DEVELOPMENT OF METHODOLOGY TO ESTIMATE ESAL VAULES FOR LOW VOLUME ROADS IN PROVINCIAL SECTOR G J Kinigama (08/8862) Degree of Master of Engineering Department of Civil Engineering University of Moratuwa March 2010 DEVELOPMENT OF METHODOLOGY TO ESTIMATE ESAL VALUES FOR LOW VOLUME ROADS IN PROVINCIAL SECTOR G J Kinigama (08/8862) Dissertation submitted in partial fulfillment of the requirement for the Degree of Master of Engineering in Highway & Traffic Engineering Department of Civil Engineering University of Moratuwa Sri Lanka March 2010 i DECLARATION “I declare that this is my own work and this dissertation does not incorporate without acknowledgement any material previously submitted for a Degree or Diploma in any University or other institution of higher learning and to the best of my knowledge and belief it does not contain any material previously published or written by another person except where the acknowledgement is made in the text” Signature: Date: “I have supervised and accepted this thesis for the submission of the degree” Signature of the supervisor: Date: ii ACKNOWLEDGEMENT I take this opportunity to express my gratitude to everyone who has been instrumental in the successful completion of this project. I would like to express the deepest appreciation to my supervisor, Dr. W K Mampearachchi, without his guidance and persistent help this dissertation would not have been possible. I would like to express my greatest appreciation to Prof. J M S J Bandara and Prof. Amal S. Kumarage for their valuable ideas, knowledge and training provided during the study period to carry out a research project of this nature. I extend many thanks to Deputy Director (Planning -2) – Ms D A Pushpa Padmini and Engineer Ms D H S D A Siriwardhana for providing traffic data and other information required for this study. I also thank Mr. Y Yamasita and other team members of JBIC funded Provincial Roads Improvement Project for their valuable co-operation for permitting the use of design reports and traffic data. My sincere thanks extended to Mr. R P Nanayakkara and other members of my office for the valuable ideas and assistance given to me for the completion of this project. I also thank the staff members of Traffic Engineering Division of Civil Engineering Department for their assistance. Finally I appreciate the support and encouragement given by my wife and two daughters for being patient with their time while I was working on this research work. iii ABSTRACT The demands for the improvement of provincial roads are ever increasing and GOSL has given priority for the upliftment of rural economy through the improvement of rural road network. Funding agencies have shown interest in providing financial assistance for this task. Road design engineers require reliable traffic data and design specifications for detailed design of provincial roads. One of the basic inputs required for the pavement design is the ESAL values for each vehicle category in each road. The most common method used for the estimation of ESAL values for trucks is the static axle load survey conducted by RDA for national roads. The axle load surveys are rarely done for provincial roads. Different approaches have been adopted for the estimation of truck factors for provincial roads. Lack of institutional arrangements, inadequacy of funds, lack of technical knowledge and equipment are the main reasons for the inability to carry out proper studies in this sector. Currently used axle load survey methods and their errors are being discussed under literature review. A simple but accurate methodology is required for the estimation of axle loads. The main objective is to find out ¾ How to estimate the truck loads from visual observation ¾ Then how this load is distributed among the axles A good vehicle classification system is highly desirable for provincial road network in order to find out ESAL values. The vehicle load can be estimated using first principles. The historical axle load survey data shall be used to derive a relationship for the distribution of vehicle load between axles. Then the results will be used for the estimation of ESAL for a sample road. The analysis of results will be done with probability approach. The results will also be checked and verified for accuracy and reliability. Actual axle load survey data will be used for this verification. A simple yet very effective method for the estimation of truck factors shall be introduced for the provincial roads. Most of the provincial road agencies can use this method to find out ESAL values for the entire road network with the available resources. Further recommendations will be made for further improvements on the methodology to improve the reliability of result. iv TABLE OF CONTENTS Declaration i Acknowledgement ii Abstract iii Table of Contents iv List of Tables vi List of Figures vii CHAPTER 1: INTRODUCTION .............................................................................1 1.1 Background ....................................................................................................1 1.2 Problem Statement .........................................................................................2 1.3 Research Objectives and Principals ...............................................................3 1.4 Outline of the Thesis ......................................................................................4 CHAPTER 2: LITERATURE REVIEW ..................................................................5 2.1 Introduction to Traffic Data Collection .........................................................5 2.2 Vehicle Definitions ........................................................................................6 2.3 Vehicle Classifications...................................................................................7 2.4 Definitions of Terminologies.........................................................................8 2.5 Methods of Traffic Counts...........................................................................10 2.5.1 Manual counts......................................................................................10 2.5.2 Axle sensor based counters (pneumatic tube systems) ........................11 2.5.3 Vehicle length based counters .............................................................13 2.5.4 Machine vision based equipment.........................................................14 2.5.5 Other technologies ...............................................................................15 2.6 Damage to Pavements by Loaded Vehicles................................................15 2.7 Load Spreading to a Pavement ...................................................................16 2.8 Magnitude and Effect of Load ....................................................................17 2.9 Pavement Deterioration ..............................................................................18 2.10 Axle Load Weighing Systems .....................................................................19 2.10.1 Portable wheel or axle weighing units .................................................19 2.10.2 On-board weighing system ..................................................................20 2.10.3 Single axle weighbridge.......................................................................20 v 2.10.4 Full length plate weighbridge ..............................................................20 2.10.5 Part length weighbridge .......................................................................21 2.11 Overview of Vehicle Weighing Methods ....................................................21 CHAPTER 3: METHODOLOGY ..........................................................................30 3.1 Introduction..................................................................................................30 3.2 Vehicle Composition on Rural Rroads ........................................................31 3.3 Vehicle Classification ..................................................................................38 3.4 Estimation of Axle Loads ............................................................................39 3.5 The Distribution of Vehicle Load among Axles..........................................44 CHAPTER 4: ANALYSIS OF DATA AND RESULTS........................................49 4.1 Data Collection ............................................................................................49 4.1.1 Manual classified counts......................................................................49 4.1.2 Axle load survey on national highways ...............................................50 4.1.3 Axle Load survey on provincial roads by RDA...................................51 4.1.4 Axle load survey with loading condition and vehicle dimensions ......52 4.2 Analysis of Data……………………………………………………...53 4.2.1 Load distribution among axles.............................................................53 CHAPTER 5: ANALYSIS AND VERIFICATION OF RESULTS......................67 5.1 Results..........................................................................................................67 5.1.1 Distribution of empty truck loads among axles ...................................67 5.1.2 Distribution of truck loads among axles ..............................................68 5.2 Analysis of Results ......................................................................................72 5.3 Verification of Results .................................................................................79 CHAPTER 6: CONCLUSION AND RECOMMENDATIONS ............................81 6.1 Conclusion ...................................................................................................82 6.2 Recommendations........................................................................................83 References:...................................................................................................................85 Appendix A…………………………………………………………………………. 86 Appendix B…………………………………………………………………………..89 Appendix C………………………………………………………………………….149 Appendix D…………………………………………………………………………159 vi LIST OF TABLES Table 2.1 Standard Vehicle Classification System ...................................................7 Table 3.1 Road List .................................................................................................32 Table 3.2 Traffic Composition................................................................................34 Table 3.3 Vehicle Classification System for Provincial Roads ..............................39 Table 3.4 Axle Load Survey Data for Empty Light Goods vehicles ......................41 Table 3.5 Validated Data for Empty Truck Loads of LGV ....................................42 Table 3.6 Loading Conditions.................................................................................44 Table 3.7 Axle Load Data for Loaded Trucks of LGV...........................................45 Table 3.8 Validated Axle Data for Loaded LGV....................................................47 Table 4.1 MCC Data on Nawalapitiya Dekinda Road............................................49 Table 4.2 List of National Roads – Axle Survey Locations ...................................50 Table 4.3 List of Provincial roads -Axle Load Survey by RDA.............................52 Table 4.4 Axle Load Survey Data with Vehicle Dimensions .................................52 Table 4.5 Vehicle Grouping Between RDA and Provincial roads .........................54 Table 4.6 Load Distribution Analysis-Empty Large Bus .......................................55 Table 4.7 Load Distribution Analysis-Empty Medium Bus ...................................56 Table 4.8 Load distribution Analysis- Empty LGV................................................56 Table 4.9 Load distribution Analysis – Empty MGV.............................................57 Table 4.10 Load distribution Analysis – Empty LGV..............................................57 Table 4.11 Load Distribution Analysis- FV..............................................................58 Table 4.12 Load Distribution Analysis - Large Bus .................................................58 Table 4.13 Load Distribution Analysis- Medium Bus..............................................59 Table 4.14 Load Distribution Analysis- LGV ..........................................................59 Table 4.15 Load Distribution Analysis- Arrack/Beer...............................................60 Table 4.16 Load Distribution Analysis- Asphalt ......................................................61 Table 4.17 Load Distribution Analysis- Blasting Material.......................................61 Table 4.18 Load Distribution Analysis- Bricks ........................................................62 Table 4.19 Load Distribution Analysis - Cement .....................................................62 Table 4.20 Load Distribution Analysis- Arrack/Beer...............................................63 Table 4.21 Load Distribution Analysis- Ceramics....................................................63 Table 4.22 Load Distribution Analysis- Electric Posts.............................................64 Table 4.23 Load Distribution Analysis- Fruits .........................................................64 vii Table 4.24 Load Distribution Analysis- Motor Spare Parts......................................65 Table 4.25 Load Distribution Analysis- Water.........................................................65 Table 4.26 Load Distribution Analysis- Farm Tractors............................................66 Table 5.1 Load distribution Ratios-Empty trucks...................................................68 Table 5.2 Load Distribution Ratios-Loaded Trucks ...............................................69 Table 5.3 Load Distribution Ratios-Loaded Medium Goods Vehicles ..................69 Table 5.4 Load Distribution Ratios-Loaded Heavy Goods Vehicles......................71 Table 5.5 Standard Deviation Values – Empty Trucks...........................................73 Table 5.6 Standard Deviation Values –Large Buses...............................................74 Table 5.7 Standard Deviation Values –Medium Buses ..........................................74 Table 5.8 Standard Deviation Values –Medium Buses ..........................................75 Table 5.9 Standard Deviation Values –Medium Goods Vehicles ..........................76 Table 5.10 Standard Deviation Values –Medium Goods Vehicles ..........................78 Table5.11 ESAL Values for Provincial Roads ........................................................80 Table 5.12 ESAL values on Padiyatalawa-Mahiyangana Road ...............................81 viii LIST OF FIGURES Figure 2.1 Loads Spreading on a Pavement .............................................................17 Figure 2.2 Three Groups of Heavy Vehicles with Equal Damaging Effect.............18 Figure 2.3 Effect of Width in Wheel Base ...............................................................22 Figure 2.4 Effect of Weight Transfer-Three Wheel Base ........................................23 Figure 2.5 Weighing on a Level Plane .....................................................................23 Figure 2.6 Load Transfer on Flat Ground ................................................................24 Figure 2.7 Load Transfer on an Inclined Surface.....................................................24 Figure 2.8 The Distribution of Load within the Truck.............................................25 Figure 3.1 Traffic Composition on Nawalapito\iya – Dekinda Road ......................35 Figure 3.2 Major and Minor Traffic Distribution ....................................................36 Figure 3.3 Distribution of Heavy & Light vehicles .................................................36 Figure 3.4 Heavy Vehicle Composition ...................................................................37 Figure 3.5 Heavy and Light Vehicle Distribution....................................................37 Figure 3.6 Axle Load Distributions for Empty Trucksof LGV................................42 Figure 3.7 Load Distribution among Axles for Loaded Trucks ...............................48