FLEXIBLE PAVEMENT DESIGN MANUAL OFFICE OF DESIGN, PAVEMENT MANAGEMENT SECTION JANUARY 2018 TALLAHASSEE, FLORIDA Topic #625-010-002 Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 TABLE OF CONTENTS Chapter/Section Title Page No. 1.0 INTRODUCTION 1-1 1.1 PURPOSE 1-1 1.2 AUTHORITY 1-1 1.3 GENERAL 1-1 1.4 SCOPE 1-2 1.5 FLEXIBLE PAVEMENT DESIGN MANUAL 1-2 ORGANIZATION AND REVISIONS 1.5.1 References 1-2 1.5.2 Florida Conditions 1-2 1.5.3 Appendices 1-3 1.6 DISTRIBUTION 1-4 1.7 PROCEDURE FOR REVISIONS & UPDATES 1-4 1.8 TRAINING 1-5 1.9 FORMS 1-5 2.0 DEFINITIONS 2-1 2.1 PAVEMENT SYSTEM 2-1 2.2 AASHTO DESIGN EQUATION 2-4 2.2.1 Variables 2-4 2.2.2 Constants 2-6 2.2.3 Unknowns 2-7 2.3 TERMS 2-7 3.0 PAVEMENT THICKNESS DESIGN PROCESS 3-1 3.1 DESIGN SOURCE 3-1 3.2 DESIGN PERIODS 3-5 3.3 DISTRICT COORDINATION 3-5 3.4 QUALITY 3-6 3.5 GUIDELINES FOR DESIGN/BUILD PROJECTS 3-6 4.0 FRICTION COURSE POLICY 4-1 4.1 FRICTION COURSE OPTIONS 4-1 Table of Contents i Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 Chapter/Section Title Page No. 4.2 FRICTION COURSES 12.5 AND 9.5 (FC-12.5 and 4-3 FC-9.5) 4.3 FRICTION COURSE 5 (FC-5) 4-3 5.0 PAVEMENT THICKNESS DESIGN PROCESS 5-1 FOR NEW CONSTRUCTION or RECONSTRUCTION 5.1 OVERVIEW 5-1 5.2 REQUIRED STRUCTURAL NUMBER (SNR) 5-1 CALCULATIONS USING THE AASHTO DESIGN GUIDE 5.2.1 Design Example 5-2 5.2.2 Design Base Highwater Clearance 5-3 5.2.3 Laboratory Resilient Modulus (MR) 5-4 5.2.4 Resilient Modulus (MR) From LBR 5-6 5.3 LAYER THICKNESS CALCULATIONS FOR 5-11 NEW CONSTRUCTION 5.4 BINDER SELECTION ON THE BASIS OF TRAFFIC 5-12 SPEED AND TRAFFIC LEVEL 5.5 NEW CONSTRUCTION DESIGN SAMPLE 5-19 PROBLEM 5.6 DESIGN CONSIDERATIONS 5-24 5.6.1 Stabilized Subgrade 5-24 5.6.2 Base 5-25 5.6.3 Asphalt Base Curb Pad 5-27 5.6.4 Structural Course 5-27 5.6.5 Traffic Levels 5-28 5.6.6 Layer Thickness 5-28 5.6.7 Ramp Design 5-33 6.0 PAVEMENT WIDENING 6-1 6.1 REQUIREMENTS 6-1 6.2 STRUCTURAL COURSE 6-1 6.3 BASE AND SUBGRADE 6-3 6.4 STABILIZATION 6-3 6.5 LABORATORY RESILIENT MODULUS (MR) 6-3 6.6 WIDENING DESIGN SAMPLE PROBLEM 6-4 Table of Contents ii Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 Chapter/Section Title Page No. 7.0 PAVEMENT THICKNESS DESIGN PROCESS 7-1 FOR REHABILITATION PROJECTS 7.1 OVERVIEW 7-1 7.2 REQUIRED STRUCTURAL NUMBER (SNR) 7-1 CALCULATIONS USING THE AASHTO DESIGN 7.3 RESILIENT MODULUS (MR) VARIATIONS 7-1 7.3.1 Resilient Modulus (MR) From 7-3 Nondestructive Testing 7.3.2 Resilient Modulus (MR) From LBR 7-3 7.4 EVALUATING THE EXISTING STRUCTURAL 7-7 NUMBER (SNE) 7.4.1 Field Testing 7-7 7.4.2 Data Collection 7-7 7.4.3 Pavement Evaluation 7-8 7.4.4 Reduced Layer Coefficients 7-9 7.5 MILLING 7-12 7.5.1 Candidate Projects 7-12 7.5.2 Pavement Coring and Sampling 7-13 7.5.3 Variable Depth Milling 7-13 7.5.4 Cross Slope 7-13 7.5.5 Rutted Pavement 7-14 7.5.6 Milling Depth 7-14 7.6 CALCULATING THE STRUCTURAL OVERLAY 7-15 NUMBER (SNO) 7.7 OVERLAY DESIGN SAMPLE PROBLEM 7-15 7.8 SPECIAL CONSIDERATIONS FOR 7-19 REHABILITATION PROJECTS 7.8.1 Payment of Structural Course 7-19 7.8.2 Overbuild 7-19 7.8.3 Operational Projects 7-20 7.8.4 Functional Overlays 7-20 7.8.5 Crack Relief Layers 7-21 8.0 SHOULDER DESIGN 8-1 8.1 DESIGN GUIDANCE 8-1 Table of Contents iii Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 APPENDICES Appendix Title Page No. A.0 DESIGN TABLES A-1 A.1 INSTRUCTIONS A-1 B.0 FLEXIBLE PAVEMENT DESIGN QUALITY B-1 CONTROL PLAN B.1 QUALITY CONTROL PLAN B-1 B.2 DEFINITIONS B-1 B.3 RESPONSIBILITY B-2 B.4 FLEXIBLE PAVEMENT DESIGNS B-2 B.4.1 Minimum Requirements B-2 B.4.2 Distribution B-3 B.4.3 Revisions B-4 B.4.4 Documentation B-5 B.5 DISTRICT QUALITY CONTROL B-5 B.6 QUALITY ASSURANCE REVIEWS B-6 B.7 PAVEMENT DESIGN UPDATES B-6 Flexible Pavement Design Quality Control B-7 Checklist Florida Department of Transportation B-10 Flexible Pavement Design Summary Sheet C.0 MECHANISTIC-EMPIRICAL PAVEMENT C-1 DESIGN GUIDE D.0 ESTIMATING DESIGN 18-KIP EQUIVALENT D-1 SINGLE AXLE LOADS (ESALD) D.1 BACKGROUND D-1 D.2 BASIC EQUATION D-3 D.3 SAMPLE PROBLEMS D-6 D.3.1 Sample Problem #1 D-6 D.3.2 Sample Problem #2 D-9 Table of Contents iv Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 FIGURES Figure Title Page No. 2.1 ROADWAY TYPICAL SECTION 2-3 3.1 AASHTO DESIGN EQUATION for 3-2 FLEXIBLE PAVEMENT 3.2 AASHTO DESIGN EQUATION INPUT for 3-3 FLEXIBLE PAVEMENT 3.3 FLEXIBLE PAVEMENT DESIGN VARIABLES 3-4 4.1-4.2 ILLUSTRATIONS SHOWING LIMITS of 4-6 - FRICTION COURSE-5 (FC-5) at 4-7 INTERMEDIATE MEDIAN CROSSOVER 4.3 ILLUSTRATION SHOWING LIMITS of 4-8 FRICTION COURSE-5 (FC-5) at MEDIAN AREAS of LOW VOLUME INTERSECTIONS 5.1 10% MR METHOD ILLUSTRATION 5-5 6.1 WIDENING DETAIL for SAMPLE PROBLEM 6-7 7.1 FLEXIBLE PAVEMENT REHABILITATION 7-2 PROCESS 7.2-7.4 EXAMPLE DEFLECTION PLOTS 7-4 - 7-6 Table of Contents v Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 TABLES Table Title Page No. 3.1 DESIGN PERIODS 3-8 4.1 FRICTION COURSE SELECTION 4-3 5.1 RELATIONSHIP BETWEEN RESILIENT 5-8 MODULUS (MR) and LIMEROCK BEARING RATIO (LBR) SAMPLE VALUES 5.2 RELIABILITY (%R) for DIFFERENT ROADWAY 5-9 FACILITIES 5.3 EXAMPLE DESIGN TABLE (FROM 5-10 APPENDIX A, TABLE A.4A) 5.4 STRUCTURAL COEFFICIENTS for DIFFERENT 5-14 PAVEMENT LAYERS (NEW CONSTRUCTION or RECONSTRUCTION) 5.5 REQUIRED MINIMUM THICKNESS for NEW 5-15 CONSTRUCTION or RECONSTRUCTION 5.6 GENERAL USE OPTIONAL BASE GROUPS 5-16 and STRUCTURAL NUMBERS 5.7 LIMITED USE OPTIONAL BASE GROUPS 5-17 and STRUCTURAL NUMBERS 5.8 GENERAL NOTES FOR OPTIONAL BASE 5-18 GROUPS and STRUCTURAL NUMBERS 5.9 COMBINED STRUCTURAL NUMBER 5-23 Table of Contents vi Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 TABLES (CONTINUED) Table Title Page No. 5.10 DESIGN NOTES ON LAYER THICKNESS FOR 5-31 ASPHALT CONCRETE STRUCTURAL COURSES 5.11 LAYER THICKNESS FOR ASPHALTIC CONCRETE 5-32 STRUCTURAL COURSES 7.1 REDUCED STRUCTURAL COEFFICIENTS of 7-11 ASPHALT MATERIALS PER INCH 7.2 AASHTO SUGGESTED LAYER COEFFICIENT 7-12 FOR FRACTURED SLAB PAVEMENT A.1A- REQUIRED STRUCTURAL NUMBER (SNR) A-3 - A.10B A-22 D.1 RELATIONSHIP of AXLE WEIGHT TO D-2 DAMAGE D.2 LANE FACTORS (LF) FOR DIFFERENT TYPES D-4 of FACILITIES D.3 EQUIVALENCY FACTORS E18 FOR DIFFERENT D-5 TYPES of FACILITIES DESIGN AIDS Title Page No. FLEXIBLE PAVEMENT DESIGN QUALITY CONTROL B-7 CHECKLIST FLORIDA DEPARTMENT OF TRANSPORTATION B-10 FLEXIBLE PAVEMENT DESIGN SUMMARY SHEET Table of Contents vii Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 FLEXIBLE PAVEMENT DESIGN MANUAL CHAPTER 1 INTRODUCTION 1.1 PURPOSE The objective of this manual is to provide a Pavement Design Engineer with sufficient information so that the necessary input data can be developed and proper engineering principles applied to design a new flexible pavement, or develop a properly engineered pavement rehabilitation project. This design manual addresses methods to properly develop a pavement rehabilitation project, pavement milling, and the computations necessary for the pavement design process. It is the responsibility of the Pavement Design Engineer to ensure that the designs produced conform to Department policies, procedures, standards, guidelines, and sound engineering practices. 1.2 AUTHORITY Sections 20.23(3) (a) and 334.048(3), Florida Statutes 1.3 GENERAL Chapter 334 of the Florida Statutes, known as the Florida Transportation Code, establishes the responsibilities of the state, counties, and municipalities for the planning and development of the transportation systems serving the people of the State of Florida, with the objective of assuring development of an integrated, balanced statewide system. Introduction 1-1 Topic #625-010-002 Effective: March 15, 2008 Flexible Pavement Design Manual Revised: January 2018 The Code's purpose is to protect the safety and general welfare of the people of the State and to preserve and improve all transportation facilities in Florida. Section 334.148(3), Florida Statutes, sets forth the powers and duties of the Department of Transportation to develop and adopt uniform minimum standards and criteria for the design, construction, maintenance, and operation of public roads.