Change orders from revised drawings, drafted against the steel you already detailed, bought and cut.

The engineer reissues six sheets with clouds and a new revision number, or answers an RFI with a sketch that moves a beam line. By then your detailer has drawings out for approval, the mill order is placed and the first sequence may be on the saw. Someone has to find every change, check it against the model, the cut list and the shipping log, and get a request to the GC before more work goes into steel that is about to change.

In the proof of concept, AI works through copies of revisions your team already handled and drafts the change list and the request your PM would have sent: what changed, piece by piece, where each affected piece stood that day, and the added or deleted work priced from the job's own estimate. Nothing goes to the GC.

Find every change, not only the clouded ones. Section 3.6 of the AISC Code of Standard Practice, ANSI/AISC 303-22, asks that revisions be clearly and individually indicated, dated and numbered, with each design drawing keeping its number for the life of the project; a revised model must identify its changed items or come with a written list. Its commentary treats a sketch as a new contract document with its own number and date. Real issues fall short: a cloud gets left off, or a size changes outside one. So the draft compares each reissued sheet with the one your detailer used and with the set the job was bought on, member by member, and lists anything found outside a cloud on its own line.

RFI answers and approval notes count too. Under Section 4.4.2, unless noted otherwise, changes shown in RFI responses or on approved approval documents are released for construction, and the fabricator must promptly tell the owner's designated representative for construction when one adds cost or delay. Drawings come back approved or approved subject to corrections noted, within 14 calendar days unless the contract says otherwise, and a correction written on a returned drawing can change the work with no new revision. So the draft reads your returned approval drawings and RFI log along with the reissued sheets. Section 4.6 also says RFIs are not for releasing the design a piece at a time.

Where the steel stood decides the cost. Section 9.3 has revisions confirmed by change order or extra work order, and Section 9.4.1 prices them on the work added or deleted, the change in its character, and the timing against material ordering, detailing, fabrication and erection. Its commentary asks the reviewer to allow for the disruption, the material already bought and the work already done. So each affected piece gets its status on the day the revision arrived: modeled, on an approval drawing, released, on order, cut, welded, coated or shipped. Tekla PowerFab, for one, matches model changes by GUID rather than piece mark and won't let an import change items already taken from stock; on a revision import it shows which assemblies have piece tracking or taken-from-stock entries, and each change can be allowed, saved for later or prevented.

Pound-priced jobs follow their own rules. On a price-per-pound contract, Section 9.2 sets pay weight as the gross weight on the fabrication documents, with no deduction for cuts, copes, clips, holes or weld preparation, and with weld metal and coatings left out. Section 9.4.3 says such contracts provide for changes made before release for construction, while changes after release adjust the price equitably. The draft weighs steel the way your contract defines it, prices from the job's estimate and your rate sheet, and leaves any line without a rate for your PM. Section 9.5.2 asks the fabricator to report a revision's effect on the schedule, so the draft carries your PM's schedule note or asks for one.

Your reviewer. The owner names the person who knows your change orders best, usually a project manager or the chief estimator. They hold each draft against the request your team sent: changes found and missed, each piece's status, weights and hours, rate sources, the schedule note and the questions for the GC. Include a revision that landed after steel was cut and one the GC pushed back on.

After a yes, each new issue, sketch or RFI answer on your open jobs gets a change list and a draft request as it arrives, for about 30 days.

Your PM checks every line, prices what has no rate and decides what goes to the GC. Nothing in your model, PowerFab or the shop schedule changes because of a draft, and the scoring table runs through the month.