Shear stud welds buried under structural concrete are among the few weld types that become permanently inaccessible after a construction milestone. Once the concrete deck is placed, there is no way to visually check the weld collar, perform a bend test, or verify weld base geometry. For CWIs and fabricators working on composite steel frames, that reality makes the inspection window before the pour the single most important quality control event for stud welding.
AWS D1.1:2025 Clause 7 governs welded stud requirements—including procedure qualification, production controls, and inspection—for headed studs used as shear connectors in composite construction as well as other weld-on inserts and devices. Understanding what the code requires, and structuring the CWI hold points around those requirements, keeps composite beams in compliance and avoids costly after-pour disputes.
Why the Pre-Pour Window Is Non-Negotiable
Structural composite beams rely on the mechanical interlock between the steel beam and the concrete slab created by shear connectors. If a stud weld lacks fusion at the base, has a cracked collar, or was welded to a contaminated flange, the stud will not transfer horizontal shear forces at the design load. AISC 360 Chapter I design relies on the installed stud population being substantially complete and properly welded.
A CWI sign-off before the pour is not a paperwork formality. It is the last practical opportunity to remove defective studs, complete repairs, and confirm the weld base condition before the concrete permanently seals everything. Project schedules can pressure crews to minimize the gap between stud installation and concrete placement; the CWI's job is to hold that gap open long enough to do the inspection right.
AWS D1.1 Clause 7 Inspection Framework
AWS D1.1:2025 Clause 7 addresses production stud weld quality through a combination of visual inspection requirements and mechanical testing. The key elements that govern the pre-pour window are:
Visual acceptance criteria. Each production stud weld must have a full 360° weld collar (flash ring) with no cracks or lack of fusion visible at the base. The collar may be irregular in height around the circumference, but it must be continuous and bonded to the flange at the base perimeter. Ceramic ferrule fragments should be cleared away before inspection to expose the full collar.
Bend testing. AWS D1.1 requires that a sample of production stud welds be tested by bending. The CWI bends a stud 30° from its original axis—typically using a strike from a hammer and a pipe over the stud or a dedicated bending tool. The stud must not crack or fracture through the weld metal or heat-affected zone to pass. Bent studs that pass are left at the deflected angle; they remain structurally effective and are not straightened. Those that fail require corrective action before the pour.
Production sampling requirements. AWS D1.1 Clause 7 specifies how many studs per lot or area of work must be tested. The sampling provisions tie the testing frequency to the number of studs welded during a shift or on a given structural member. CWIs should review the specific sampling rate requirements in Clause 7 with their project WPS and inspection test plan (ITP) so the correct number of bends is performed. Arbitrarily testing only visually suspicious studs does not satisfy the code's sampling intent.
CWI Inspection Sequence: Area by Area
Structuring inspection as an area-by-area walkdown behind the stud welding crew is the most efficient approach on large composite frame projects. The following sequence works well in practice.
Step 1: Confirm WPS compliance before welding begins. The stud welding WPS establishes the qualified stud diameter, base metal condition, shielding gas (if used), power settings, and position. Before any production welding, verify that the crew is working from an approved WPS and that the welding equipment is calibrated or verified to match the qualified parameters. See Stud Welding WPS Under AWS D1.1 Clause 7 and Shear Stud Welding Qualification for WPS and qualification details.
Step 2: Flange surface condition before welding. Inspect the flange surface in the stud installation area for mill scale, primer, moisture, and paint. AWS D1.1 restricts welding through certain coatings and sets surface cleanliness requirements. Welding through heavy mill scale or over zinc-rich primer not covered by the WPS is a common deficiency on composite deck projects.
Step 3: Post-weld visual check. After welding, ceramic ferrules are removed and the collar is exposed. Walk the area and visually inspect each stud for a 360° collar, absence of base cracks, and absence of gross undercut at the flange-to-collar interface. Flag any stud with an incomplete collar, visible base crack, or stud that has separated for further evaluation.
Step 4: Ring test screening. Tapping each stud laterally with a hammer while listening for the acoustic response is a fast way to screen large populations of studs. A solid, well-fused stud returns a clear ring; a stud with a voids or hollow weld base returns a dull thud. This technique is not a code-mandated acceptance test, but it supplements visual inspection and helps prioritize which studs to examine more carefully or include in the bend test sample.
Step 5: Bend test the required sample. Identify and perform bend tests on the required sample per AWS D1.1 Clause 7 provisions. Record each test—stud location, stud number, test result. For large floor plates, mapping stud locations by bay and beam line helps the inspector and later reviewers find any repaired studs in the record package. See Shear Stud Deck Welding WPS Under AWS D1.1 for deck-integrated stud applications.
Step 6: Address failures before the hold point closes. Any stud failing visual or bend testing must be dispositioned before the pour. AWS D1.1 permits repair by applying a low-hydrogen fillet weld around the failed stud base, by installing a replacement stud adjacent to the removed or failed one, or by other Engineer-approved means. Document every repair action and re-inspect the repaired or replacement studs.