1、BSI Standards Publication PD CEN/TR 1295-4:2015 Structural design of buried pipelines under various conditions of loading Part 4: Parameters for reliability of the designPD CEN/TR 1295-4:2015 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation of CEN/TR 1295-4:2015.
2、 The UK participation in its preparation was entrusted to Technical Committee B/505, Wastewater engineering. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Use
3、rs are responsible for its correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 89114 4 ICS 23.040.01 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the autho
4、rity of the Standards Policy and Strategy Committee on 30 September 2015. Amendments issued since publication Date 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
5、 under various conditions 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 versch
6、iedenen Belastungsbedingungen - 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,
7、Czech Republic, Denmark, 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
8、. EUROPEAN COMMITTEE FOR 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
9、:2015 EPD CEN/TR 1295-4:2015 CEN/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
10、 data and characteristics . 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 Param
11、eters for limit states analysis 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 1295-4:2015 CEN/TR 1295-4:2015 (E) 3 European for
12、eword This document (CEN/TR 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 sha
13、ll not be held responsible 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 desi
14、gn (CEN/TR); Part 3: Common method (CEN/TR); Part 4: Parameters for reliability of the design (CEN/TR). PD CEN/TR 1295-4:2015 CEN/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 ext
15、ensive study and research, in 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
16、variations, as well as different 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
17、the development of a European 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,
18、 whilst working towards a common 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 pipeli
19、nes under various conditions 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 publis
20、hed as CEN/TR 1295-3 “Structural 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.
21、 In 2011, CEN/TC 165 has decided 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 1295-4:2015 CEN/TR 1295-4:2015 (E) 5 1 Scope Thi
22、s Technical Report lists the 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 doc
23、ument identifies the parameters 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 12
24、95-1. This Technical Report does 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 o
25、f this document. Design parameters 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 direct
26、ion or cross-section) are not 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
27、 edition of the referenced document (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 Instal
28、lation terms Installation terms are given in Figure 1. The same terms apply for embankment installations and for trenches with sloping sides. PD CEN/TR 1295-4:2015 CEN/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
29、 11 depth of bedding 4 main backfill 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 in
30、stallation 3.1.1 compaction deliberate 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 arr
31、angement and type(s) of material(s) around a buried pipeline which contribute to its structural performance SOURCE: EN 1295-1:1997, 3.1.3 PD CEN/TR 1295-4:2015 CEN/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, inc
32、luding surge, that a component 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
33、) maximum hydrostatic pressure 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 wit
34、h a particular embedment, to the 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 SOURC
35、E: EN 805:2000, 3.1.4 3.2.6 limit 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 SO
36、URCE: EN 1295-1:1997, 3.2.3 PD CEN/TR 1295-4:2015 CEN/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
37、 is a fixed allowance for surge; 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 1990:200
38、2, 1.5.2.14 3.2.10 silo effect effect 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 ens
39、ure its integrity and tightness 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 c
40、onstruction and operation, without 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 desi
41、gner shall state the chosen method 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 calcu
42、lation. Methods of design, when 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, th
43、e designer shall use the whole method 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 1295-4:2015 CEN/TR 1295-4:2015 (E) 9 Probable consequences of pipeline failure
44、 shall be identified prior to the 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
45、factors of safety, shall be in accordance 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. T
46、he designer needs to clearly state 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 co
47、nstruction loads parameters, iii) 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 a
48、nd experimental studies of pipelines 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 s
49、upervision, control measurement and 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 1295-4:2015 CEN/TR 1295-4:2015 (E) 10 1) The design procedure shall aim to predict the mean values of loads, and shall compare these
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