Does AWS D1.1 require pre-production weld mockups?

AWS D1.1:2025 does not mandate mockups as a general requirement. They are almost always owner- or engineer-specified supplementary requirements, though AWS D1.8 does require mockup testing for certain demand-critical seismic connections.

Can a weld mockup replace a PQR?

No. A mockup validates that a qualified WPS produces acceptable results at a specific joint geometry; it does not qualify the procedure. The PQR qualification must precede the mockup.

What NDE is typically applied to weld mockups?

Mockups usually receive the same NDE as production welds — MT or PT for surface discontinuities, UT for full-penetration groove welds. Some seismic and heavy-industrial specs require destructive cross-sections as well.

Who witnesses a weld mockup?

Typically the CWI of record and, on owner-specified mockups, the Engineer of Record or their designated special inspector. For AISC-certified shops, the QC Manager is always involved.

Sep 22, 20266 min read

Pre-Production Weld Mockups for Complex Structural Joints

Learn when owner specs and AWS D1.8 require pre-production weld mockup testing, what they prove beyond the PQR, and how CWIs document the results.

WPS PQR CWI AWS D1.1 Quality Control Structural Welding

New to procedures? Start with WPS welding: what a welding procedure specification is, with a filled-in example.

A PQR test plate tells you whether the welding parameters produce sound weld metal under controlled laboratory conditions. It does not tell you whether your welder can achieve that same quality at the actual joint geometry — inside a tight beam-column connection, on a heavily restrained box column splice, or at the awkward overhead position dictated by erection sequence. Pre-production weld mockup testing fills that gap.

Understanding when mockups are required, what they prove, and how to document the results is an increasingly important skill for CWIs and QC managers working on complex structural projects.

PQR vs. Mockup: What Each Proves

The PQR qualification process under AWS D1.1:2025 tests a WPS on a standardized test coupon at specified positions and thicknesses. Mechanical testing (tensile, bend, sometimes CVN impact tests governed by Table 6.8) verifies the weld metal and heat-affected zone meet minimum properties. This process is rigorous and code-required — but it deliberately uses simplified geometry to isolate the procedure variables.

A pre-production mockup is different in purpose:

It replicates actual joint geometry, including connection depth, access restrictions, backing conditions, and fit-up tolerances representative of production.
It validates welder technique for the specific joint configuration, not just for the test position.
It confirms NDE accessibility — particularly important for box columns and moment connections where UT scanner placement is constrained.
It verifies distortion control — that the planned weld sequence stays within dimensional tolerances for the actual structure.

The mockup assumes the WPS is already qualified. Its job is to prove the procedure works at the joint, not to qualify the procedure itself.

When Mockups Are Required

AWS D1.1:2025 does not contain a blanket mockup requirement. In most structural fab work, mockups are owner-specified additions to the project's welding requirements. However, several situations make them nearly standard practice:

Seismic demand-critical connections: AWS D1.8 — the seismic supplement to D1.1 — requires pre-qualification testing of certain demand-critical welded moment connections (beam flange-to-column flange CJP groove welds, in particular). These tests involve full-scale or reduced-scale mockups demonstrating both weld quality and connection ductility. If the contract references D1.8, verify whether the affected connections are classified as demand-critical.

Owner supplementary requirements for special inspection: Projects requiring special inspection under IBC Chapter 17 frequently include engineer-specified weld mockup provisions for CJP moment connections in seismic design categories D and above. Review the project specification's Division 05 welding section for explicit mockup language.

Heavy industrial and crane runway structures: AISC Design Guide 7 projects and similar heavy-lift structures often carry engineer-of-record requirements for mockup testing on crane girder splices and end plate connections due to fatigue and restraint concerns.

Fabricators qualifying new processes on critical work: Even when no specification requires it, a prudent QC program may call for an internal mockup before first production when introducing a new process or welder to a joint type not previously welded in that shop.

Joint Types That Most Commonly Trigger Mockup Requirements

The following configurations account for the majority of mockup requirements on structural steel projects:

Welded unreinforced flange (WUF-W) and welded flange plate (WFP) moment connections: Beam flange to column flange CJP groove welds under AISC 358 prequalified moment connections involve tight access, heavy thickness, and backing bar alignment that look very different from a flat-plate PQR coupon.

Box column corner welds and panel zone completions: Once three sides of a fabricated box column are assembled, the fourth-side CJP groove weld is made in highly restrained conditions. Access for UT scanning and for removing backing bars differs substantially from standard test positions. See box column CJP weld sequence considerations for more on sequence issues.

Column-to-base plate weld with full perimeter CJP or PJP requirements: Overhead and vertical-up positions on large section column bases can be awkward. A mockup confirms the welder can maintain parameter compliance throughout the full joint perimeter.

Transfer plate welds at floor transitions: Heavy transfer plates with multiple weld lines in close proximity create thermal interaction effects not present in isolated test coupons.

What to Document During a Weld Mockup

Documentation of the mockup is as important as the mockup itself. At minimum, capture:

Pre-weld records:

Actual joint dimensions and fit-up measurements (root opening, root face, included angle, misalignment)
Base metal heat numbers and certified mill test report references
Filler metal lot numbers and hydrogen designator certs
Preheat temperature measurements — method, location, and readings at the intervals specified in the WPS
Welder ID stamps and current WPQ certifications

In-process records:

Pass-by-pass voltage, amperage, and wire feed speed logs (or weld parameter monitor printouts)
Interpass temperature readings
Any NDE performed on root or intermediate passes (MT after back-gouge if applicable)
Photos of fit-up, root pass, and completed joint

Post-weld records:

Final dimensional measurements (including any distortion against nominal)
NDE report: MT or PT surface inspection, UT volumetric inspection for all CJP welds
Visual acceptance per D1.1:2025 criteria
CWI review signature and findings summary

If the owner specification requires destructive cross-sections, the mockup assembly is sectioned and macroetched; photos of the macrograph are retained with the mockup package. See CWI inspection documentation requirements for record format guidance.

Relationship to the WPS

A mockup does not generate new essential variable data the way a PQR does. It should not be used to expand the WPS's qualified range. What it does is produce a documented trail that the existing WPS, applied to the actual joint geometry by a qualified welder, met all acceptance criteria.

The mockup package should reference the applicable WPS and PQR by number, explicitly confirming that all welding was performed within the essential variable ranges of Table 6.6 (and Table 6.8 where CVN supplementary essential variables apply). Rule library based on AWS D1.1:2025; verify against your governing edition.

If the mockup fails NDE or dimensional checks, the cause investigation is the critical step — it may reveal a fit-up issue, a technique problem, or a gap between the PQR test conditions and production conditions. A failed mockup should not be concealed; it is exactly the kind of finding the program is designed to surface before real structural members are at risk.

Hold Points and Special Inspection Interface

On projects with special inspection under IBC Chapter 17, the mockup event is typically a contractual hold point — the special inspector must witness and accept the mockup before production welding of the affected connection type begins. Work this into the project schedule well in advance; special inspector scheduling conflicts have delayed structural steel erection on projects that didn't plan for mockup approval lead time.

Build the mockup hold point into your welding inspection and test plan (ITP) as a required witness event. For guidance on structuring hold points across your welding program, see structuring weld inspection hold points for CWIs.

Practical Takeaways for CWI and QC Managers

Review every new project specification for mockup requirements in Division 05 and Division 01 special inspection sections before the project kicks off. Determine early whether AWS D1.8 demand-critical provisions apply. Build the mockup schedule into the project Gantt, allowing time for NDE turnaround and special inspector availability.

If a project has no formal mockup requirement but involves joint configurations outside the shop's recent experience, consider running an internal mockup trial anyway. The cost of a few hours of welder time and NDE is substantially less than a production nonconformance on a moment frame column.

For shops looking to track WPS compliance, welder assignments, and inspection records across complex projects, wpswelding.com/pricing offers purpose-built tools for the CWI and QC manager who needs an audit-ready record without building it in a spreadsheet.

FAQ

Frequently asked.

Does AWS D1.1 require pre-production weld mockups?: AWS D1.1:2025 does not mandate mockups as a general requirement. They are almost always owner- or engineer-specified supplementary requirements, though AWS D1.8 does require mockup testing for certain demand-critical seismic connections.
Can a weld mockup replace a PQR?: No. A mockup validates that a qualified WPS produces acceptable results at a specific joint geometry; it does not qualify the procedure. The PQR qualification must precede the mockup.
What NDE is typically applied to weld mockups?: Mockups usually receive the same NDE as production welds — MT or PT for surface discontinuities, UT for full-penetration groove welds. Some seismic and heavy-industrial specs require destructive cross-sections as well.
Who witnesses a weld mockup?: Typically the CWI of record and, on owner-specified mockups, the Engineer of Record or their designated special inspector. For AISC-certified shops, the QC Manager is always involved.