Link Loads into a Calc

Once a project's Load Criteria is defined, you can pull a load's psf into a specific calculation instead of transcribing the number. The link is live: ClearSpan records which criteria load the calc drew from, so a later change to the criteria psf is flagged on the calc.

Linking from Load Criteria#

When you build a load for a calc, you can either supply a psf yourself or pull one from the project's Load Criteria. Pulling from criteria does two things at once: it reads the psf for you, and it stamps a source trail back to the criteria load.

Each linked load records source_data = {project_id, load_id}, which is how the app marks the load as linked and flags it stale if the criteria psf later changes. The load's category is inherited from the criteria load (dead → Dead, live → Live, and so on), and you can override it — for example, to tag a roof "live" load as Lr — while keeping the link.

Linking via the Claude connector#

If you drive ClearSpan from the Claude Desktop connector, two tools pull loads straight from Load Criteria:

• define_area_load_from_criteria — derive a uniform line load. Pass the criteria_load_id and a tributary_width_ft; the psf is read from the criteria load.
• define_point_load_from_criteria — derive a point load P at position x_ft. Give the tributary area as a single area_sqft or as a named-dimension build-up.

Both accept an optional load_category to override the inherited category and an optional name, and both return a ready-to-use load object carrying the live load_criteria link.

define_area_load_from_criteria(
  project_id        = 42,
  criteria_load_id  = "seed-dead-roof",
  tributary_width_ft = 10
)

The returned load drops straight into a beam design's load pattern. For the conversion math behind these tools, see Area & Point Loads.

The criteria-free path#

You are never required to link to Load Criteria. The companion tools define_area_load and define_point_load take a psf from anywhere — a code table, a manufacturer cut sheet, a hand calc, or another member's reaction — and convert it the same way, citing the source with a source_label. Use those when the value doesn't live in the project criteria.

Keeping calcs in sync#

The point of linking is that the calc and the criteria stay aligned. If you update a psf in Load Criteria after linking it, the calc surfaces that its source value changed, so you can re-pull and re-run rather than letting a stale number ride. Once a load is in a calc, design and run it like any other — see Wood Beam Calcs.