1. What is the AWC Span Calculator?

The American Wood Council (AWC) span calculator determines the maximum allowable span for wood beams based on material properties and loading conditions. It helps ensure structural integrity and safety in wood construction.

2. How Does the Calculator Work?

The calculator uses the AWC span formula:

Where:

• \( E \) — Modulus of elasticity (psi)
• \( I \) — Moment of inertia (inches⁴)
• \( w \) — Uniform load (pounds per foot)

Explanation: The equation calculates the maximum span length a wood beam can safely support based on its stiffness (EI) and the applied load.

3. Importance of Span Calculation

Details: Proper span calculation is essential for structural safety, preventing excessive deflection, and ensuring compliance with building codes.

4. Using the Calculator

Tips: Enter the modulus of elasticity (E) in psi, moment of inertia (I) in inches⁴, and uniform load (w) in pounds per foot. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Where can I find E values for different wood species?
A: The AWC provides tables of E values in the National Design Specification (NDS) for Wood Construction.

Q2: How do I calculate moment of inertia (I)?
A: For standard dimensional lumber, I values are published in tables. For custom sections, I = (width × depth³)/12 for rectangular sections.

Q3: Does this account for live loads and dead loads?
A: The uniform load (w) should include both dead and live loads. Consult local building codes for appropriate load combinations.

Q4: What safety factors are included?
A: The formula includes standard safety margins from the AWC design specifications.

Q5: Can this be used for floor joists and roof rafters?
A: Yes, but additional considerations like deflection limits and load duration factors may apply.