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Footing Size Formula:
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Footing size calculation determines the required area of a foundation footing based on the structural load and soil bearing capacity. Proper footing sizing is essential for ensuring structural stability and preventing settlement.
The calculator uses the footing size formula:
Where:
Explanation: The formula calculates the minimum area needed to distribute the structural load safely over the soil without exceeding its bearing capacity.
Details: Correct footing sizing is critical for structural integrity. Undersized footings can lead to excessive settlement or structural failure, while oversized footings result in unnecessary material costs.
Tips: Enter the total structural load in pounds and the soil bearing capacity in pounds per square foot. Both values must be positive numbers. The calculator will determine the required footing area in square feet.
Q1: What factors affect soil bearing capacity?
A: Soil type, moisture content, compaction, and depth of footing all influence soil bearing capacity. Professional soil testing is recommended for accurate values.
Q2: Should safety factors be applied to the calculation?
A: Yes, most building codes require applying safety factors to both load and soil capacity. Consult local building codes for specific requirements.
Q3: How is the total load calculated?
A: Total load includes dead loads (structure weight), live loads (occupancy loads), and environmental loads (snow, wind). A structural engineer should calculate precise loads.
Q4: Can this calculator be used for all foundation types?
A: This calculator provides a basic estimate for spread footings. Special foundations like piles or rafts require more complex calculations.
Q5: What units should be used for inputs?
A: This calculator uses pounds for load and pounds per square foot for soil capacity. Ensure consistent units for accurate results.