Simple Wood Beam Design Calculator

Wood Beam Formulas:

\[ M = \frac{w \times L^2}{8} \] \[ f_b = \frac{6 \times M}{b \times d^2} \]

Uniform Load (w):

pli (pounds per linear inch)

Span Length (L):

inches

Beam Width (b):

inches

Beam Depth (d):

inches

Maximum Moment (M):

Bending Stress (f_b):

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1. What is Simple Wood Beam Design?

The Simple Wood Beam Design calculator helps determine the maximum moment and bending stress in a simply supported wood beam under uniform loading. These calculations are fundamental for structural design and safety assessments.

2. How Does the Calculator Work?

The calculator uses these fundamental beam formulas:

\[ M = \frac{w \times L^2}{8} \] \[ f_b = \frac{6 \times M}{b \times d^2} \]

Where:

\( M \) — Maximum moment (in-lb)
\( w \) — Uniform load (pounds per linear inch)
\( L \) — Span length (inches)
\( f_b \) — Bending stress (psi)
\( b \) — Beam width (inches)
\( d \) — Beam depth (inches)

Explanation: The first equation calculates the maximum bending moment at the center of the beam. The second equation determines the bending stress in the beam's extreme fibers.

3. Importance of Beam Calculations

Details: Proper beam design ensures structural integrity and prevents failure. The bending stress must be less than the allowable stress for the wood species and grade being used.

4. Using the Calculator

Tips: Enter all dimensions in inches and load in pounds per linear inch. For distributed loads (psf), convert to pli by multiplying by the tributary width.

5. Frequently Asked Questions (FAQ)

Q1: What is a simply supported beam?
A: A beam supported at both ends with free rotation (no moment resistance) at the supports.

Q2: How does beam depth affect strength?
A: Bending strength increases with the square of depth (doubling depth quadruples strength).

Q3: What is typical allowable bending stress?
A: Varies by species and grade - e.g., 900-1,800 psi for common framing lumber.

Q4: Does this account for beam self-weight?
A: No, you must add the beam weight to the uniform load if significant.

Q5: What about deflection limits?
A: This calculator doesn't check deflection, which often governs design (typically L/360 limit).