Understanding Beam Load Calculations
This calculator determines the maximum allowable load (point or UDL) for a simply supported beam based on deflection and stress constraints, supporting both imperial and metric units for structural design.
Load capacity depends on material properties (modulus of elasticity, yield strength), beam geometry (moment of inertia, section modulus), and constraints (deflection limit, safety factor). Default deflection limit is L/360, typical for floors.
Example Beam Load Calculation Results
| Parameter | Imperial | Metric | Scenario |
|---|---|---|---|
| Max Load (Point) | 1200 lb | 5338 N | Steel, 4x8 in. section, L/360 deflection |
| Max Load (UDL) | 150 lb/ft | 2189 N/m | 10 ft (3.048 m) beam |
| Controlling Constraint | Deflection | Deflection | L/360 limit |
| Moment of Inertia | 170.67 in⁴ | 7.1e7 mm⁴ | Rectangular section |
| Section Modulus | 85.33 in³ | 1.4e6 mm³ | Rectangular section |
How to Use the Beam Load Calculator
- Select the unit system (imperial or metric).
- Enter beam length and material (steel, wood, or custom modulus and yield strength).
- Choose section type (rectangular or I-beam) and enter dimensions.
- Select load type (point or UDL) and enter load position (for point load) and constraints (deflection limit, safety factor).
- Click "Calculate Maximum Allowable Load" to view the maximum load, controlling constraint, moment of inertia, and section modulus.
Beam Deflection Curve Under Max Load
Deflection along beam length for the calculated maximum allowable load.
Frequently Asked Questions
What is a deflection limit?
A deflection limit (e.g., L/360) is the maximum allowable beam deflection, often set by building codes to ensure structural comfort and safety.
How is the maximum load calculated?
The maximum load is the minimum of the load based on deflection (e.g., δ = 5 w L⁴ / (384 E I) for UDL) and stress (M = σ S / safety factor), ensuring neither constraint is exceeded.