1. What is the Roof Truss Span Formula?

The Roof Truss Span formula calculates the maximum span for roof truss based on load, length, modulus of elasticity, moment of inertia, and deflection. It provides a structural engineering calculation for determining appropriate truss spacing and sizing.

2. How Does the Calculator Work?

The calculator uses the Roof Truss Span formula:

Where:

• \( Load \) — Distributed load (lb/ft)
• \( Length \) — Length of the truss (ft)
• \( E \) — Modulus of elasticity (psi)
• \( I \) — Moment of inertia (in^4)
• \( Deflection \) — Maximum allowable deflection (in)

Explanation: The formula calculates the maximum span by considering the material properties and structural requirements to ensure safety and stability.

3. Importance of Span Calculation

Details: Accurate span calculation is crucial for structural integrity, ensuring roof trusses can support intended loads without excessive deflection or failure.

4. Using the Calculator

Tips: Enter load in lb/ft, length in ft, modulus of elasticity in psi, moment of inertia in in^4, and deflection in inches. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is modulus of elasticity (E)?
A: Modulus of elasticity is a material property that measures its stiffness or resistance to elastic deformation under load.

Q2: What is moment of inertia (I)?
A: Moment of inertia is a geometric property that measures how a cross-section resists bending.

Q3: What is typical deflection limit for roof trusses?
A: Typical deflection limits are L/240 for live loads and L/180 for total loads, where L is the span length.

Q4: Are there limitations to this formula?
A: This formula provides an approximation and should be verified by a structural engineer for specific applications and local building codes.

Q5: Can this calculator be used for floor trusses?
A: While similar principles apply, floor truss calculations may require different deflection limits and loading considerations.