Formula Used:
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The Width of Footing calculation determines the required width of a foundation footing based on soil properties and loading conditions, specifically for local shear failure scenarios using the net ultimate bearing capacity approach.
The calculator uses the formula:
Where:
Explanation: This formula calculates the minimum width required for a footing to prevent local shear failure in soil, considering soil cohesion, surcharge, and unit weight factors.
Details: Proper footing width calculation is essential for structural stability, preventing settlement, and ensuring the foundation can safely transfer loads to the soil without causing shear failure.
Tips: Enter all required soil parameters and loading conditions. Ensure values are in correct units (Pascal for pressure/stress, N/m³ for unit weight). All values must be positive and non-zero where applicable.
Q1: What is local shear failure?
A: Local shear failure occurs when the soil fails gradually with significant settlement before complete failure, typically in loose or compressible soils.
Q2: How does this differ from general shear failure?
A: General shear failure happens suddenly in dense soils with well-defined failure surfaces, while local shear failure occurs gradually in less dense soils.
Q3: What factors affect bearing capacity factors?
A: Bearing capacity factors depend on soil friction angle, with different values for general shear, local shear, and punching shear failure modes.
Q4: When is this calculation most applicable?
A: This calculation is particularly important for foundations on soils prone to local shear failure, such as loose sands or soft clays.
Q5: How does effective surcharge affect footing width?
A: Higher effective surcharge increases soil confinement, which generally increases bearing capacity and may allow for narrower footings.