Flexible pavement design – key inputs Design of flexible pavements should account for which of the following influences?
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Awheel loads
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Bintensity of traffic
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Cclimate of the region
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Dsub-grade conditions
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Eall the above
Answer
Correct Answer: all the above
Explanation
Introduction / Context:Flexible pavements transfer wheel loads through layered granular and bituminous materials. Performance and thickness requirements depend on multiple interacting factors.
Given Data / Assumptions:
- General highway design scenario.
- Standard flexible pavement structure.
Concept / Approach:Load magnitudes and repetitions (axle loads, traffic spectrum), environmental effects (temperature and moisture), and subgrade strength all determine layer thicknesses and material specifications.
Step-by-Step Solution:Wheel loads set structural demand.Traffic intensity determines cumulative damage (e.g., million standard axles).Climate drives temperature-susceptibility and moisture weakening.Subgrade CBR or modulus governs foundational support.
Verification / Alternative check:Mechanistic-empirical design methods explicitly combine these inputs to predict strains and cumulative damage.
Why Other Options Are Wrong:Each single factor alone is incomplete; all are needed for robust design.
Common Pitfalls:Ignoring seasonal high-water tables; underestimating traffic growth; not calibrating material properties to local climate.
Final Answer:all the above