Design Criteria: Code, Combos & Deflection

Where Load Criteria holds the project's loads, Design Criteria holds the rules that govern how those loads are applied: the code basis, the ASD and LRFD load combinations, the deflection limits, and the structural-system narrative. Defining them once lets a new beam design start pre-seeded with the project's combinations and limits.

Governing code & project basis#

At the top of the Design Criteria page you set the project's code foundation:

• Governing building code — e.g. "2021 International Building Code".
• Risk category — I, II, III, or IV.
• Custom fields — add your own labeled code-basis fields (label + value) for anything else you cite.
• Project description — a rich-text description of the project.

Edits autosave; a "Saving… / Saved" badge confirms persistence.

Load combinations (ASD & LRFD)#

Design Criteria maintains two separate combination sets — one ASD, one LRFD — and you choose which one seeds a beam design. Toggle between them with the ASD / LRFD switch, then edit the active set in the combination table.

Each combination is a name plus a set of factors keyed by load category:

1.2D + 1.6L  →  { "Dead": 1.2, "Live": 1.6 }
0.6D + W     →  { "Dead": 0.6, "Wind": 1.0 }

The load categories (the columns of the combination matrix) are editable. The default set is Dead, Live, Lr, Snow, Wind, E; add or remove categories as needed. Removing a category strips its factor from every combination in both sets.

Deflection limits#

The deflection criteria table defines named limits as an L/n divisor — for example L/360 (divisor 360) or L/240 (divisor 240) — with an optional note. Each load combination can be associated with one deflection limit via a dropdown in the combination table (or "No check" to leave it unchecked).

These associations are stored by combination name, so they round-trip cleanly into a beam design: the beam's case name matches the combination name, and the chosen limit follows.

Structural system narrative#

Two rich-text sections — Gravity system and Lateral system — let you describe the load paths (roof, floor, walls, columns, foundation; diaphragms, shear walls). These narratives are edited here and carry into the project's documentation.

The design load summary#

The Design Criteria page also shows a read-only Dead/Live load summary pulled live from Load Criteria — there's an "Open Load Criteria" link to edit it. You can hide individual loads from this summary view without deleting them; hidden loads are remembered and can be restored.

How it influences calcs#

The combinations, load categories, and deflection limits you set here use the same shapes a beam design uses, so they auto-seed a new beam design with no conversion — you pick ASD or LRFD when starting the design. Combined with Load Criteria, Design Criteria lets a project's calcs all start from the same governing assumptions.