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Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
LecturerDr. Eng. Omar Osman
Asst. Professor of Highway & Airport EngineeringFaculty of Engineering, Cairo University
CAIRO UNIVERSITY FACULTY OF ENGINEERINGPUBLIC WORKS DEPARTMENT
Structural Design of Pavements
4th Year Civil Engineering Highway Engineering Course2008-2009
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
Structural Design of Pavements
II- Rigid Pavements
- Materials
- Stresses
- Design Methods
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
Pavement Types
- Flexible
- Rigid
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
Factors Influencing Pavement Design/Performance
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
Cracks
Corner Breaks Joint Failure
Faulting
Critical Concrete Pavement Responses: Distresses
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
RIGID PAVEMENT TYPES
a) Simply Reinforced
b) doweled
c) plain
d) skewed joints
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
JOINT TYPES
• Expansion:
• Doweled Contraction:
• Keyed Construction:
• Doweled Construction:
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
JOINT TYPES
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
STRUCTURAL SYSTEM
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
• SUBGRADE SUPPORT
• Modulus of Subgrade Reaction: k (pci)
STRUCTURAL SYSTEM
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
• Radius of Relative Stiffness
STRUCTURAL SYSTEM
[50~500 pci][0.15]
[4,000,000 psi][8~24 inch]
[25~98 inch]
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
STRESSES IN RIGID PAVEMENTS –Temperature: Warping Stresses
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
Temperature: Warping Stresses
[2~3 ºF/inch][0.000005]
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
Temperature: Warping Stresses
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
STRESSES IN RIGID PAVEMENTS –Temperature: Friction Stresses
[1.5]
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
Temperature: Friction Stresses –Slab Length
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
STRESSES IN RIGID PAVEMENTS –Loading
Wheel Loads& Stresses
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
STRESSES IN RIGID PAVEMENTS –Loading Cases
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
STRESSES IN RIGID PAVEMENTS –Loading Stresses
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
STRESSES IN RIGID PAVEMENTS –Loading Stresses
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Design Method
• Design Considerations:• Flextural Strength of Concrete• Subgrade & Subbase Support• Traffic Load
• Design Procedure:• Finite-element analysis: Stresses & Deflections• Fatigue analysis (crack initiation)• Erosion analysis (Pumping, Faulting)
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Design Method
• Flextural Strength of Concrete (modulus of rupture)
ASTM C78 – Third-point methodP × L / (w d2)
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Design Method
• Subgrade Characterization
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Design Method•Subbase Support: Correction of Modulus of sub grade reaction (K)
associated with agg. subbase thickness.
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Design Method• Traffic
• Load factors• Interstate: 1.2• Arterial: 1.1• Local access: 1.0
• Axle configuration and loads: Classes & Counts
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Design Method• Fatigue analysis
• To limit fatigue cracking (initiation of first crack)• Determine equivalent stress associate with sub grade reaction and
pavement thickness• Determine stress ratio = equivalent stress/MOR • Determine allowable number of stress application at the given axel
load and stress ratio• Repeat for all axel loads• Calculate the % fatigue life used for each applied load. The sum
for all loads must be less then 100%.
• Erosion analysis• Basically the same method is used as in the fatigue analysis.
Limiting corner deflections is the target.
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Fatigue Analysis, Equiv. Stress; No Shoulder
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Fatigue Analysis, Equiv. Stress; With Shoulder
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Fatigue Analysis, Allowable Repetitions
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Erosion Analysis, Erosion Factor; Doweled No Shoulder
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Erosion Analysis, Erosion Factor; Agg Interlock No Shldr
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Erosion Analysis, Erosion Factor; Doweled & Shoulder
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Erosion Analysis, Erosion Factor; Agg Interlock & Shldr
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Erosion Analysis, Allowable Repetitions –No Shoulder
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method – Erosion Analysis, Allowable Repetitions –With Shoulder
Highway Engineering - Structure Design of Pavements
Lecture Notes - Dr. Omar Osman
PCA Method –Thickness Design Example
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