Gravity analysis

SES offers two complementary ways to take gravity loads down to supports.

Tributary analysis

Each support (column, wall) is assigned the slab region nearest to it. Loads in that region are summed onto the support. This is fast, deterministic, and ideal for regular grids.

Steps:

1. Draw the slab, supports, and loads on the floor.
2. Run Tributary analysis.
3. Review per-support reactions in the results table and on the canvas.

FEM reactions

For more accuracy, SES meshes the slab and solves it as finite-element plates:

• DEAD/LIVE load cases are kept separate.
• Member self-weight is included automatically.
• Area, line, and point loads are integrated over their actual footprint (partial-area UDLs are handled as patches, not smeared slab-wide).
• A mesh-quality report flags slivers; an optional hard quality gate rejects poor meshes before solving.

Steps:

1. Draw the floor as above.
2. (Optional) Open FEM mesh settings to tune density and refinement.
3. Run FEM reactions.

Comparing the two

Use Analysis → Compare FEM vs Tributary to see per-support DEAD/LIVE side by side with the percentage difference. This is a quick sanity check: large divergences usually point to irregular geometry or stiffness effects worth a closer look.

Units & conventions

SES uses SI units (kN, m, kPa). Reactions are reported as downward gravity actions on each support. See Key concepts for definitions.