1. What is the Size Equation?

The Size Equation calculates the required height of a rectangular steel beam based on the applied moment, allowable stress, and beam width. It is derived from the flexure formula for rectangular sections.

2. How Does the Calculator Work?

The calculator uses the Size Equation:

Where:

• \( M \) — Applied moment (N·m)
• \( f \) — Allowable stress (N/m²)
• \( b \) — Beam width (m)
• \( \text{Size} \) — Required beam height (m)

Explanation: The equation ensures the beam can safely resist the applied bending moment without exceeding the material's allowable stress.

3. Importance of Size Calculation

Details: Proper beam sizing is crucial for structural safety, efficiency, and cost-effectiveness in construction and engineering projects.

4. Using the Calculator

Tips: Enter moment in N·m, stress in N/m², and width in meters. All values must be positive and non-zero.

5. Frequently Asked Questions (FAQ)

Q1: What units should I use for input?
A: Use consistent SI units: N·m for moment, N/m² for stress, and meters for dimensions.

Q2: Does this equation account for safety factors?
A: No, the allowable stress (f) should already incorporate appropriate safety factors as per design codes.

Q3: Can this be used for other materials besides steel?
A: Yes, the equation is valid for any homogeneous, isotropic material behaving elastically in bending.

Q4: What about other beam shapes?
A: This equation is specifically for rectangular cross-sections. Other shapes require different section modulus formulas.

Q5: How accurate is this calculation?
A: The calculation is theoretically exact for pure bending of prismatic rectangular beams within elastic limits.