1、BSI Standards PublicationPD CEN/TR 1295-4:2015Structural design of buriedpipelines under variousconditions of loadingPart 4: Parameters for reliability of thedesignPD CEN/TR 1295-4:2015 PUBLISHED DOCUMENTNational forewordThis Published Document is the UK implementation of CEN/TR1295-4:2015.The UK pa
2、rticipation in its preparation was entrusted to TechnicalCommittee B/505, Wastewater engineering.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsi
3、ble for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 89114 4ICS 23.040.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This Published Document was published under the authority of theStandards P
4、olicy and Strategy Committee on 30 September 2015.Amendments issued since publicationDate Text affectedPD CEN/TR 1295-4:2015TECHNICAL REPORT RAPPORT TECHNIQUE TECHNISCHER BERICHT CEN/TR 1295-4 September 2015 ICS 23.040.01 English Version Structural design of buried pipelines under various conditions
5、 of loading - Part 4: Parameters for reliability of the design Calcul de rsistance mcanique des canalisations enterres sous diverses conditions de charge - Partie 4 : Paramtres pour la fiabilit de la conception Statische Berechnung von erdverlegten Rohrleitungen unter verschiedenen Belastungsbedingu
6、ngen - Teil 4: Parameter fr die Zuverlssigkeit der Auslegung This Technical Report was approved by CEN on 13 April 2015. It has been drawn up by the Technical Committee CEN/TC 165. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark,
7、Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR
8、STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TR 1295-4:2015 EPD CEN/TR 1295-4:2
9、015CEN/TR 1295-4:2015 (E) 2 Contents Page European foreword . 3 Introduction 4 1 Scope 5 2 Normative references 5 3 Terms and definitions . 5 3.1 Installation terms 5 3.2 Design terms . 7 4 General requirements . 8 5 Declaration of the parameters . 9 5.1 General 9 5.2 Input data and characteristics
10、. 10 5.2.1 Pipe parameters . 10 5.2.2 External loads parameters . 11 5.2.3 Internal pressure parameters . 14 5.2.4 Pipe own weight parameters . 15 5.2.5 Weight of fluid . 15 5.2.6 Subsidence (differential settlement) parameters 15 5.2.7 Temperature parameters . 16 5.3 Parameters for limit states ana
11、lysis 16 5.4 Safety parameters 19 Annex A (informative) Checklist for parameters for reliability of the structural design of buried water and waste water pressure pipelines, drains and sewers . 20 Bibliography . 23 PD CEN/TR 1295-4:2015CEN/TR 1295-4:2015 (E) 3 European foreword This document (CEN/TR
12、 1295-4:2015) has been prepared by Technical Committee CEN/TC 165 “Wastewater engineering”, the secretariat of which is held by DIN. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible
13、for identifying any or all such patent rights. This document, EN 1295: “Structural design of buried pipelines under various conditions of loading”, consists of the following parts: Part 1: General requirements (EN); Part 2: Summary of nationally established methods of design (CEN/TR); Part 3: Common
14、 method (CEN/TR); Part 4: Parameters for reliability of the design (CEN/TR). PD CEN/TR 1295-4:2015CEN/TR 1295-4:2015 (E) 4 Introduction The structural design of buried pipelines constitutes a wide ranging and complex field of engineering, which has been the subject of extensive study and research, i
15、n many countries over a period of very many years. While many common features exist between the design methods, which have been developed and established in the various member countries of CEN, there are also differences reflecting such matters as geological and climatic variations, as well as diffe
16、rent installation and working practices. In view of these differences, and of the time required to develop a common design method that would fully reflect the various considerations identified in particular national methods, a multiple stage approach has been adopted for the development of a Europea
17、n Standard. In accordance with this approach, a Joint Working Group, at its initial meeting, resolved “first to produce an EN giving guidance on the application of nationally established methods of structural design of buried pipelines under various conditions of loading, whilst working towards a co
18、mmon method of structural design”. EN 1295-1, “Structural design of buried pipelines under various conditions of loading Part 1: General requirements” represents the implementation of the first part of that resolution, and CEN/TR 1295-2 “Structural design of buried pipelines under various conditions
19、 of loading Part 2: Summary of nationally established methods of design” represents the full implementation of the first part of that resolution. In 2003, CEN/TC 164 and CEN/TC 165 accepted a recommendation from JWG1 that the two structural design options should be published as CEN/TR 1295-3 “Struct
20、ural design of buried pipelines under various conditions of loading Part 3: Common method”, because there was no prospect of the group reaching agreement on a “Common Method”, and the human and financial resources needed to continue were, in any case, no longer available. In 2011, CEN/TC 165 has dec
21、ided to complete this approach to list the parameters for the reliability of the structural design of buried water and wastewater pressure pipelines, drains and sewers in relation with the installation conditions. PD CEN/TR 1295-4:2015CEN/TR 1295-4:2015 (E) 5 1 Scope This Technical Report lists the
22、parameters for the reliability of the structural design of buried water and wastewater pressure pipelines, drains and sewers. The reliability of the design of buried pipelines is based on the selection of appropriate design parameters for a chosen design method. This document identifies the paramete
23、rs appropriate to the chosen design method, which should all be clearly stated. This Technical Report does not aim to specify the requirements for the structural design of water and wastewater pressure pipelines, drains and sewers. These requirements are defined in EN 1295-1. This Technical Report d
24、oes not apply for offshore laying, pipes supported on piles, no dig pipelines, or laid above ground. Supplementary considerations need to be taken into account for these specific installations. Special situations (e.g. landslide, earthquake, fire) are outside the scope of this document. Design param
25、eters for calculation of longitudinal effects (including bending moments, shear forces and tensile forces resulting for example from non-uniform bedding and thermal movements and, in the case of pressure pipelines, from Poissons contraction and thrust at change of direction or cross-section) are not
26、 covered in this document. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced do
27、cument (including any amendments) applies. EN 1295-1, Structural design of buried pipelines under various conditions of loading - Part 1: General requirements 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 Installation terms Installation ter
28、ms are given in Figure 1. The same terms apply for embankment installations and for trenches with sloping sides. PD CEN/TR 1295-4:2015CEN/TR 1295-4:2015 (E) 6 Key 1 surface 9 trench bottom 2 bottom of road or railway construction, if any 10 depth of cover 3 trench walls 11 depth of bedding 4 main ba
29、ckfill 12 depth of embedment 5 initial backfill 13 trench depth 6 sidefill a thickness of lower bedding 7 upper bedding b thickness of upper bedding 8 lower bedding c thickness of initial backfill NOTE The terms in Figure 1 are the same as in EN 1610. Figure 1 Trench installation 3.1.1 compaction de
30、liberate densification of soil during the construction process SOURCE: EN 1295-1:1997, 3.1.1 3.1.2 consolidation time-dependent densification of soil by processes other than those deliberately applied during construction SOURCE: EN 1295-1:1997, 3.1.2 3.1.3 embedment arrangement and type(s) of materi
31、al(s) around a buried pipeline which contribute to its structural performance SOURCE: EN 1295-1:1997, 3.1.3 PD CEN/TR 1295-4:2015CEN/TR 1295-4:2015 (E) 7 3.2 Design terms 3.2.1 allowable maximum operating pressure (PMA) maximum pressure occurring from time to time, including surge, that a component
32、is capable of withstanding in service SOURCE: EN 805:2000, 3.1.1 3.2.2 allowable operating pressure (PFA) maximum hydrostatic pressure that a component is capable of withstanding continuously in service SOURCE: EN 805:2000, 3.1.2 3.2.3 allowable site test pressure (PEA) maximum hydrostatic pressure
33、that a newly installed component is capable of withstanding for a relatively short duration, in order to ensure the integrity and tightness of the pipeline SOURCE: EN 805:2000, 3.1.3 3.2.4 bedding factor ratio of the maximum design load for the pipe, when installed with a particular embedment, to th
34、e test load which produces the same maximum bending moment SOURCE: EN 1295-1:1997, 3.2.1 3.2.5 design pressure (DP) maximum operating internal pressure of the system or of the pressure zone fixed by the designer considering future developments but excluding surge SOURCE: EN 805:2000, 3.1.4 3.2.6 lim
35、it states states beyond which the structure no longer fulfils the relevant design criteria SOURCE: EN 1990:2002, 1.5.2.12 3.2.7 load bearing capacity load per unit length that a particular combination of pipe and embedment can sustain without exceeding a limit state SOURCE: EN 1295-1:1997, 3.2.3 PD
36、CEN/TR 1295-4:2015CEN/TR 1295-4:2015 (E) 8 3.2.8 maximum design pressure (MDP) maximum operating internal pressure of the system or of the pressure zone fixed by the designer considering future developments and including surge, where: MDP is designated MDPa when there is a fixed allowance for surge;
37、 MDP is designated MDPc when the surge is calculated SOURCE: EN 805:2000, 3.1.5 3.2.9 serviceabilty limit states states that correspond to conditions beyond which specified service requirements for a structure or structural member are no longer met SOURCE: EN 1990:2002, 1.5.2.14 3.2.10 silo effect e
38、ffect whereby lateral earth pressure in trench backfill causes friction at the trench wall to carry part of the weight of the backfill SOURCE: EN 1295-1:1997, 3.2.5 3.2.11 system test pressure (STP) hydrostatic pressure applied to a newly laid pipeline in order to ensure its integrity and tightness
39、3.2.12 ultimate limit states states associated with collapse or with other similar forms of structural failure SOURCE: EN 1990:2002, 1.5.2.13 4 General requirements All pipelines shall withstand the various loadings to which they are expected to be subjected, during construction and operation, witho
40、ut detriment to their function and to the environment. The designer of the pipeline shall therefore specify the parameters for the structural design. These parameters shall be consistent with the requirements of the installation and the earthworks. The structural designer shall state the chosen meth
41、od for the design. The structural designer shall determine whether or not the pipeline comes within the scope of the chosen method of design including level of safety. The structural designer shall declare the selected parameters to ensure the reliability of the calculation. Methods of design, when
42、presented in the form of tables, charts or computer programmes, shall be deemed equivalent to a full calculation, provided that any simplification does not reduce the level of safety below that which would be obtained by a full design. For the chosen design method, the designer shall use the whole m
43、ethod including the associated allowable limits on the results and shall assess that the chosen method is applicable for the project and shall express the resulting design safety. PD CEN/TR 1295-4:2015CEN/TR 1295-4:2015 (E) 9 Probable consequences of pipeline failure shall be identified prior to the
44、 structural design. The structural designer shall consider probable consequences of pipeline failure by establishing an acceptable level of safety consistent with the chosen design method. At each stage of the design, the values of the selected parameters, including factors of safety, shall be in ac
45、cordance with the chosen method and with site conditions, and shall be stated by the structural designer. 5 Declaration of the parameters 5.1 General The designer shall state the chosen method by referring to a published document or by a detailed description of it. The designer needs to clearly stat
46、e the input data used and the analyses done. The designer shall state the selected parameters, and at least refer to the following: a) input data and characteristics: 1) pipe parameters; 2) external loads parameters: i) soil loads parameters, ii) traffic loads and construction loads parameters, iii)
47、 groundwater parameters; 3) internal pressure parameters; 4) pipes own weight parameters; 5) weight of fluid parameters; 6) subsidence parameters; 7) temperature parameters; b) parameters for limit state analysis; c) safety parameters. As stated in EN 1295-1: Field and experimental studies of pipeli
48、nes show variations in observed earth pressures and pipe deformations, stresses and strains. The main cause of these variations is the inevitable inconsistency of soil characteristics and construction practices. The magnitude of the variation can be reduced by good supervision, control measurement a
49、nd by the use of fill materials, which are easily placed and treated, but some degree of variation is inevitable. Variations in pipe characteristics, such as strength or elasticity, also occur in practice. Appropriate allowance for these variations should be made at the design stage and be in accordance with one of the following design philosophies: PD CEN/TR 1295-4:2015CEN/TR 1295-4:2015 (E) 10 1) The design procedure shall aim to predict the mean values of loads, and shall compare these with the load bearing capacity of t
