Our site uses cookies necessary for its proper functioning. To improve your experience, other cookies may be used: you can choose to disable them. This can be changed at any time via the Cookies link at the bottom of the page.


Taking the stress and strain of buried thermoplastic pipe design

 

Applications & Jointing # 1995 Edinburgh

This paper summarises current design practices for buried thermoplastic pipelines subjected to combined gravity and internal pressure loadings. It suggests that accurate predictions of stabilised deformations are neither possible nor necessary, but that appropriate structural design methodologies should instead be limit slate based. The latter concept is first considered with reference lo observed behaviour under gravity loads only, and then the likely effect of internal pressurisation is addressed. Existing reservations about current European design approaches are reinforced, in particular with respect to stress and strain value derivations - moreover in the case of thermoplastic pressure pipes it is noted that the beneficial effects of stress redistribution and creep relaxation are generally not taken into consideration. It is concluded that now is an ideal time to review the weaknesses and conservatisms in current design practices and then to develop user friendly analytical techniques that are more appropriate to modem thermoplastic pipe materials.

Please note that the whole article content is available on PPCA website only


Related papers

2006 Washington DC : Development of a Whole Life Costing Model for Large Diameter Water Mains

Author(s) : Shepherd, Headford, Jordan, Reeves, Walton

In Europe polyethylene (PE) has been chosen almost exclusively for gas mains for many years because of economic, technical and safety reasons but in the water industry a number of different materials are still used for pressure water mains. Indeed at sizes above 355mm (14 inch) most new large diameter water mains are...

2004 Milan : 20+ Years Experience with PE Pipe for Water in the UK

Author(s) : Headford, Hill, Wilson

The United Kingdom is the most highly developed PE pressure pipe market in the world. Following pioneering work done in the USA and Germany, it was the UK that was first to adopt PE on a large scale for gas, and then for water distribution. The 100% PE policy of British Gas, and wide range of sizes used (at low...

2004 Milan : Design of Cylindrical Plastics Pipe Linings to Resist Buckling due to Collapse Pressures

Author(s) : Boot

Flexible (non-bonded) polymeric linings are used extensively to renovate both gravity and pressure pipes. Linings for both types of pipe are subject to collapse pressures, and in the case of gravity pipes this is the dominant source of loading; the efficient design of linings to sustain collapse pressures is therefore...

2004 Milan : The Above Ground Design of Plastic Pipe Systems for Process Fluids

Author(s) : MacKellar, Headford, Ingham

This paper provides an overview of the basic properties of plastic pipes, in the range 50mm to 400mm, and how these should be used in the design of above ground process pipe systems made of PE and PVC. It covers the basic properties of plastics, examples of the determination of load cases and describes the basic types...

2001 Munich : Butt Fusion Welding of Large Diameter/Thick Wall Pipes

Author(s) : Hill, Wilson, Headford

Butt fusion welding is the most reliable and unobtrusive method of joining PE pipes (and spigot fittings) of virtually any size-except perhaps the smallest where other methods are usually preferred. It is the dominant method of jointing both medium and large pipe sizes, but for different reasons. In medium pipe sizes...

1998 Gothenburg : Jointing Methods for Plastics Pipeline Systems

Author(s) : Headford

Jointing Methods for Plastics Pipeline Systems AL Headford (Durapipe S & LP, UK) ee Introduction The basic requirements for pipe Jointing are common to all pipe systems made from any material (including traditional materials), whether they be for sealed pressure usage or non-pressure usage. These are a) minimal...

1998 Gothenburg : Structural Considerations for Thermoplastic Pipe Linings Used for the Transport

Author(s) : Boot, Naqvi

The principles underlying the concept of thermoplastically lined pipes for untreated well-head fluids, with particular reference to subsea applications, are first described. The prime sources of load on the lining are then identified as build-up of gas pressure in the pipe-lining annulus and swell of the lining. Since...

1998 Gothenburg : The Structural Behaviour of Cured-In-Place Pipe

Author(s) : Boot, Javadi

The fundamental structural characteristics of cured-in-place pipe for sewer linings are first described, and current procedure for their design reviewed. Following identification of the major inconsistencies in this design philosophy, a programme of research with the objective of addressing these issues is summarised....

1995 Edinburgh : High Integrity PE Stub Flange Connections

Author(s) : Headford

A novel polyethylene stub flange adaptor is described which allows size-for-size connection, in terms of the respective bores, to iron pipes or fittings. The end load performance of this product is significantly superior to that achieved with conventional polyethylene flanges, especially at large pipe diameters, and...

1995 Edinburgh : Structural design of thin-walled PE pipe linings for water mains

Author(s) : Boot, Guan, Toropova

The Philosophy underpinning the concept of a polyethylene pipe lining designed to span small corrosion voids and longitudinal gaps in the host pipe is outlined, and provisional performance graphs for MDPE systems are given which indicate the potential savings that can be made under appropriate circumstances. Work...

1995 Edinburgh : The Resistance of PE Water Pipeline Systems to Surge Pressure

Author(s) : Beech, Headford, Hunt, Sandilands

The guldeUnes g h n in BS CP 312 :Pwt 2 : 1973 w e recommended to the UK toater industryfor the deslgn of polyethylene pfpeline systems to toke inin account the effects of tmnsient [surge) pressurejluctuatlons with respect to fatigue (ref.1). These guIdelInes we based on earlier experience wlth PVC-Usewer h i n g...

1992 Eindhoven : Structural Behaviour of Thin-Walled Plastic Pipe Linings for Water Mains

Author(s) : Boot, Guan

The case for development of rational design criteria for thinwalled polyethylene pipe linings is argued. Progress to date on a programme of research formulated to meet this objective is discussed. Short and long term behaviour under stress is modelled using elasto-plastic and elasto-viscoplastic constitutive models...

Members of the Association

BOREALISBOROUGEFormosa Plastics CorporationINEOS O&PIRPCKazanorgsintez PJSCKorea Petrochemical IND. Co., LTD (KPIC)LyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE
TOP