1 / 25

MINISTRY OF SCIENCE AND TECHNOLOGY YANGON TECHNOLOGICAL UNIVERSITY DEPARTMENT OF CIVIL ENGINEERING CE 3017 Highway and T

MINISTRY OF SCIENCE AND TECHNOLOGY YANGON TECHNOLOGICAL UNIVERSITY DEPARTMENT OF CIVIL ENGINEERING CE 3017 Highway and Traffic Engineering PRESENTER DAW KYAING LECTURER DEPARTMENT OF CIVIL ENGINEERING WEST YANGON TECHNOLOGICAL UNIVERSITY. Flexible Pavement Design AASHTO Design Method

lillian
Download Presentation

MINISTRY OF SCIENCE AND TECHNOLOGY YANGON TECHNOLOGICAL UNIVERSITY DEPARTMENT OF CIVIL ENGINEERING CE 3017 Highway and T

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MINISTRY OF SCIENCE AND TECHNOLOGY • YANGON TECHNOLOGICAL UNIVERSITY • DEPARTMENT OF CIVIL ENGINEERING • CE 3017 Highway and Traffic Engineering • PRESENTER • DAW KYAING • LECTURER • DEPARTMENT OF CIVIL ENGINEERING • WEST YANGON TECHNOLOGICAL UNIVERSITY

  2. Flexible Pavement Design • AASHTO Design Method • (American Association of State Highway and Transportation Officials)

  3. Design Considerations • Pavement Performance • Traffic • Roadbed Soils (Sub grade Material) • Materials of Construction • Environment • Drainage • Reliability

  4. Pavement Performance • Structural Performance • Related to physical condition (cracking, faulting, revealing • Functional Performance • How effectively the pavement serves the user (riding comfort) • Pavement Performance (Serviceability Performance) PSI  0 to 5 • Based on roughness & distress (cracking, patching, rut)

  5. Two Serviceability Indices • initial serviceability index (pi) • terminal serviceability index (pt) • Initial serviceability index (pi) • Serviceability index immediately after the construction of the pavement • pi = 4.2 (4.5 for good condition) (based on existing condition)

  6. terminal serviceable index (pt) • Based on class of highway • Pt = 2.5 or 3 (for major highway) • Pt= 2.0 (for lower class highway) • Pt = 1.5 (for economic constraints performance period may be reduced)

  7. Traffic • Traffic load  in terms of Equivalent 18000 lb Single Axial Load (ESALs)

  8. Roadbed Soils (Sub grade Material) for CBR of 10 or less Mr (lb/in2) = 1500 CBR for R of 20 or less Mr (lb/in2) = 1000+ 555xR value Mr = Resilient modulus

  9. Material of Construction • Quality of Material  • In terms of • Layer Coefficient , a • Sub base Construction Material a3 (from Fig. 20.15) • Base Course Construction Material a2 (from Fig. 20.16) • Surface Course Construction Material a1 (from Fig. 20.17) • (hot plant mix of AC & dense-graded agg. with max. size 1”)

  10. Environment • Temperature • Rainfall • Drainage • Drainage Factor, mi • Based on • % of time during which pavement str. nearly saturated & • Quality of Drainage

  11. Table 20.14 • Definition of Drainage Quality • Quality of Drainage Water Removed within • Excellent 2 hours • Good 1 day • Fair 1 week • Poor 1 month • Very Poor water will not drain

  12. Table 20.15 • Recommended mi Values • % of time pavement str. Is exposed to moisturelevels approaching saturation • Quality of drainageless than 1%1-5%5-25%greater than 25% • Fair 1.25-1.15 1.15-1.05 1.0-0.8 0.80

  13. Reliability (R %) • Depends on highway class & Region (T20.16) • ESAL based on assume growth rate • i.e may not be accurate • Other method do not consider this uncertainty • AASHTO consider reliability factor possible uncertainties in traffic condition performance prediction • 50 % Reliability design performance success is 50 % • Variation in traffic forecast

  14. Standard Deviation , So • Flexible pavement 0.4-0.5 • Rigid Pavement 0.3-0.4 • Table 20.16 • Suggested levels of reliability for various functional classification • Recommended Level of Reliability • Functional ClassificationUrbanRural • Interstate and other freeways 85-99.9 80-99.9

  15. Table 20.17 • Standard Normal Deviation (ZR) Values Corresponding to Selected Levels of Reliability • Reliability (R%) standard Normal Deviation ,ZR • 99 -2.327

  16. Structural Design • SN = a1D1+a2D2m2+a3D3m3 • D1,D2,D3 = actual thickness in inches of surface, base, & sub base course

  17. Example 20.8 • Given • Flexible Pavement • Urban Interstate Highway • ESAL = 2 x106 • a week for water to be drain with in moisture level = 30% • Mr of AC at 68 F = 45000psi • CBR value of base = 100, Mr = 31000psi • CBR value of sub base = 22, Mr = 13500psi • CBR of Sub grade = 6

  18. Solution • Reliability (R) = 99% (Table 20.16) • Standard Deviation (So) = 0.49 (0.4 - 05) • Pi = 4.5 • Pt = 2.5 • PSI = 4.5-2.5 = 2.0 a1 = 0.44 (Mr = 45000psi, AC) Fig. 20.17 a2 = 0.14 (CBR = 100,Base) Fig. 20.16 a3 = 0.1 (CBR = 22, sub base) Fig. 20.15 By using Figure 20.20, SN3 = 4.4 (Mr= 9000 psi) SN2 = 3.8 (Mr = 13500 psi) SN1 = 2.6 (Mr = 31000 psi)

  19. D1 = SN1/a1 =2.6/0.44 = 5.9” (use 6”) • D1* = 6” • SN1*= a1 D1* =0.44 x 6 = 2.64 • D2*≥ (SN2-SN1*)/(a2m2)≥(3.8-2.64)/(0.14x0.8) • ≥10.36’’ (Use 12’’) • SN2*= 0.14x0.8x12+2.64=1.34+2.64 =3.98 • D3* =(SN3-SN2*)/(a3m3)=4.4-(2.64+1.34)/(0.1x0.8) • = 5.25 ’’ (Use 6’’) • SN3*=2.64+1.34+6x0.8x0.1 = 4.46 • Asphalt concrete surface = 6” • Granular base = 12” • Sub base = 6”

  20. THE END

More Related