1. 3 rd REVISION OF TRH12 Renaldo Lorio 12 th Meeting of RPF - 8 November 2006

2. History of TRH12 Road rehabilitation research work started circa 1980 Road rehabilitation research work started circa 1980 TRH12 appear in 1983 TRH12 appear in 1983 1 st revision in 1990/1 1 st revision in 1990/1 2 nd revision 1997 (minor alterations) 2 nd revision 1997 (minor alterations) 3 rd revision 2005/6 3 rd revision 2005/6

3. Third revision Need identified during 2003 Need identified during 2003 Obtained comments from individuals Obtained comments from individuals Workshops Workshops SANRAL committed funds SANRAL committed funds Established committee in 2005 Established committee in 2005

4. Committee Renaldo LorioSANRAL Renaldo LorioSANRAL Kobus van der WaltSANRAL Kobus van der WaltSANRAL Gerrit JordaanTshepega Gerrit JordaanTshepega Ian van WijkAfricon Ian van WijkAfricon Philip JoubertSSI Philip JoubertSSI Fritz JoosteM&A Fritz JoosteM&A Kim JenkinsUS Kim JenkinsUS Johan HattinghPHI Johan HattinghPHI Bryan PerrieC&CI Bryan PerrieC&CI Andre Molenaar TU Delft - Moderator Andre Molenaar TU Delft - Moderator

5. Overview of comments Generally acceptable procedure Generally acceptable procedure TRH12 more a textbook than a guideline document TRH12 more a textbook than a guideline document Clear guidelines and procedures required Clear guidelines and procedures required Accuracy / correctness of criteria related to deflection measurements (different devices) Accuracy / correctness of criteria related to deflection measurements (different devices) Relevance of AI, TRRL and Shell overlay design Relevance of AI, TRRL and Shell overlay design Changes in traffic loading predictions Changes in traffic loading predictions

6. Overview of comments Design reliability concept and how to cater for variability Design reliability concept and how to cater for variability Improve readability and provide examples Improve readability and provide examples

7. Objectives Define process more clearly Define process more clearly Provide more definitive guidelines with explanatory appendices Provide more definitive guidelines with explanatory appendices Repackage to make clearer – include relevant available information Repackage to make clearer – include relevant available information Improve on some definitions Improve on some definitions Add examples Add examples Tendering for consultant services

8. Revision process Three step approach Three step approach 1.Based on comments received prepare first draft – Review first draft 2.Based on review prepare second draft – Review second draft 3.Prepare third draft – Final review and finalization

9. Project phases Initial Assessment Detailed Assessment Preliminary Design Detail Design Procurement Documents Present Detailed Assessment Investigation and Analysis = Evaluation Rehabilitation Design IARDARPDRDRIR Fact finding / diagnosisDecision makingFinalisation TD Initial assessment Detail design 1997 2006 TRH12

10. Most significant changes to date Do away with “remaining life” / “end of life concepts” - replacement not clear as yet but will be related to the functionality of the pavement Do away with “remaining life” / “end of life concepts” - replacement not clear as yet but will be related to the functionality of the pavement Relook at the design reliability concepts – needs revision but not sure what the answer is as yet Relook at the design reliability concepts – needs revision but not sure what the answer is as yet

11. Most significant changes to date Provide definitions for short, medium and long term Provide definitions for short, medium and long term Do away with deflection criteria as in Appendix 1 of 1997 version - misuse Do away with deflection criteria as in Appendix 1 of 1997 version - misuse –Rather focus on relative differences –Include well know “Cusum” plots

12. Most significant changes to date Provide guidelines for the provision of a detailed test plan Provide guidelines for the provision of a detailed test plan –What information is needed ? –How is it to be obtained – take account of variability –How is it to be used ? Provide guidelines to collate information to be exported to other design methods – most notably SAMDM Provide guidelines to collate information to be exported to other design methods – most notably SAMDM

13. Most significant changes to date Inclusion of concrete (rigid pavement) solutions where appropriate Inclusion of concrete (rigid pavement) solutions where appropriate Possibility of reviving SABITA’S REACT software to be used in economic appraisal of various remedial options Possibility of reviving SABITA’S REACT software to be used in economic appraisal of various remedial options Literature referred to in the text will be provided on a CD as far as copy right restrictions provide Literature referred to in the text will be provided on a CD as far as copy right restrictions provide

14. Thank you