28 Pavement Design.ppt
- 1. PAVEMENT DESIGN USING CLIL METHODS CATHOLIC UNIVERSITY OF COLOMBIA 1
- 2. OBJECTIVES • UNDERSTAND AND COMPLETE THICKNESS CALCULATION BASED ON PREVIOUS CONCEPTS • KNOW VARIABLES INVOLVED IN AND BE ABLE TO CALCULATE REQUIRED THICKNESS OF RIGID AND FLEXIBLE PAVEMENTS 2
- 3. AASHTO PAVEMENT DESIGN METHOD CONSIDERATIONS • PAVEMENT PERFORMANCE • TRAFFIC • ROADBED SOIL • MATERIALS OF CONSTRUCTION • ENVIRONMENT • DRAINAGE • RELIABILITY • LIFE-CYCLE COSTS • SHOULDER DESIGN 3
- 4. TWO CATEGORIES OF ROADWAY PAVEMENTS • RIGID PAVEMENT • FLEXIBLE PAVEMENT RIGID PAVEMENT TYPICAL APPLICATIONS • HIGH VOLUME TRAFFIC LANES • FREEWAY TO FREEWAY CONNECTIONS • EXIT RAMPS WITH HEAVY TRAFFIC 4
- 5. ADVANTAGES OF RIGID PAVEMENT • GOOD DURABILITY • LONG SERVICE LIFE • WITHSTAND REPEATED FLOODING AND SUBSURFACE WATER WITHOUT DETERIORATION 5
- 6. DISADVANTAGES OF RIGID PAVEMENT • MAY LOSE NON-SKID SURFACE WITH TIME • NEEDS EVEN SUB-GRADE WITH UNIFORM SETTLING • MAY FAULT AT TRANSVERSE JOINTS 6
- 7. FLEXIBLE PAVEMENT TYPICAL APPLICATIONS • TRAFFIC LANES • AUXILIARY LANES • RAMPS • PARKING AREAS • FRONTAGE ROADS • SHOULDERS 7
- 8. ADVANTAGES TO FLEXIBLE PAVEMENT • ADJUSTS TO LIMITED DIFFERENTIAL SETTLEMENT • EASILY REPAIRED • ADDITIONAL THICKNESS ADDED ANY TIME • NON-SKID PROPERTIES DO NOT DETERIORATE • QUIETER AND SMOOTHER • TOLERATES A GREATER RANGE OF TEMPERATURES 8
- 9. DISADVANTAGES OF FLEXIBLE PAVEMENT • LOSES SOME FLEXIBILITY AND COHESION WITH TIME • NEEDS RESURFACING SOONER THAN PC CONCRETE • NOT NORMALLY CHOSEN WHERE WATER IS EXPECTED 9
- 10. BASIC AASHTO FLEXIBLE PAVEMENT DESIGN METHOD • DETERMINE THE DESIRED TERMINAL SERVICEABILITY, PT • CONVERT TRAFFIC VOLUMES TO NUMBER OF EQUIVALENT 18-KIP SINGLE AXLE LOADS (ESAL) • DETERMINE THE STRUCTURAL NUMBER, SN • DETERMINE THE LAYER COEFFICIENTS, AI • SOLVE LAYER THICKNESS EQUATIONS FOR INDIVIDUAL LAYER THICKNESS 10
- 11. BASIC AASHTO RIGID PAVEMENT DESIGN METHOD • SELECT TERMINAL SERVICEABILITY • DETERMINE NUMBER OF ESALS • DETERMINE THE MODULUS OF SUB-GRADE REACTION • DETERMINE THE SLAB THICKNESS 11
- 12. VARIABLES INCLUDED IN NOMOGRAPHS • RELIABILITY, R • INCORPORATES A DEGREE OF CERTAINTY INTO DESIGN PROCESS • ENSURES VARIOUS DESIGN ALTERNATIVES WILL LAST THE ANALYSIS PERIOD • RESILIENT MODULUS FOR ROADBED SOIL, MR • GENERALLY OBTAINED FROM LABORATORY TESTING 12
- 13. VARIABLES INCLUDED IN NOMOGRAPHS EFFECTIVE MODULUS OF SUB-GRADE REACTION, K •CONSIDERS: 1.SUB-BASE TYPE 2.SUB-BASE THICKNESS 3.LOSS OF SUPPORT 4.DEPTH TO RIGID FOUNDATION DRAINAGE COEFFICIENT, MI •USE IN LAYER THICKNESS DETERMINATION •APPLIES ONLY TO BASE AND SUB-BASE •SEE TABLES 20.15 (FLEXIBLE) AND 21.9 (RIGID) 13
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- 26. FLEXIBLE PAVEMENT DESIGN • PAVEMENT STRUCTURE IS A MULTI-LAYERED ELASTIC SYSTEM, MATERIAL IS CHARACTERIZED BY CERTAIN PROPERTIES • MODULUS OF ELASTICITY • RESILIENT MODULUS • POISSON RATIO • WHEEL LOAD CAUSES STRESS DISTRIBUTION (FIG 20.2) • HORIZONTAL: TENSILE OR COMPRESSIVE • VERTICAL: MAXIMUM ARE COMPRESSIVE, DECREASE WITH DEPTH • TEMPERATURE DISTRIBUTION: AFFECTS MAGNITUDE OF STRESSES 26
- 27. COMPONENTS 27 Sub-grade (roadbed) course: natural material that serves as the foundation of the pavement structure Sub-base course: above the sub-grade, superior to sub-grade course Base course: above the sub base, granular materials such as crushed stone, crushed or uncrushed slag, gravel, and sand Surface course: upper course of the road pavement, should withstand tire pressures, resistant to abrasive forces of traffic, provide skid- resistant driving surface, prevent penetration of surface water 3 inches to > 6 inches
- 28. ECONOMIC ANALYSIS • DIFFERENT TREATMENTS RESULTS IN DIFFERENT DESIGNS • EVALUATE COST OF DIFFERENT ALTERNATIVES 28
- 29. SENSITIVITY ANALYSIS • INPUT DIFFERENT VALUES OF TRAFFIC VOLUME • COMPARE RESULTING DIFFERENCES IN PAVEMENT • FAIRLY SIGNIFICANT DIFFERENCES IN ADT DO NOT YIELD EQUALLY SIGNIFICANT DIFFERENCES IN PAVEMENT THICKNESS 29
- 30. OTHER ISSUES • DRAINAGE • JOINTS • GROOVING (NOISE VS. HYDROPLANING) • RUMBLE STRIPS • CLIMATE • LEVEL AND TYPE OF USAGE 30
- 31. FAILURE EXAMPLES • PRIMARILY RELATED TO DESIGN OR LIFE-CYCLE, NOT CONSTRUCTION • ALL IMAGES FROM DISTRESS IDENTIFICATION MANUAL FOR THE LONG-TERM PAVEMENT PERFORMANCE PROGRAM, PUBLICATION NO. FHWA-RD-03-031, JUNE 2003 31
- 33. RUTTING 33
- 34. SHOVING 34
- 35. PUMPING 35