Which book provides the required structural number (SN)?

• A. MEPDG
• B. AASHTO 1993
• C. Highway Manual
• D. Transportation Engineering Textbook

Answer: (B)

The correct answer is AASHTO 1993, as it is specifically designed for the design of flexible pavements and includes guidelines for calculating the structural number (SN). The structural number is essential for understanding the required thickness of asphalt layers needed to support projected traffic loads and environmental conditions.

The AASHTO 1993 design guide provides a detailed methodology for determining the structural number by considering factors such as subgrade strength, expected traffic, and performance criteria for the pavement. This makes it a crucial document for civil engineers engaged in transportation engineering, particularly in the design and analysis of pavement structures.

In contrast, while the MEPDG (AASHTO's Mechanistic-Empirical Pavement Design Guide) does involve structural design, it employs a different approach that integrates analytical models and performance prediction rather than providing a straightforward structural number calculation. The Highway Manual may cover various transportation topics, but it does not specifically focus on the structural number necessary for pavement design. The Transportation Engineering Textbook may provide foundational knowledge but is unlikely to contain the specific structural number calculations required for pavement design per AASHTO guidelines.