1、 Reference number ISO 10803:2011(E) ISO 2011INTERNATIONAL STANDARD ISO 10803 Second edition 2011-12-01 Design method for ductile iron pipes Mthode de calcul des tuyaux en fonte ductile ISO 10803:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of
2、 this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH
3、-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedISO 10803:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv 1 Scope 1 2 Normative references 1 3 Terms and definitions . 1 4 De
4、sign procedure 2 5 Design for internal pressure 3 6 Design for external loads 3 Annex A (informative) Dimensions of preferred and other class pipes 9 Annex B (informative) Allowable depths of cover for pipes conforming to ISO 2531 . 12 Annex C (informative) Allowable depths of cover for pipes confor
5、ming to ISO 7186 . 54 Annex D (informative) Trench types . 58 Annex E (informative) Soil classification 59 Bibliography 60 ISO 10803:2011(E) iv ISO 2011 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO me
6、mber bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governme
7、ntal and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Dire
8、ctives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bod
9、ies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 10803 was prepared by Technical Committee ISO/TC 5, Ferrous metal pipes and m
10、etallic fittings, Subcommittee SC 2, Cast iron pipes, fittings and their joints. This second edition cancels and replaces the first edition (ISO 10803:1999), which has been technically revised. INTERNATIONAL STANDARD ISO 10803:2011(E) ISO 2011 All rights reserved 1Design method for ductile iron pipe
11、s 1 Scope This International Standard specifies the design of ductile iron pipes used for conveying water, sewerage and other fluids with or without internal pressure, and with or without earth and traffic loading. 2 Normative references The following referenced documents are indispensable for the a
12、pplication of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2531, Ductile iron pipes, fittings, accessories and their joints for water applications ISO 7186, Ductile i
13、ron products for sewerage applications ISO 7268, Pipe components Definition of nominal pressure ISO 10802, Ductile iron pipelines Hydrostatic testing after installation 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 7268 and the following apply. 3.1
14、 allowable operating pressure PFA maximum internal pressure, excluding surge, which a component can safely withstand in permanent service 3.2 allowable maximum operating pressure PMA maximum internal pressure, including surge, which a component can safely withstand in service 3.3 allowable site test
15、 pressure PEA maximum hydrostatic pressure that a newly installed component can withstand for a relatively short duration, when either fixed above ground level or laid and backfilled underground, in order to ensure the integrity and leaktightness of the pipeline NOTE This test pressure is different
16、from the system test pressure, which is related to the design pressure of the pipeline. ISO 10803:2011(E) 2 ISO 2011 All rights reserved3.4 embedment arrangement and type(s) of material around a buried pipeline, which contribute to its structural performance See Figure D.1. 3.5 bedding lower part of
17、 the embedment, composed of the lower bedding (if necessary) and the upper bedding See Figure D.1. 3.6 bedding reaction angle conventional angle used in the calculation model to account for the actual soil pressure distribution at pipe invert 3.7 compaction deliberate densification of soil during th
18、e installation process 3.8 standard Proctor density degree of soil compaction, as defined in AASHTO T99 using a 2,5 kg rammer and a 305 mm drop 4 Design procedure 4.1 The pipe wall thickness shall provide adequate strength against the internal pressure of the fluid and against the effects of externa
19、l loads due to backfill and surcharge, i.e. traffic loadings. Ductile iron pipes in compliance with ISO 2531 are classified according to their allowable operating pressure for use in water applications. Ductile iron pipes in compliance with ISO 7186 are for sewerage applications either under pressur
20、e or under gravity. Using the equations given in Clauses 5 and 6, the design of buried pipes is performed by determining a) the minimum pipe wall thickness for the allowable operating pressure (PFA), and b) the depths of cover as given in Annexes B and C. 4.2 The design procedure for the pipes is th
21、e following: a) from the allowable operating pressure of the pipeline, select the class of pipe as appropriate from ISO 2531 or ISO 7186 the minimum pipe wall thickness of these pipes has been calculated from Equation (1); b) calculate the allowable depth of cover in accordance with Clause 6; c) if
22、the allowable depth of cover is not adequate, select higher a pressure class of pipe and repeat steps 4.2 a) and b) until the allowable depth of cover is acceptable. NOTE 1 In practice, in most cases, the pressure class and the allowable depth of cover for the pipes can be selected from the appropri
23、ate tables in Annexes B or C without carrying out the detailed calculations as explained above. NOTE 2 When installed and operated under the conditions for which they are designed, ductile iron pipes, fittings, accessories and their joints maintain all their functional characteristics over their ope
24、rating life, due to constant material properties, to the stability of their cross-section and to their design with high safety factors. NOTE 3 In certain countries, national standards or regulations can specify other design procedures. ISO 10803:2011(E) ISO 2011 All rights reserved 35 Design for int
25、ernal pressure 5.1 Design equation for wall thickness The minimum wall thickness of pipes, e min , shall be not less than 3 mm (as specified in ISO 2531) or 2,4 mm (ISO 7186) and shall be determined using Equation (1): min m PFA SF DE 20 (PFA SF) e R (1) where e minis the minimum pipe wall thickness
26、 to resist hoop stress due to internal pressure, in millimetres; PFAis the allowable operating pressure, in bar 1)(see 5.2); SF is the design safety factor (see 5.2); DE is the nominal pipe external diameter, in millimetres (see Annex A); R mis the minimum ultimate tensile strength of the ductile ir
27、on, in megapascals (R m 420 MPa in ISO 2531 and ISO 7186). Nominal wall thickness, e nom , of the pipe is calculated as given by Equation (2): nom min1,3 0,001DN ee (2) where DN is the nominal diameter of pipe as defined in ISO 2531 and ISO 7186, in millimetres. Nominal pipe wall thicknesses for var
28、ious classes in accordance with ISO 2531 are given in Table A.1 and nominal pipe wall thicknesses for pressure and gravity pipe classes in accordance with ISO 7186 are given in Table A.2. 5.2 Design safety factors The minimum pipe wall thickness, e min , shall be calculated with a design safety fact
29、or of 2,5 for the maximum allowable operating pressure (i.e. PMA as indicated in ISO 2531 and ISO 7186) and a design safety factor of 3 for the allowable operating pressure (i.e. PFA as indicated in ISO 2531 and ISO 7186). NOTE This allows field testing of installed ductile iron pipelines in complia
30、nce with ISO 10802 by application of test pressures up to the allowable test pressures given in ISO 2531 and ISO 7186. 6 Design for external loads 6.1 Design equation x 100 80 , 0 6 1 Kq SE (3) or 1) 100 kPa = 1 bar = 0,1 MPa; 1 MPa = 1 N/mm 2 . ISO 10803:2011(E) 4 ISO 2011 All rights reserved x8 0,
31、061100 SE q K (3) where is the pipe diametral deflection, in percent of external diameter, D; K xis the deflection coefficient depending on bedding reaction angle; q is the vertical pressure at pipe crown due to all external loads, in megapascals; S is the pipe diametral stiffness, in megapascals, 3
32、 () EI S D where E is the modulus of elasticity of the pipe wall material, in megapascals (170 000 MPa for ductile iron); I 3 stiff 12 e is the second moment of area of the pipe wall per unit length, in millimetres to the third power; D is the mean diameter of pipe in millimetres; stiff DE , e DE is
33、 the nominal pipe external diameter as specified in ISO 2531 and ISO 7186, in millimetres; e stiffis the average of the minimum pipe wall thickness of the pipe and nominal wall thickness of pipe, in millimetres; E is the modulus of soil reaction, in megapascals. Pipe material stiffness values, S, ma
34、y be taken from the relevant annexes of ISO 2531 and ISO 7186. The values of E and K xare given in Table 1 for each trench type and soil group. NOTE The design equation is based on the Spangler model (see Figure 1), where the vertical pressure, q, is acting downward and: is uniformly distributed at
35、the pipe crown over a diameter; is in equilibrium with a pressure, acting upward at the pipe invert, uniformly distributed over the bedding reaction angle 2 ; causes a pipe deflection, which gives rise to a horizontal reaction pressure at pipe sides, parabolically distributed over an angle of 100. I
36、SO 10803:2011(E) ISO 2011 All rights reserved 5Key 1 vertical pressure, q 2 lateral reaction pressure = 0,01 E 3 vertical reaction pressure = q/sin Figure 1 Spangler model 6.2 Loads applied to the pipe and calculation for the allowable depth of cover 6.2.1 General The total vertical pressure, q, act
37、ing at pipe crown is the sum of the following components: 12qqq (4) where q 1is the pressure from earth loads; q 2is the pressure from traffic loads; NOTE The pressure from traffic loads, q 2 , is greater than that from normal static loads applied to the ground surface; however, any abnormal surface
38、 loading can require special consideration. The value of q obtained from Equation (4) is basically a function of H (allowable depth of cover), i.e. () qfH (5) Equating this to Equation (3) (see 6.1): x (8 0, 061 ) () () ( 1 0 0 ) SE fH K (6) The value of allowable depth of cover, H, may be determine
39、d after calculating the value of q as given in 6.2.2 and 6.2.3 and other parameters as defined. ISO 10803:2011(E) 6 ISO 2011 All rights reserved6.2.2 Pressure from earth loads Equation (7) shall be used to calculate q 1from the weight of the earth prism immediately above the pipe: 1 0,001 qH (7) whe
40、re q 1is the pressure at pipe crown, in megapascals; is the unit weight of the backfill, in kilonewtons per cubic metre; H is the height of cover (distance from pipe crown to ground surface), in metres. In the absence of other data, the unit weight of the soil is taken as being equal to 20 kN/m 3in
41、order to cover the vast majority of cases. If a preliminary geotechnical survey determines that the actual unit weight of the backfill is less than 20 kN/m 3 , the actual value may be used for determining q 1 . If, however, it appears that the actual value is more than 20 kN/m 3 , the actual value s
42、hould be used. 6.2.3 Pressure from traffic loads The value of q 2shall be calculated using Equation (8), based on wheel load taken from national and/or local applicable standards and regulations. 4 2 0,04 (1 2 10 DN) q H (8) where q 2is the pressure at pipe crown, in megapascals; is a traffic load f
43、actor; the following are the given values: 1,5: this is the general case, except access roads; 0,75: roads where truck traffic is prohibited; 0,50: all other cases; H is the height of cover, in metres; DN is the nominal size. NOTE 1 Equation (8) is not applicable when H 0,3 m. In the case where a na
44、tional standard exists for the traffic loadings, the value of may be given as follows: 100 P (9) where P is the wheel load, in kilonewtons, for a particular type of road according to the respective national standard. All pipelines shall be designed for at least 0,5 and pipelines laid adjacent to roa
45、ds shall be designed to withstand the full road loading. ISO 10803:2011(E) ISO 2011 All rights reserved 7NOTE 2 For pipelines under railroads or airports or subjected to heavy construction traffic, special requirements can apply according to the respective national standard and regulations. 6.3 Soil
46、 and pipe interaction The bedding reaction angle depends on the installation conditions (bedding, sidefill compaction) and on the pipe diametral deflection (especially for large sizes). The modulus of soil reaction, E , of the sidefills depends on the type of soil used for the embedment and upon the
47、 trench type (see Annex D). In the absence of applicable standards or other data, the values of E indicated in Table 1 may be used at the design stage for five typical trench types and for six soil groups (see Annex E for the classification of soils). These data are valid for pipes laid under embank
48、ments as well as in trenches. A preliminary geotechnical survey should be carried out to facilitate identification of the soil and proper selection of E values. E values given in Table 1 apply when trench shoring is left in place or removed in such a way as to allow compaction of sidefill against th
49、e native trench wall; otherwise, reduced E values should be applied. In very poor ground conditions, it may be necessary to use soil stabilization matting to prevent migration of embedment with resultant loss of soil reaction modulus, E . Table 1 Modulus of soil reaction, E Trench type 1 2 3 4 5 Placement of embedment Dumped Very light compaction Light compaction Medium compaction High compactio
