PEB Reaction Data Workflow: From Software Output to Engineering Review

Reaction data on a PEB job is not a single printout. It is a sequence: an issued MBS run, a table someone can review, a signature, a foundation handoff, a citation on the approval set, and an archive that still makes sense six months later. Offices that skip the sequence send a PDF into a group chat and then argue about which number was current when the piers were poured. The workflow in this article is the path those numbers should take.

Each step already has a detailed companion. Reading reactions is How to Read and Use MBS Column Reactions. Tabulation is How to Organize MBS Reaction Data into a Usable Table. The go/no-go gate is MBS Output Quality Checks Before Using Results in Design Workflows. Drawing citation is From MBS Output Files to PEB Approval Drawings. Here the pieces are put in order, with owners, so a PEB team can run the same path on every building.

Tools sit inside the sequence; they do not replace it. StruTools MBS Reactions belongs at the extract-and-tabulate step. The StruTools MBS Approval Package belongs after the table is signed, when sheets are being composed. If file chaos is the reason the sequence keeps breaking, fix folders first using How Engineering Teams Can Organize MBS Files and Project Outputs. Do not skip the human sign-off because a tool already filled the cells.

Start from an issued run, not from a live model

The workflow does not begin when someone highlights a cell in the post-processor. It begins when a run is frozen and filed.

The output package described in Understanding MBS Output Files for PEB Engineering is the input. If that package does not exist, stop. Extracting reactions from a model that is still being edited guarantees that foundations and CAD will diverge before the week is over.

Pass the quality gate before you tabulate

Tabulating a bad run only produces a neat bad table. The gate in the quality-check article is step two, not a retrospective.

• Completeness and diagnostics
• Geometry versus the plan this issue claims to support
• Load list versus the basis of design
• Support types and reaction coverage
• A short gravity sanity test

Tabulate, then review the table as a document

The table is the object that moves. Emails are not the object. Screenshots are not the object.

Build the table to the schema in the reaction-table article, by hand or with StruTools MBS Reactions. Then review it as if it were a calculation sheet: headers, units, mapping, missing supports, uplift visibility. The reviewer is allowed to send it back. They are not allowed to 'fix a couple of cells' without recording the change and the source.

Handoff to foundations without a second translation

Foundation engineers should receive the signed table, not a paraphrase. If they need service instead of factored values, that is a column or a companion table, not a verbal conversion.

• Send the signed file, not a screenshot.
• State service versus factored in the header they will actually read.
• Include the sign convention and axis note.
• Include the analysis issue letter so their calculations can cite it.
• If they mark comments, those comments come back to the PEB analyst; they do not become a private foundation-only table.

Cite the same table on approval drawings

Approval sheets should not grow a third copy of the reactions with different rounding and dropped cases.

Either print a governed subset of the signed table on the anchor-bolt or design-data sheet, or point to the calculation package and print only the values the office standard requires on the drawing. In both cases the analysis issue letter appears on the sheet. CAD coordination details live in Coordinating MBS Results with CAD and PEB Approval Drawings.

Archive the chain, not the last email

Six months later, a change order will ask which reactions were current when the piers were released. The archive has to answer without a forensic search of inboxes.

• Issued MBS package
• Signed quality checklist
• Signed reaction table
• Foundation transmittal that cites the table issue
• Approval drawing issue that cites the same analysis letter

The PEB reaction sequence

Run these as named steps with dates, not as overlapping chats.

1. Freeze and file the MBS output package.
2. Complete the quality-check gate and sign it.
3. Extract and tabulate reactions into the office schema.
4. Review and sign the table.
5. Transmit the signed table to foundations with the analysis issue letter.
6. Cite the same issue on the approval set.
7. Archive package, table, transmittals, and drawing issue together.
8. If the building changes, start at step 1 with a new letter; do not patch the old table in place.

Engineering tips

• Give analysis issues letters or numbers that CAD can print. 'Latest' is not an issue.
• Keep one current table path per project. Copies for 'just the crane bay' become competing sources.
• If foundations work in a different unit system, convert once in the signed table, visibly.
• Record who is allowed to extract. Random access to the model is how unofficial tables start.
• When automation is added, insert it at tabulation, not at sign-off.

Common mistakes

Parallel tables for 'design' and 'drawings'

Two tables will diverge. One signed table, cited in two places, is the workflow.

Starting CAD while the gate is still open

Elevations drawn against a moving model will not match the table you sign next week. Freeze first.

Letting comments live only in chat

A foundation comment that never hits the table or the transmittal did not happen, as far as the archive is concerned.

Reaction workflow checklist for a PEB issue

Use at each drawing issue that claims to include reactions.

• Issued MBS package exists for this analysis letter.
• Quality checklist is signed for that package.
• Reaction table uses the office schema and cites the same letter.
• Table is signed.
• Foundations received the signed file, not a crop.
• Approval sheets cite the same analysis letter.
• No second unofficial table is in circulation.
• Archive folder contains package, checklist, table, and transmittal.
• A change to geometry or loads has a new letter, not a quiet edit.

Frequently asked questions

Who owns the reaction table on a PEB job?

The engineer responsible for the PEB frames owns the signed table. CAD may display it. Foundations may use it. Neither should become the unrecognized author of a replacement table.

How often should the workflow restart?

Whenever geometry, loads, supports, or design criteria change in a way that can move base forces. Cosmetic drawing edits do not require a new analysis letter; eave height does.

Can one table cover the whole building?

Yes, if grouping stays readable. Very large sites can split by frame line as long as issue letters stay consistent and coverage is complete.

Where does automation plug in?

At extract and tabulate, with StruTools MBS Reactions or a tested parser, still followed by human sign-off.

A workflow is how reactions stay true

PEB reaction data is only trustworthy when it travels as a signed object from an issued MBS run to foundations and drawings. The software does not manage that path. The team does.

If the path keeps breaking on lost files, continue with How Engineering Teams Can Organize MBS Files and Project Outputs. If it breaks on CAD mismatch, continue with Coordinating MBS Results with CAD and PEB Approval Drawings.