4.6 Test Cube Conversion Factors 8.5.6 The thickness shall be checked for every pipe as soon as, coating is done.The core concrete compressive strength shall be takenon 150 mm x 150 mm cubes. Where the process of 8.5.7 Mortar Soundnessmanufacture is such that the strength of concrete in After the mortar coating is cured and prior to transport,the pipe differs from that given by tests on vibrated the coating on each pipe shall be checked forcubes, the two may be related by suitable conversion delamination and hollows by tapping the exterior withfactors. If the purchaser requires evidence of these a hammer having a head mass of not more thanfactors, he shall ask for it, before placing the order. 0.5 kg. Any hollows or drumming areas detected byThe core concrete strength shall be obtained by sounding shall be repaired by approved methods.multiplying the cube strength with the conversionfactor and shall be used for design purpose. 8.5.8 All cement coming in contact with each other shall be of same type and composition and shall be8.5 Cover Coating from the same cement works.8.5.1 The circumferential prestressing wires on the 9 ADDITIONAL REQUIREMENTS FORcore pipes shall be protected with a layer of rich cement CYLINDER PIPESmortar or concrete or any other approved material 9.1 The prestressed concrete cylinder pipes shall bewhich prevents corrosion of wire. manufactured to comply with the following additional8.5.2 If cement mortar is used for cover coating, it requirements.shall be applied by rotary brushes or by other approved 9.1.1 Steel Socket and Spigot Ringsmethods and shall preferably be applied within 16hours after the prestressing wire is wound. The cement, Each ring shall be formed by one piece of steel or asand and water shall be thoroughly mixed, before being number of pieces of steel butt-welded together. Thefed into the cover coating machine. Minimum cement rings shall be expanded beyond their elastic limit socontent in coating mortar shall be 540 kg/m3 and that that they are accurately shaped. The portion of thefor concrete 500 kglm3. Water cement ratio in the mix socket and spigot rings which shall be exposed aflershall not be less than 0.27, if cement mortar is used the pipe is completed shall be smooth to prevent cuttingfor coating. Rebound or droppings not exceeding one of the rubber gasket during jointing and shall befourth of the total mass of mix, may be used but the protected from corrosion by a sprayed zinc coating ofresulting mix proportions shall not be, leaner than minimum thickness of 0.05 mm followed by one coatoriginal design mix. Rebound not used within one of bituminous paint. Other suitable protection maybehour, shall be discarded. used with the approval of the purchaser. 6
  9. 9. IS 784:20019.1.2 Fabrication of Steel Cylinders sealing ring, the joint shall be self centreing, flexibleThe cyiinder shall be accurately shaped to the size and water tight. The joint shall be roll-on or confinedrequired and steel socket and spigot rings welded type. Sockets of the pipes maybe projecting or flushthereto after being jigged square with the longitudi- with the barrel. Joint design shall be furnished bynal axis (except for bevel). manufacturer before undertaking manufacture. The9.1.2.1 Testing rubber ring joint design, shall take into consideration the tolerance for rubber chor~ tolerance for socketBefore it is subjected to any further manufacturing and spigot diameters, allowable deflection at joint andprocess, each steel cylinder, with steel and spigot rings permanent set in the rubber ring.welded on, shall be subjected to water pressure whichstresses the steel to at least 140 N/mm2, but not more 11.2 The sealing rings shall be of such size that whenthan 175 N/mm2. While under stress, the assembly jointed, in accordance with the manufacturer’s instruc-especially welds, shall be inspected and any parts tions, it shall provide a positive seal within the manu-showing leakage shall be repaired and the whole as- facturer’s recommended range of maximum joint de-sembly retested. flection. Not more than two splices in each ring shall be permitted.10 SPECIALS10.1 Fabrication 12 WORKMANSHIP AND FINISHThe steel for fabricated steel plate specials, is cut, 12.1 Deviation from the Straightnessshaped and welded so that the finished special has therequired shape and internal dimensions. Adjacent seg- When measured by means of a one metre straight edgements are jointed by butt welding. Before lining and the deviation from straight per metre length shall notcoating, the welding of specials shall be tested by use exceed 5 mm.of hot oil or dye penetrant according to IS 3658 and 12.2 Finishdefects, if any shall be rectified. The steel plate thick-ness for specials shall be as given in IS 1916. Pipe shall be free from local depressions or bulgesIn die penetration test, a white wash is applied over greater than 5 mm extending over a length, in anythe weld on one side of the cylinder; on other side direction, greater than twice the thickness of barrel.when coloured paraffin or similar product is applied The external surface of the pipe may be sand faced,over the weld, no coloured spot shall appear on the when coating of cement mortar is applied.whitewash before 4 h. If any coloured spots appear 13 TESTbefore 4 h, weld shall be repaired and retested. 13.1 Design Proving and Manufacturing Process10.2 Lining and Coating Approval Test in FactorySteel plate specials are lined and coated with concreteor cement mortar or other approved materials, as As Won os 4 to 5 pipes are made, these shall be in-agreed between the manufacturer and the purchaser. stalled and site pressure test shall be conducted, to proveThe proportion of cement to total aggregate shall not and finalize pipe and joint design and joint dimensionbe leaner than 1:3 by mass. tolerances, etc. For one diameter and different pres- sure, only the test for highest pressure shall be done.10.3 Reinforcement For this test no external load shall applied.For concrete or cement mortar coating, reinforcementshall be suitably tack welded to the shell. The rein- 13.2 Hydrostatic Factory Testforcement shall be wire rods and spirals or wire mesh The pipe shall be tested in accordance with IS 3597.or wire fabric. The pipe must not show leakage. Damp or wet patches10.4 Jointing Between Special and Pipe shall be accepted. If the pipe fails to pass the test, itThe special shall be jointed to the pipe by same ro- can be cured or repaired to improve its water tight-bberring joint as for pipes or by caulking with mortar. ness and then retested. In case the pipe does not standFor this purpose steel collars shall be welded to steel the rated internal pressure, it shall be accepted forspecials to allow caulking of joint with mortar. This lower pressure, purchaser at his own discretion mayis allowed only upto working pressure of 3 kg/cm2. accept the pipes for lower pressure to which it with- stands, provided all other requirements are conform-11 JOINTS ing to this standard.11.1 Unless specified otherwise, jointa between pipesshall be of the spigot and socket type, so manufac- Non-pressure pipes for drainage, sewerage and cul-tured, that when fitted with the correct $ize rubber verts, shall be tested for 0.14 N/mm2. 7
  10. 10. IS 784:200113.3 Permeability Test on Coating 13.6 Repair of Core and CoatThe drop of water level, in the specimens of pipes se- Pipes not satisfying any of the tests, which may belected, when tested according to the method described arising due to occasional imperfection in manufac-in IS 3597 shall not exceed 2 cm3 at the end of two ture or damages during handling, may be treated /hours and the final permeability between fourth and repaired and shall be accepted if they satis~ the tests.fifth hour shall not exceed 0.3 cm3. When a higher re- The curing of the repaired concrete or mortar maybesult is obtained, the test shall be repeated on twice the done using curing compound.number of pipes originally tested and the lot shall be 14 SAMPLING AND CRITERIA FORaccepted, if all pipes pass the test. Where retest is not ACCEPTANCEsatisfactory, all pipes from that lot may be tested indi-vidually and only those with satisfactory results shall 14.1 Pressure Pipes for Water Supply and Seweragebe accepted. No additional treatment of any type shall Basic requirement, unless the design proving andbe allowed on the pipe before permeability testis done. manufacturing process test in 13.1 is satisfactorilyThe criteria for acceptance is the final permeability. carried out, no acceptance tests shall be undertaken.The test shall be done immediately after the This has to be done for every new diameter of pipehydrostatic factory test. In case this is done later, the and for one pressure.pipe shall be kept wet for 48 hours prior to test. All the pipes manufactured under relatively similar13.4 Three Edge Bearing Test (for Pipes for Drain- conditions in respect of raw-materials and processingage, Sewerage and Culverts) operation, shall be grouped together to constitute a lot.Pipes designed for drainage, sewerage and culverts when Each lot shall be taken separately for sampling andsubjected to three edge bearing test in accordance with evaluation, for conformity to the requirements of thisIS 3597 shall meet the requirement as given in Table 2. standard, if the conditions mentioned in 5.1, 5.2,5.3,13.5 Dimensional Characteristic 11.1, 11.2 and 12.2 are satisfied (even after repairs). Scale of sampling shall be as given in Table 3.The pipe selected shall be checked for conformity tothe dimensional requirements as given below: 14.2 For non pressure pipes for drainage, sewerage and culvert, only permeability test from Table 3 a) Socket and spigot diameters of the pipes as given besides dimensions and three edge load bearing test by manufacturer. is necessary. b) Dimensional requirements as given in 5. Table 2 Three Edge Bearing Test Loads for Pipes for Drainage, Sewerage and Culverts (Clause 13.4 ) Nominal Np2 Class Np3 Class Np4 Class I Nominal Np7 Class –- Np3 Class Np4 Class Internal Dia Load to Load to Load to Internal Dia Load to Load to Load to of Pipe Produce Produce Produce of Pipe Produce Produce Produce Maximum Maximum Maximum Maximum Maximum 0.25mm 0.25 mm 0.25 mm 0.25 mm 0.25 mm 0.25 mm Crack Crack Crack Crack Crack Crack mm kNlm kN/m kN/m mm kN/m kN/m kN/m (1) (2) (3) (4) (1) (2) (3) (4) 200 11.77 14.50 24.60 1300 28.20 62.30 96.20 250 12.55 15.00 25.50 1400 29.42 67.06 104.20 300 13.48 15.50 26.40 1500 30.77 71.85 111.90 350 14.46 16.77 29.80 1600 32.12 76.64 119.60 400 I5.45 19.16 33.90 1700 33.59 81.40 127.40 450 16.18 21.56 36.90 1800 35.06 86.22 135.30 500 17.16 23.95 40.00 1900 36.41 91.00 135.30 600 18.88 28.74 46.30 2000 37.76 95.80 135.30 700 20.35 33.53 52.20 2100 38.99 100.60 138.70 800 21.57 38.32 59.30 2200 40.21 105.38 142.20 900 22.80 43.11 66.30 2300 — 110.00 148.60 1000 24.27 47.90 72.60 2400 — 114.96 155.00 1 100 25.50 52.69 80.40 2500 — I 19.70 160.80 1200 26.97 57.48 88.30 NOTE — Pipes with other three-edge bearing test requirements maybe supplied by agreement between purchaser and manufacturer. 8
  11. 11. IS 784:2001 Table 3 Scale of Sampling and Number of Acceptable Defective Tests (Clause 14.1) Number Hydrostatic Socket and Permeability Coating Dimensional Three Edge of Pipes Test Spigot Thickness Test Bearfng Test in Lot Dimension Drainage, Sewerage, Culvert Pipes . r , > * ** * ** * ** * q * q q ** (1) (2) (3) (4) (5) (6) (7) (8) (9) (lo) (11) (12) (13) 20-50 All Nil All Nil 3 Nil 3 Nil 3 Nil 2 Nil 51-100 All Nil AH Nil 5 Nil 5 Nil 5 Nil 2 Nil 101-300 All Nil All Nil 8 Nil 8 Nil 8 Nil 3 Nil 30 I-500 All Nil All Nil 13 Nil 13 Nil 13 Nil 4 Nil 501-1000 All Nil AH Nil 26 1 26 1 26 1 5 Nil * Number of samples. ** Number of defective accemabie.14.3 After the lot is accepted, each pipe shall be 15.1.2 Core Thicknesstnarked with a colour band at ends. Different colours Measurement of outer circumference of core shall beto be used for different pressure heads. made at three barrel positions and average outer di-15 PROCEDURE FOR INSPECTION ameter of core shall be calculated. The inside diam- eter shall be measured at three barrel positions and15.1 Dimensional Checks average is calculated. The core thickness shall be cal-15.1.1 Internal Diameter culated as follows:The internal diameter shall be measured at each end Average outside diameter – Average inside diameterof the pipe at approximately 50 mm from the ends 2and at centre. Two measurements of the internaldiameter at 90° to each other shall be made at each 15.1.3 Socket and Spigot Diametersend and at the centre. 15.1.3.1 Socket diameter ~ointing surjace)To accomplish this, ‘Go’ and ‘No Go’ gauges of a The socket diameter shall be checked by measuringstiff rod with hardened rounded ends shall be used. the sway by touching the two points B and B, alongThe length of gauges and colour shall be given below: the circumference of socket (see Fig. 1); BB, gives Length Colour the sway. Gauges for ends Example: ‘Go’ 1 mm less than Green —ve tolerance Suppose the theoretical diameter of socket ‘No Go’ 1 mm more than Orange D =1383mm + ve tolerance Permissible variation =+2mrn Gauges for centre -0.5 mm ‘Go’ 1 mm less than – ve Green with The. maximum diameter = Dl = 1385 mm tolerance white bands The minimum diameter = Dz = 1382.5 mm ‘No Go’ 1 mm more than + ve Orange with The sway = S= 2 x [h x (D, – h)]05 tolerance white bands Assume h = 5 mm (see Fig. 1)Example: Sway S = 2 x [5 x (1385 – 5)]05 Suppose theoretical diameter of pipe= 1200 mm =2x83 and length of pipe 5 m. = 166 mm. Tolerance Length of gauge L2 = (S/2)2 + (D1 – h)2 Ends +9 ‘Go’ 1200– 8=l192mm = (166/2)2+(1 385- 5)2 = 6 889+ 1904400 ‘No Go’ 1 200+ 10= 1 210mm L = 1382.5 mm Centre * 12 ‘Go’ 1 200– 11 = 1189 mm This should not be more than the minimum ‘No Go’ 1 200+ 13 = 1213 mm permissible inside diameter. 9
  12. 12. IS 784:2001 SWAY- S F -1Therefore, in this case FIG. .- 1 ARRANGENIIN 1 1 7 1 L Gauge for Measuring Sway FOR MEASURING SWAY 15.1.4 Straighlne.r.s Length of gauge, L = 1382.5 mm The straightness shall be measured by a one metre Maximum permissible sway = 166 mm. long gauge . The deviation from straight line taken between two points one metre apart, along the pipe15.1.3.2 Spigot Diameter barrel shall not exceed 5 mm (see Fig. 3).The gauge as shown in Fig. 2 shall be used. 5mm f“ ~1Examp[e: ~ 1000 ~ Suppose the theoretical outside diameter of FIG. 3 GAUGE FOR MEASURING STRAIGHTNESS spigot = 1200 mm Permissible variation = + 1 mm 16 MARKING The maximum diameter = 1201 mm The minimum diameter = 1 199 mm. 16.1 The following information shall be clearly marked on each pipe:To enable gauge to pass over the spigot surface, thediameter must be more by 1 mm than the maximum a) Source of identification of the manufacturer,spigot diameter. b) Size and hydrostatic factory test pressure, andThe clearance between gauge points = 1 200+1 + 1 c) Date of manufacture. = 1202 mm. 16.2 Each pipe may also be marked with the StandardFor checking. spigot, the gauge is held in the position Mark.as shown in Fig. 2. Then by keeping point ‘X’ fixed,other end ‘Y’ of gauge is moved over the circumference 16.2.1 The use of the Standard Mark is governed byof spigot, where the gap between spigot surface and the provisions of Bureau oflndian Standards Act, 1986gauge is maximum, a strip 2.5 mm, thick and 25 mm and the Rules and Regulations made thereunder. Thewide (straight side) (1 201 – 1 199 = 2.0 mm) is in- details of conditions under which a licence for the useserted. It should not go. Two checks shall be done at of Standard Mark maybe granted to manufacturer and90° to each other. producers may be obtained from the Bureau of Indian Standards. STRIP 3.5 NOTTO GO ‘b .--p, ..e:.~.@. .;.8 u .e . “*. - ..4. . .,..:-... ‘, ./ ROLL ON JOINT CONFINED JOINT FIG. 2 ARRANGEMENT FOR CHECKING SPIGOT DIAMETER 10
  13. 13. IS 784:2001 ANNEX A (Clause 2) LIST OF REFERRED INDIAN STANDARDS IS No. Title IS No. Title432 Specification for mild steel and 1916: ]989 Specification for steel cylinder pipe medium tensile steel bars and hard- with concrete lining and coating drawn steel wire for concrete rein- (fkst revision) forcement 2062:1992 Steel for general structural purposes (Part 1) : 982 Part 1 Mild steel and medium tensile ~ourth revision) steel bars (third revision) 3597:1998 Methods of test for concrete pipes (Part 2) : 982 Part 2 Hard-drawn steel wire (third (second revision) revision) 3658:1999 Code of practice for liquid perma-455:1989 Specification for Portland slag nent flaw detection (second revision) cement ~ourth revision) 5382:1985 Rubber sealing rings for gas mains,783:1985 Code of practice for laying of water mains and sewers (@st concrete pipes (first revision) revision)1566:1982 Specification for hard-drawn steel 6003:1983 Specification for intended wire for wire fabric for concrete reinforce- prestressed concrete @st revision) ment (second revision) 6006:1983 Specification for uncoated stress1785 Specification for plain hard-drawn relieved strand for prestressed steel wire for prestressed concrete concrete ~rst revision) (Part 1) :1983 Part 1 Cold-drawn stress relieved 8041:1990 Specification for rapid hardening wire (second revision) Portland cement (second revision) (Part 2) :1983 Part 2 As drawn wire first revision) 8112:1989 Specification for 43 grade ordinary1786:1985 Specification for high strength Portland cement ~rst revision) deformed steel bars and wires for 9103:1999 Specification for admixtures for concrete reinforcement (third concrete (jrst revision) revision) 12269:1987 Specification for 53 grade ordinary Portland cement 11
  14. 14. Is 784:2001 ANNEX B (Clause 6) INDICATIVE DIMENSIONS OF SOCKET AND SPIGOT OF PRESTRESSED CONCRETE PIPE .. ...B-1 The indicative dimensions of socket and spigot of prestressed concrete pipe are given below (see also Fig. 4): ... ... ..... .. ..... ... .. - ...-::...,,.. w Qw ,4 . . . ...4 . . . . . ,.-. ~-. ,. !.4 ;.:”.: $. ’,,- -..*-......4, ,4. .4 .. .“. ;.,:, .9 . “ . . ,* .s-’.; a.. ..b. .*., ;’ .;. ‘a’. :. 8 .. “ !,” ~.. .’, - -t:@- .“ ... ,“ “:,.;*,”? ROLL ON JOINT CONFINED JOINT FIG. 4 DETAILS OF JOINTS A Roll On Joint Conjined Joint Nominai Dia of A . / — . Pipe c B ‘- c B Internal Dia of External Dia of Internal Dia of External Dia of Socket Spigot Socket Spigot 200 308 290 308 290 250 352 334 352 334 300 404 386 404 386 350 456 438 456 438 400 518 500 518 500 450 562 544 562 544 500 612 594 612 594 600 726.5 704 726.5 704 700 826.5 804 826.5 804 800 937.5 915 937.5 915 900 1058.5 1036 1058.5 1036 1000 1165.5 1141 1165.5 1141 1100 1270.5 1246 1270.5 1246 1200 1381.5 1357 1381.5 1337 1300 1496.5 1472 1496.5 1472 1400 1595.5 1571 1595.5 1571 1500 1706 1678 1706 1678 1600 1818 1790 1818 1790 1700 1928 1900 1928 1900 1800 2036 2008 2036 2008 1900 2154 2 126 2154 2126 2000 2264 2236 2264 2236 2100 2374 2346 2374 2346 2200 2488 2454.5 2488 2431.5 2300 2598 2564.5 2598 2564.5 2400 2708 2674.5 2708 2674.5 2500 2818 2784.5 2818 2784.5 NOTE — All the manufacturers shall try to achieve above dimensions within a period of five years. 12
  15. 15. IS 784:2001 ANNEX C (Clause 7.1) INFORMATION TO BE SUPPLIED BY PURCHASER WITH AN ENQUIRY OR ORDER FOR PRESTRESSED CONCRETE PIPESC-1 The following information shall be supplied: 1) The maximum and minimum depths of cover over the crown of the pipe. a) The type of cement to be used in the core and the cover coat (4.1); 2) The width of the trench at the crown of the pipe (normally outside diameter of pipe + b) Whether or not a bituminous or other approved 600 mm). If the pipes are to be laid above coating is required internally and ground in case of partial trench, full details externally (4.8); including L-section should be supplied. c) The maximum working pressure (3.4); 3) Whether more than one pipeline is to be laid d) 1he maximum sne test pressure 15.3J; in the trench and if so, what will be the trench width at the crown of the pipe. e) Factory test pressure (3.6); 4) Details of the backfill material, that is, sand, f-) Pressure in addition to (c) to which the pipe- gravel, etc. line will be subjected due to surge (water 5) Density of filling material. hammer) (3.7), if any; and 6) Type of bedding intended. g) Following pipe installation details: 7) Anticipated superimposed loading on ground surface. ANNEX D (Chse 7.4.2) TYPICAL CALCULATION FOR THE DESIGN OF LONGITUDINAL FOR PIPE DIAMETER 600 mm AND BELOWD-1 Explanation of various symbols used in subsequent Initial compressive stress = 10.6575 N/mm2clauses is given in Annex K. induced in core, fCi (Assumed)D-2 DATA D-3 CALCULATION OF STRESS IN Diameter of pipe, D = 500 mm LONGITUDINAL DIRECTION Effective length of pipe = 5000 mm D-3.1 Centreline Spacing Between Longitudinal Core thickness, tc =35mm Wires Coat thickness, $ =22mm Centreline spacing between longitudinal wires shallMinimum compressive strength of core concrete not exceed twice the core thickness or 150 mm(spun) at various stages whichever is greater (see 8.3), that is a) Characteristic compressive = 40 N/mm* 2 x 35 or 150 mm, that is, 150 mm. design strength, Number of longitudinal = 16 b) At winding (see 8.4.1),42 =25 N/mm2 considered in design c) At detensioning = 15 N/mm2 Centreline spacing = 3.1416 x (D + TC)/N longitudinal (see 8.3.2), ~P1 between longitudinal wires =3.141 6 x (500+35)/16, Diameter of longitudinal wire = 4 mm = 105.04 mm 150 mm Ultimate tensile strength = 1715 N/mm* Hence, number of longitudinal considered in design of wire (see 4.5.1) is correct. 13
  16. 16. IS 784:2001D-3.2 Intial Longitudinal Precompression in Core Precompression at 16x 12.57 x 1094.88 = winding, fCIW 58826.46Initial stress in longitudinal wire (see 8.4.2), ~il 1715 x 0.75 = 1286.25 N/mm* = 3.7422 N/mm2Area of core concrete, AC At site test 3.14~ 6 x 535 x 35 = 58826.46 mm2 Stress in longitudinal wire after losses,Longitudinal precompression ~1 = 1286.25-212.63 = 1073.62 N/mm2 Longitudinal force 16X 12.57 X 1073.62 . . N x ‘dl x ~il Final precompression, l = 58826.46 AC AC ~1 = 3.6705 N/mm2 16X 12.57 X 1286.25 Initial precompression, ~il = D-3.5 Longitudinal Stress Due to Circumferential 58826.46 Winding = 4.3975 N/mmz Maximum local longitudinal tensile stress duringConcrete strength required at detensioning of windinglongitudinal, ~1 (see 8.3.2) = 0.284 x 10.6575 = 3.0267 N/mm2 2 x ~il OR 15 N/mm2, whichever is greater, D-3.6 Stress Due to Beam Actionthat is, 2 x 4.3975 = 8.7950 or 15 N/mm2, which- Self weight of pipe W,= 2295.62 N/mever is greater Weight of water WW= 1963.50 N/m Adopt ~Pl= 15 N/mm2 Earth load to be considered (see 7.4.1)D-3.3 Loss of Stress in Longitudinal Wires (see 2.2x(D+2x Tc+2x Tb) = 1350.80 N/mAnnex F) = 2.2 X 614 a) Relaxation of wire Total load W= W, + WW+ 1 350.80=5 609.92 N/m 0.08 x j,il = 0.08 x 1286.25 = 102.90 N/mm* Modulus of circular section of pipe (Zl) b) Deformation due to creep 2.50 X~Cil 2.50 x 4.3975 = 10.99 N/mm2 = 3.1416 x 6144-5004 =12 731728mJ c) Deformation due to shrinkage 32 614 0.0001 x Es= 0.0001 x 20.0 x 104 Bending moment (BM) = 20.00 N/mm2 @ 5609.92 x5x5 xlo00 =17531000Nm d) Yield due to mould shortening, wire stretch due —= to filling, vibration during spinning, etc 8 8 2xE. BA4 —=l.3769N/mm2 Effective length of pipe + 80 mm ‘tiess ‘Ue ‘0 bem action = z, D-3.7 Stress Due to Self Weight of Core 2X20 X104 = 78.74 N/mm* = 5000+80 Self weight of core ( WC)= 1411.84 N/m Modulus of circular section of core (Z2) Total losses = 102.90+ 10.99+ 20.0+ 78.74 = 212.63 N/mm2 3.1416 ~ 5704-5004 =7416520m3D-3.4 Precompression in Core in Longitudinal 32 570Direction B.M. due to mass of core (BM) At the stage of winding Loss of prestress in longitudinal wire at winding 1411.84 x5x5x 1OOO= 4411985Nm = Total losses x 0.9 =212.63 x 0.9= 191.37 N/mm2 8 Stress in longitudinal wire at winding (l,iW) = 1286.25 – 191.37~,lW 1094.88 N/mm2 = BM Stredue to self weight of core =~=iO.5949 N/rnni2 2 14
  17. 17. IS 784:2001D-3.8 Stress Due to Transport and Handling D-3.9 Summary of Stresses in Longitudinal Direc- tion Bending moment = 8.44 x 107 (see Note 3 under 7.4.1) Stresses due to Compressive Tensile Modulus of circular section of pipe (Zl) N/mm2 N/mm2 Maximum local longitudinal — –3.026 7 3.1416 6144-5004 tensile stress due to ben- =12 731 728mm3 ding during winding 32 x 614 Beam action + 1.3769 –1.376 9 Self weight of core + 0.5949 -0.5949 Stress due to transport and handling = Transport and unloading + 6.6291 -6.6291 Initial precompression + 4.3975 — Bending Moment = 8.44 x 107 = + b 629 ~N, -2 Precompression at winding +3.743 2 — z, 12731728 – “ Final precompression + 3.6705 —D-3.1O Load Combination of Longitudinal StressesUnder Different Condition (see 7.4.1)Actual against Permissible .Loading Longitudinal Stresses, Nlmm2Combination Tensile Compressive / — - / — - Actual Permissible Actual Permissiblea) Longitudinal Minimum residual prestress in barrel — — compressive stress (after losses) +3.6705 +2.5b) Longitudinal - (3.026 7 + 0.5949) 0.56x (@05 0.56x (0.5949+ 3.7432) 0.5 x (2)0”5 25 x prestress during + 3.7432 = +0.121 6 (25)05= –2.800 O = + 4.3381 = 12.5000 winding +0.121 6 c -2.8000 +4.338 1 c 12.5000c) Longitudinal (-1.376 9 + 3.670 5) 0.34X )05 0.34x (1.3769+ 3.6705) 0.5x (f)05X40 prestress after = +2.293 6 (40)05 = -2.1503 =+5.0474 = 20.0 losses plus beam +2.293 6-2.1503 +5.047 420.0 actiond) Handling before (-0.594 9 + 3.743 2) -0.67 (0.594 9 + 3.743 2) 0.5 x ~p,)o”sx 15 winding = +3.148 3 = + 4.3381 = 7.5 +3.148 3 c – 0.67 + 4.3381 c 7.5e) Transport and -6.6291 + 3.6705 = 0.56 x )05 0.56 x +6.629 1 + 3.6705 0.5 x )0”5 x 40 unloading -2.9586 (40)’J”5= -3.5417 = +10.299 6 =20 -2.9586 c – 3.5417 +10.299 620.0 15
  18. 18. IS 784:2001 ANNEX E (Clause 7.4.3) THRUST AND MOMENT COEFFICIENTSE-1 The coefficients at control sections for bedding angles from 30° to 180° developed by use of Olander’sEquations are as given below: / /q-- , OEDlp f / // - .- Bedding Location of Thrust Coefficients, Ct Moment Coeflcient, Cm Angle Control . Section, 0 Pipe Water Earth Pipe Water Earth Ctp Ctw C,e C,p C*W c,, 0° -0.078 -0.237 +0.487 +0.079 +0.079 +0.062 30° 104° +0.302 4.058 +0.633 +0.100 +0.100 +0.085 180° +0.125 -0.352 +0.376 +0.194 +0.194 +0.173 0° –0.071 -0.230 +0.425 +0.076 +0.076 +0.065 60° 104° +0.302 -0.059 +0.576 +0.096 +0.096 +0.086 180° +0.168 -0.310 +0.345 +0.155 +0.155 +0.145 0° –0.061 -0.220 +().382 +0.070 +0.070 +0.069 90° 104° +0.295 –0.062 +0.539 +0.088 +0.088 +0.089 180° +0.207 -0.270 +0.326 +0.121 +0.121 +0.125 0° -0.046 -0.205 +0.35 1 +0.063 +0.063 +0.073 120° 100° +0.282 –0.065 +0.516 +0.077 +0.077 +0.09 1 180° +0.245 –0.233 +0.316 +0.091 +0.091 +0.109 0° –0.026 –0.185 +0.331 +0.054 +0.054 +0.079 150° 96° +0.267 -0.067 +0.504 +0.063 +0.063 +0.094 180° +0.282 –0.196 +0.313 +0.065 +0.065 +0.097 0° –0.000 -0.159 +0.318 +0.044 +0.044 +0.087 180° 90° +0.250 -0.068 +0.500 +0.047 +0.047 +0.095 180° +0.318 –0.159 +0.318 +0.044 +0.044 +0.087 16
  19. 19. IS 784:2001 ANNEX F (Clauses 7.5, G-3 and J-4.2.2. 1) LOSS OF PRESTRESSF-1 Explanation of various symbols used in subse- wherequent clause is given in Annex K. ~,,”n~ = Initial stress in core in longitudinalF-2 CALCULATION FOR LOSS OF PRESTRESS direction in N/mm2. Longitudinal Circum- ~, = Initial stress in core in circumferentialsl direction in N/mm*.No. (Pre Tensioning) ferential (Post Lih3ng = Initial stress in core in circumferential Tensioning) wire in N/mm*.1. Elastic deformation — 3.2i E, = Modulus of elasticity of high tensile2. Relaxation of wire 0.16 i10.~ 0.16Ji wire.3. Deformation due to 2“5fsi long 2.5~i . 2.00 x 105N/mm2 (for stress relieved), creep and4. Deformation due to 0.0001 E, 0.0001 E, = 1.93 x 10s N/mm2 (for as drawn). shrinkage L= Effective length of pipe in mm5. Yield due to mould + 80 mm. shortening (wire stretch 2 E, due to filling vibrations L+80 NOTE— Lossof stress in high tensile wire at factory test pressure will be 90 pereent of the total losses. during spinning, etc, slippage = 2 mm) ANNEX G (Clauses 7.6, H-3.3 and J-5) TYPICAL DESIGN OF PRESTRESSED CONCRETE PIPE OF DIA 1200 mm — WINDING BY PROCESS OF COUNTER WEIGHT/BREAKG-1 Explanation of various symbols used in subse- Process for winding Counter Weight/quent clauses is given in Annex K. Break Core thickness, T, = 70 mmG-2 DATA Coat thickness, Th = 22 mm Diameter of pipe, D = 1200 mm Width of trench - = 1.984 m Effective length of pipe, L = 5.0 m (D+ 2TC+ 2T~+ 600), B, Working pressure, PW(see 3.4) = 0.700 N/mm* Diameter of circumferential =4mm Site test pressure, P, = 1.050 N/mm2 wire, d~ Factory test pressure, P~ = 1.150 Nhnrn2 Diameter of longitudinal = 4mm Height of fill, H = 1.00m wire, dC Density of fill material, K, = 19700 N/m3 Number of longitudinal, N = 28 Live load Class AA (IRC) Ultimate tensile strength of = 1 715 N/mm2 circumferential wire (see 4.5.1)G-3 ASSUMPTIONS = 1 715 N/mm2 Ultimate tensile strength of Density of core concrete, KC = 24000 N/m3 longitudinal wire (see 4.5.1) Density of coating, Kb = 21600 N/m3 Area of circumferential wire, A, = 0.623mm2/mm Density of water, KW = 10000 N/m3 Modulus of elasticity of steel, E, = 20x104 N/mm* 17

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