Winkler plate-bending FEM
Mat & Raft Foundation Calculator
AutoDesign’s foundation analysis tool models a concrete mat / raft (or spread footing) on Winkler soil springs using an in-browser plate-bending finite-element solver. It auto-meshes arbitrary mat shapes, refines near columns, and detects uplift (compression-only soil) automatically.
What this calculator does
- ✓Model mats, rafts and spread footings of arbitrary shape on elastic soil springs
- ✓Automatic meshing with refinement near column loads
- ✓Compression-only soil with automatic uplift detection
- ✓Reports soil bearing pressure, settlement and plate moments / shears
- ✓Bearing-vs-allowable check across the footprint
Frequently asked questions
How is the soil modeled? +
The soil is modeled as a bed of Winkler springs (modulus of subgrade reaction). The solver detects uplift and removes tension springs iteratively, so areas that lift off are not credited with bearing.
Can it handle non-rectangular mats? +
Yes. The mesher handles arbitrary polygon shapes (including L-shapes and circles) and refines the mesh near column loads for accuracy.
What outputs does the foundation calculator give? +
Soil bearing pressure distribution, settlement, plate moments and shears, and a bearing-vs-allowable check. Punching/one-way shear and flexural rebar design are planned follow-ups.
Ready to run a design?
Open the Mat & Raft Foundation Calculator in your browser — no install required.
Launch calculator