Uniform pressure on soil given maximum moment is a footing design relationship used to determine the assumed uniform soil bearing pressure beneath a symmetrically loaded wall or strip footing when the maximum bending moment in the footing is known. The physical basis is that the soil exerts an upward distributed reaction beneath the footing while the wall load acts downward.
Uniform Pressure on Soil Given Maximum Moment Formula |
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\( P \;=\; \dfrac{ 8 \cdot M_{max} }{ \left( b - t \right)^2 } \) (Uniform Pressure on Soil) \( M_{max} \;=\; \dfrac{ P \cdot \left( b - t \right)^2 }{ 8 } \) \( b \;=\; t \pm \sqrt{ \dfrac{ 8 \cdot M_{max} }{ P } } \) \( t \;=\; b \pm \sqrt{ \dfrac{ 8 \cdot M_{max} }{ P } } \) |
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| Symbol | English | Metric |
| \( P \) = Uniform Pressure on Soil | \(lbf\) | \(N\) |
| \( M_{max} \) = Maximum Movement | \(lbf\;/\;sec\) | \(kg-m\;/\;s\) |
| \( b \) = Footing Width (the Dimension Along the Length of the Wall Itself) | \(ft\) | \(m\) |
| \( t \) = Wall Thickness | \(in\) | \(mm\) |
