PEB Design Coordination Between Analysis, Detailing and Fabrication

PEB projects have a structural problem that is not a member size. Analysis lives in one file, approval drawings in another, detailing in a third, and the shop in a nested plate. Each environment can be internally correct and still describe a different eave height. Coordination is the work of forcing those environments to share one building at a stated revision.

This is not a meeting culture article. It is about freeze points, mark control, comment ownership and the artefacts that prove two teams are looking at the same steel. The design workflow is the sequence. The approval process is the consultant-facing gate. Coordination is what happens at every handoff so those documents do not lie about each other.

Software makes handoffs easier and also easier to fake. A converter can push STAAD geometry toward CAD; MBS Approval Package can assemble sheets. Neither notices that the fabricator is still working from Rev B while engineering issued Rev D. People and file control have to notice.

Why PEB work fails at the interfaces

Interior typical frames are usually fine. Failure gathers at docks, cranes, mezzanines, expansion joints and “small” architectural moves after steel is released. Those items sit on the boundary between disciplines, so each team assumes the other still owns the problem. Coordination is naming the boundary object and the person who cannot drop it.

A second failure mode is speed. PEB schedules are short, so detailing starts while approval is open. That can be managed with written hold areas. Unmanaged, it produces holes in unapproved girts and a shop that is angry at the next revision cloud.

Analysis-to-detailing handoff

Detailing needs more than a PDF elevation. It needs a member list, taper points, connection design intent, flange-brace rules and a list of what is not approved. If the detailer is forced to measure a PDF, they will create a third geometry. Prefer a controlled list plus drawings that share marks with the analysis model, as discussed in the software stack.

What detailing may not invent

Haunch length, web depth, base fixity, brace bays and crane bracket location. Those return to analysis. Clash-driven hole moves on a purlin may be local — until they move a flange brace.

Hold areas

Clouded comments become hold areas in the detailing model. Work around them, do not guess them. The approval log is the detailing constraint list.

Detailing-to-fabrication handoff

The shop needs a release, not a WIP model. Piece marks, operations, weld maps and bolt lists must come from the issued revision. Verbal “start the columns, we’ll catch the rafters” is how two tapers of the same mark appear on the yard. If CNC is driven by the model, the model’s issued state is the legal drawing.

Change after release

A revised purlin punch after nesting is a cost event. Engineering should know which marks were released before issuing a cloud that looks small on a PDF.

Site queries

RFI answers that change steel must become drawing revisions. An email to the erector is not a record the next inspector can find.

Mark control is coordination you can audit

If column C7 is RF3 in the model, C7 on the plan, and 7C on the shop, you cannot audit the job. Pick prefixes for frames, columns, purlins, girts, braces and keep them from first analysis extract through CNC. Reaction tables must use the same marks. This is tedious and it is the cheapest coordination tool you have.

• One mark, three views: model, drawing, shop.
• No reuse of a retired mark for a different piece on the same job.
• Special frames get their own series, not “typical plus a note.”
• Bolts and anchors have identities civil and steel both recognise.
• Revision of a mark is visible; do not silently rename to dodge a comment.
• A mark map is issued when software environments cannot share names natively.

Meetings, freeze points and what to write down

You do not need a daily stand-up to coordinate a warehouse. You do need freeze dates for envelope, cranes and openings, and a short written agenda when those dates move. Meetings without a decision log are social events. The decision log is the coordination artefact: what changed, which files will be updated, who informs civil.

Invite the people who can change the files, not only the people who can talk about them. If architecture is absent, you will coordinate fiction. If the fabricator is absent from a discussion that changes splices, you will approve unshippable rafters.

A coordination rhythm that fits PEB schedules

Light enough to keep, strict enough to catch drift.

1. Kickoff: name masters for geometry, sizes, drawings and reactions (see the software guide).
2. Envelope freeze meeting: openings, cranes, joints; publish the input register.
3. Analysis complete: issue member list and preliminary reactions labelled as such.
4. Internal drawing review: marks, sizes, bracing versus the model.
5. Approval issue and comment cycle with a single log.
6. Detailing release meeting: hold areas, released marks, shop questions.
7. Fabrication release: model or shop set frozen; CNC from that state only.
8. Change control: any post-release cloud is costed and re-issued, including reactions if bases move.

Engineering tips

• Store PDFs, models and reaction tables of the same revision in one folder named by that revision.
• When a comment might affect foundations, civil is on the distribution the same day.
• Do not let chat be the only place a hold area is mentioned.
• A one-page member list printed on A4 still beats a 200 MB model nobody opened.
• If two analysis tools are in play, assign one as issue master.
• Close comments by sheet number; “various as discussed” is not closed.

Coordination failures that look like detailing errors

Three unofficial “current” models

The engineer’s working file, the check STAAD model, and the detailer’s import. Without a master flag, the loudest person wins.

Starting CNC on a detailing model that still contains trial members

Leftover bays become steel. Purge and issue; do not “remember not to nest those.”

Architecture issues a new dock plan to the owner but not to steel

Coordination includes distribution lists. If steel is not on the architectural transmittal, the PEB package is already stale.

Fabricator applies a favourite typical that was never compared to this frame’s forces

That is a design change made in the shop. Typicals need an engineering match, not loyalty.

No owner for the reaction table after the first issue

Everyone thought someone else would update civil. Name the owner on the cover notes.

PEB coordination health checklist

Run at each external issue and at detailing release.

• Masters for geometry, size, drawings and reactions are written down.
• Input register matches the architectural revision named on the notes.
• Analysis file named on the drawings exists in the project archive.
• Marks are consistent across model, plans, elevations and reaction table.
• Comment log status is current.
• Hold areas in detailing match open comments.
• Civil has the reaction revision that matches this steel issue.
• Released shop marks are listed if fabrication has started.
• Superseded files are marked and not sitting on the desktop named FINAL.
• Site RFIs have been folded into the current revision or listed as open.
• Special systems (crane, mezzanine) have an owner in analysis and in detailing.
• The next freeze date is known.

Frequently asked questions

Who should own PEB mark numbers — engineering or the shop?

Engineering should own the identity of members that appear on approval and in reactions. The shop may add piece-split marks, but the mapping back to the engineering mark must remain. If the shop renames everything, coordination with civil and with comments collapses.

How do you coordinate if the fabricator uses Tekla and the designer uses AutoCAD?

Agree the issued 2D PDF as the contractual picture, and agree how the Tekla model is updated when that PDF revises. Import analysis geometry carefully; see model to CAD workflow. Do not let Tekla become a silent redesign tool.

Is a weekly coordination meeting required?

Only if the project is changing. A quiet, frozen warehouse may need only milestone reviews. A live industrial plant with moving equipment needs a shorter loop. Match the rhythm to the rate of change, and always keep the decision log.

What is the first sign that analysis and detailing have diverged?

Mismatched marks, a haunch length that cannot be found in the model, or a brace bay that exists on only one artefact. Spot-check those three at every issue; do not wait for a site clash.

One revision story, four environments

Analysis, approval drawings, detailing and fabrication will always be different tools. Coordination means they still tell one revision story: the same envelope, the same marks, the same bases, the same open comments. When that story splits, steel is fabricated from folklore.

Use this guide with the PEB design workflow and approval drawing process. Coordination checklists do not design members or assign legal responsibility. Those remain with the project’s engineers and the standards named in the design basis.