Vanuatu Rural Roads Design Guide Incorporating Climate Resilient Design Date of Report: June 2014 Version No: insertDate: number May 2017 Version No: 3.0 Public Works Department Vanuatu Rural Roads Design Guide Preamble The purpose of this Guide is to develop and promote appropriate methods of road engineering that gives the best possible access to rural communities at minimal cost. This Guide has been prepared for use across PWD for the rural road network in Vanuatu. The Public Works Department Standard Technical Specification for Road and Bridge Works and Standard Drawings are complementary documents addressing how the work shall be undertaken. They have been prepared as separate documents. This Guide does not include urban roads. The Austroads Road Design Series is the basis for this Vanuatu Rural Roads Design Guide. Rev 3.0 May 2017 Public Works Department | i Vanuatu Rural Roads Design Guide Document Control Document Owner: Sam Namuri, Director, Public Works Department Rev No. Date Revision Details Author Reviewer Approver 1.0 June 14 Original Roads for Development Ambatha P Sam Namuri 2.0 September 16 Reformatted Roads for Development Ambatha P Sam Namuri 3.0 May 2017 As per AHC Roads for Development R4D Junior comments George This document is issued by Public Works Department (PWD), a branch of the Ministry of Infrastructure and Public Works (MIPU) Approved by Junior Shim George Acting Director, Public Works Department Ministry of Infrastructure and Public Utilities This version 3.0 Rev 3.0 May 2017 Public Works Department | ii Vanuatu Rural Roads Design Guide Table of Contents Preamble...................................................................................................................................................i Document Control ..................................................................................................................................ii Table of Contents ..................................................................................................................................iii List of Figures ....................................................................................................................................... vi List of Tables ........................................................................................................................................ vi PART A - Design Guide for Geometry, Pavement and Drainage .......................................................1 1 Introduction .....................................................................................................................................1 2 Austroads Standard Guides ...........................................................................................................1 3 Methodology ....................................................................................................................................3 3.1 Road Network Description .........................................................................................................3 3.2 Approach to Design Standards ..................................................................................................3 4 Proposed Road Classification System .........................................................................................6 4.1 Road Function ............................................................................................................................6 4.2 Traffic Class ...............................................................................................................................6 4.3 Pedestrian Users ........................................................................................................................7 4.4 Terrain and Slopes .....................................................................................................................7 5 Guidelines to Geometric Design Standards .................................................................................8 5.1 Design Considerations ...............................................................................................................8 5.2 Design Speed .............................................................................................................................9 5.3 Terrain Considerations ............................................................................................................ 10 5.4 Cross Section Elements .......................................................................................................... 11 Width .................................................................................................................................. 11 Crossfall ............................................................................................................................. 13 5.5 Sight Distance Requirements ................................................................................................. 15 5.6 Vertical Curves ........................................................................................................................ 16 6 Guideline to Pavement Design ................................................................................................... 18 6.1 Pavement Requirements ........................................................................................................ 18 6.2 Pavement Development .......................................................................................................... 19 ........................................................................................................................................................ 19 6.3 Design Stages ......................................................................................................................... 19 Unformed Roads................................................................................................................ 19 Formed Roads ................................................................................................................... 19 Formed and paved (gravel) roads ..................................................................................... 19 Pavement Design .............................................................................................................. 20 Environment Factors ......................................................................................................... 21 Subgrade Evaluation ......................................................................................................... 22 Design Traffic Estimation ................................................................................................... 24 Pavement Thickness ......................................................................................................... 24 6.4 Selection of Pavement Material .............................................................................................. 25 Base / Wearing course material ........................................................................................ 25 7 Guidelines on Drainage Design .................................................................................................. 29 7.1 Overview ................................................................................................................................. 29 7.2 Internal and External Aspects of Drainage ............................................................................. 30 7.3 Permeability of Pavement Layers ........................................................................................... 31 7.4 Seepage and Subsurface Drains ............................................................................................ 31 7.5 External Drainage ................................................................................................................... 31 7.6 Surface Drainage .................................................................................................................... 32 7.7 Crossfall and Shoulders .......................................................................................................... 32 ........................................................................................................................................................ 33 ........................................................................................................................................................ 33 Rev 3.0 May 2017 Public Works Department | iii Vanuatu Rural Roads Design Guide 7.8 Crown Height .......................................................................................................................... 33 7.9 Road Elevation ........................................................................................................................ 34 7.10 Table Drains ...................................................................................................................... 34 In-sloping ....................................................................................................................... 34 Out-sloping .................................................................................................................... 35 V-shaped and Trapezoidal Drains ................................................................................. 36 7.11 Cut-off (or Mitre) Drains ..................................................................................................... 37 7.12 Cross Drains 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