ISO/TS TECHNICAL SPECIFICATION 20656-1 First edition 2017-06 Plastics piping systems General rules for structural design of glass reinforced thermosetting plastics (GRP) pipes - Part 1: Buried pipes Systemes de canalisation en matieres plastiques - Regles générales pour la conception structurelle des tubes et raccords plastiques thermodurcissables renforces de verre (PRV) - Partie 1: Tubes enterré Reference number IS0/TS 20656-1:2017(E) International Organization for Standardization @ IS0 2017 ed without license from IHS IS0/TS 20656-1:2017(E) COPYRIGHT PROTECTEDDOCUMENT IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org Licensee-ZHEJIANG INST OF STANDARDIZAISQ 07 - All rights reserved Not for Resale, 2017/9/12 03:14:00 networking permited without license from IHS IS0/TS 20656-1:2017(E) Contents Page Foreword ..iv Introduction.. ..V 1 Scope. 2 Normative references 3 Terms and definitions 4 Partial factor method. ..2 4.1 General .2 4.2 Reliability index, β. ..2 4.3 Sensitivity index, a.. .4 4.4 Quality management ..4 5 Partial factors for effects of actions .5 5.1 General .5 5.2 Partial factors for internal pressure ..5 5.2.1 General. 5 5.2.2 Model uncertainty .6 5.2.3 Uncertainty of pressure 7 5.2.4 Uncertainty of long-term pressure .7 5.2.5 Uncertainty of short-term pressure .8 5.2.6 Uncertainty of thickness and E-modulus 9 5.2.7 Uncertainty of diameter .. .9 5.2.8 Combined uncertainty and partial factor for effects of pressure .9 5.3 Partial factors for soil and traffic load .12 5.3.1 General. .12 5.3.2 Uncertainty of installation parameters .14 5.3.3 Uncertainty of deflection model ..14 5.3.4 Uncertainty in traffic load. .15 5.3.5 Uncertainty in pipe stiffness. ..15 5.3.6 Uncertainty of deflection measurement. .15 5.3.7 Deflection iag factor. .15 5.3.8 Uncertainty of model - Stress and strain calculation .15 5.3.9 Strain assessment through curvature measurement ..16 5.3.10 Combined uncertainty of installation parameters ..16 5.3.11 Partial factors for effects of bending ..16 5.4 Combined effects of pressure and bending. ..17 6 Partial factors for resistance ..17 6.1 Concept ..17 6.2 Design value for resistance .18 6.2.1 General 6.2.2 Long-term resistance and conversion factor, n 6.2.3 Short-term resistance. ..19 Annex A (normative) Recommended values for pressure safety factors ..21 Annex B (normative) Test data analysis. ..22 Bibliography .24 ii icensee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 ted without license from IHS