Foundation Load Distribution Ratio Calculator
Calculate the total load, stress, and stability for a strip foundation based on dead, live, and wind loads. Supports metric (kN/m, m) and imperial (kip/ft, ft) units.
Result
Detailed Steps
Load Proportions
Formula
Foundation Load Distribution Calculation
Total load per unit length is calculated as:
Foundation area is calculated as:
Foundation stress is calculated as:
Stability checks:
- Overturning: Stabilizing Moment > Destabilizing Moment
- Sliding: Frictional Resistance > Horizontal Force
- Bearing Capacity: Soil Pressure < Allowable Bearing Capacity
Notes:
- Metric units: kN/m for loads, m for dimensions, kPa for stress.
- Imperial units: kip/ft for loads, ft for dimensions, psf for stress.
- Concrete self-weight: 24 kN/m³ (metric) or 150 lb/ft³ (imperial).
- Friction coefficient: 0.4 (concrete on soil).
- Allowable bearing capacity: ~150 kPa (metric) or ~3132 psf (imperial).
How to Use the Foundation Load Distribution Ratio Calculator
- Select the unit system (Metric or Imperial).
- Enter the dead load, live load, and wind load in the chosen units.
- Enter the foundation length, width, and depth.
- Choose your preferred display mode (Standard, Step by Step, or Chart).
- Click the “Calculate” button.
- View the results, including total load, foundation area, stress, stability checks, and a pie chart of load proportions.
Frequently Asked Questions (FAQs)
How is foundation load calculated?
The total foundation load per unit length is the sum of dead load, live load, and wind load (e.g., 100 kN/m + 50 kN/m + 20 kN/m = 170 kN/m). Stress is calculated by dividing the total load by the contact area.
How is foundation size measured?
Foundation size is determined by its perimeter measurements converted to area (e.g., Length × Width = 10 m × 1 m = 10 m²). Depth is considered for self-weight and stability.
What are stability checks?
Stability checks ensure the foundation resists overturning (stabilizing vs. destabilizing moments), sliding (frictional resistance vs. horizontal force), and excessive soil pressure (stress vs. bearing capacity).
Why use metric and imperial units?
Metric units (kN/m, m, kPa) are standard in most countries, while imperial units (kip/ft, ft, psf) are used in the US, ensuring compatibility for global users.
What is a strip foundation?
A strip foundation is a continuous footing that supports a linear structure like a wall, distributing loads along its length. It’s common in residential and low-rise buildings.