BS ISO 21052:2021:2022 Edition
$167.15
Restrained joint systems for ductile iron pipelines. Calculation rules for lengths to be restrained
Published By | Publication Date | Number of Pages |
BSI | 2022 | 34 |
This document specifies a computation method used to determine the length of the ductile iron pipes to be restrained, when used for conveying raw water, drinking water, sewerage under pressure.
This computation method takes into account all common pipeline route changes, including changes in the diameter of the pipeline itself and dead ends at the extremity of the pipeline, the outside diameter of the pipe, the system test pressure (to estimate the thrust), depth of cover, the characteristics of the soil surrounding the pipe and trench backfilling methods for a worldwide usage. The characteristics of the restrained joint are not covered by this document but can also be considered to determine the restraining length using any appropriate method.
The computation method defined in this document is applicable to all types of restrained joint systems, with their operating pressure ratings of ductile iron pipelines complying with ISO 2531 , ISO 7186 and ISO 16631 .
ISO 10804 deals with actual design of the joint for various operating pressures of the pipeline.
National standards or established calculation methods can be used instead of this ISO standard.
PDF Catalog
PDF Pages | PDF Title |
---|---|
2 | National foreword |
7 | Foreword |
9 | 1 Scope 2 Normative references 3 Terms, definitions and symbols 3.1 Terms and definitions |
11 | 3.2 Symbols |
12 | 4 Thrust restraint principles, calculation rules and general specification 4.1 Thrust forces 4.2 Calculation rules and general specification |
13 | 4.3 Standard jointing systems offer no longitudinal restraint 4.4 Restrained joint systems 4.5 Length to be restrained 4.6 Restrained design method 4.7 Gravity thrust blocks |
14 | 5 Thrust force 5.1 Internal hydrostatic pressure in straight pipes 5.2 Internal hydrostatic pressure in bends |
15 | 5.3 Internal hydrostatic pressure in other configurations 6 Restrained joints 6.1 Principle |
16 | 6.2 Conservative design 6.3 Required prevailing site conditions 7 Unit frictional force, F s 7.1 Static frictional force 7.2 Values of soil cohesion |
17 | 8 Polyethylene encasement and PU coating and other extruded organic coatings 9 Unit bearing resistances, R s 9.1 Lateral resistance, passive soil pressure |
18 | 9.2 Design value of passive soil pressure 9.3 Empirical values of passive soil pressure |
21 | 10 Application to common situations 10.1 Horizontal bends |
22 | 10.2 Vertical down bends |
23 | 10.3 Vertical up bends 10.4 Tees |
24 | 10.5 Reducers |
25 | 10.6 Dead ends 10.7 Encroaching restrained lengths 10.8 Equal angle vertical offset (θ) |
26 | 10.9 Combined horizontal equal angle bends (θ) |
27 | 10.10 Combined horizontal unequal angle bends |
28 | 10.11 Combined vertical equal angle offsets (θ) 10.11.1 Pipeline under obstruction |
29 | 10.11.2 Pipeline over obstruction 11 Restrained lengths 12 Installation and laying instruction 12.1 Select backfill considerations 12.1.1 Backfill material versus native soil support characteristics 12.1.2 Swamps or marshes 12.2 Combining thrust blocks/anchor blocks and restrained joints |
30 | 12.3 Pipe in a casing 12.3.1 Restrained lengths inside casing 12.3.2 Balancing the thrust force with restraining lengths outside the casing 12.4 Future excavations |
31 | Annex A (informative) Dimensions and unit weights of pipes filled with water for preferred class |
32 | Annex B (informative) Soil classification chart |
33 | Bibliography |