Mr Calcu | Estimate Safe Soil Bearing Capacity for Foundation Design

Estimate soil bearing capacity for foundations based on soil type, depth, and load conditions.

Soil Bearing Capacity Calculator Description

Understanding Soil Bearing Capacity

Soil bearing capacity refers to the ability of the ground to support loads from structures. It’s a crucial factor in foundation design. If underestimated, structures may settle or collapse; if overestimated, you may overspend on construction. The safe bearing capacity is derived by applying a factor of safety to the ultimate bearing capacity of the soil. Typical soil types include clay, sand, silt, and gravel, each offering varying capacities depending on moisture, density, and compaction.

General Values:

• Clay (Soft): 50–100 kN/m²
• Sand (Loose): 100–150 kN/m²
• Gravel: 300–500 kN/m²

These values are adjusted for depth and width of the footing, ground water table, and load characteristics.

Factors Affecting Soil Bearing Capacity

Several factors influence the soil’s load-bearing ability:

• Soil Type: Fine-grained vs. coarse-grained.
• Moisture Content: Water saturation reduces strength.
• Footing Shape: Square, rectangular, or circular pads distribute load differently.
• Depth of Foundation: Greater depth generally increases bearing capacity.
• Groundwater Table: Closer groundwater weakens soil structure.

Engineers typically follow Terzaghi or Meyerhof's methods to determine ultimate bearing capacity, then divide by a factor of safety (usually 2.5 to 3).

Calculation Approach

Our calculator allows you to input:

• Soil type (choose from predefined options)
• Width and depth of foundation
• Groundwater presence
• Factor of safety

It applies empirical equations to derive a realistic safe bearing capacity and adjusts for any groundwater effects. These results assist structural engineers, civil contractors, and homeowners in planning safer and more cost-efficient foundations. For detailed methods, refer to this Wikipedia article.