A large share of structural engineering is not new design. It is answering
whether an existing structure can take a change: a load rating, a renovation, a new rooftop
unit or solar array, a change of use. The starting point is almost always the same, and it is
the slow part: all the team has is the drawings.
To answer the question, an engineer rebuilds the structure from those drawings
by hand. They read the framing plan, list every member, work out each one's span, tributary
width, and the loads it carries, then run an AISC or SJI calculation on each. It is slow,
mechanical transcription, and it happens before any engineering judgment begins.
What if the rating happened on the drawing itself?
Read the framing plan, derive each member's inputs with receipts you can check, rate every
member with a deterministic code engine, and re-rate the whole plan the moment you add load.
What we built
Exactly that, scoped to one job we could verify end to end: load rating steel beams and
joists. A vision LLM reads the sheet, both the pixels and the prose, and a
deterministic AISC 360-16 and SJI engine does every calculation. The tool takes one
framing-plan page, vector or scanned, extracts each member, anchors a scale from the
written dimensions, derives spans and tributary widths, reads the load notes with quote
receipts, and rates every W-shape and joist. You correct inputs instead of transcribing
them, and an added-load slider re-rates the whole plan at once. The numbers below are
measured on the sheet the tool was developed on.
On the bundled Garrett College roof framing sheet, one run finishes
in under a minute: it reads all 187 member labels, rates 141 and refuses
the other 46 with a stated reason, and flags 78 members as
overstressed once a ballasted solar array (+8 psf) is added, up from 34.
VLMdoes only what
code cannot: it reads the pixels on scanned sheets, groups members into
equal-span banks, and reads the load criteria out of the prose notes. It never
computes a structural number.
codedoes the engineering:
a deterministic AISC and SJI engine rates every member, and every checkable claim the VLM
makes is verified against the sheet first. Anything unverified is tagged and left for
you to confirm.
full methodology →
Where this goes
This is an early build, scoped to steel beams and joists, but the structure generalizes.
It gets more useful with a firm's own data:
- The shape and joist tables are a verified core today; a firm's full section library
and connection types would widen what gets rated rather than refused.
- The same read, derive, verify loop extends to other members and other codes, with the
VLM still confined to reading and the math still in inspectable code.