Pad Footing Bearing Pressure

Isolated pad footing

The bearing capacity of the pad footing is paramount in any structural design. The foundation’s stability on the underlying soil is crucial for the entire structure’s integrity. To assess this, we must analyze the pad footing’s response to applied axial loads and bending moments, carefully observing the resulting bearing pressure distribution

Basis of design

First, determine the force P and any moments M that the structure demands from the footing under normal conditions. Next, ensure your footing dimensions respect the allowable bearing pressure q_a with these rustic conditions in mind. Now things get heavier as we consider the factored loads: evaluate the new axial force P’ and moment M’. This will lead you to determine an optimal linear pressure distribution!

Live Visualisation

Footing Response Diagram

Awaiting valid inputs

Pressure diagram will render here Enter valid footing dimensions and loading to display the centroid, eccentricity, contact length, and pressure block.

e = M / P --

Result

Maximum Bearing Pressure

No result

q_max --

Results stay disabled until all required values are valid.

Case --

Contact length --

Pressure range --

Inputs

Input Actions

Axial load Service or factored vertical load delivered to the footing. kN Moment about major axis Applied overturning moment used to compare against M/P eccentricity. kN·m Footing width Transverse footing dimension that stays constant in the pressure check. m Footing length in bending direction Dimension parallel to bending and eccentricity. m

Secondary Properties

Derived Check Values

Expand to review derived values and case checks.

Derived eccentricity, e = M/P--

q_avg--

q_min--

Limiting eccentricity, e_k = D/6--

Moment ratio check, M/P--

3(D/2 − e)--

Pressure zone--

This follows the textbook sequence in the reference figures: first derive e = M/P, compare it with e_k = D/6, then switch from a full-contact trapezoid to a triangular pressure block when e > e_k.

Saved Results

Comparison Register

0 saved

Timestamp	P (kN)	M (kN·m)	B (m)	D (m)	e (m)	q_max (kPa)	Case
Save design iterations to build a project-side comparison history.