The single-plate shear connection — universally called a shear tab — is one of the most common weld types in structural steel fabrication. A flat plate is shop-welded to a column or girder web; the beam web is then bolted to the plate in the field. Simple in concept, but the weld that connects the plate to the support carries the full shear load from the beam, and it must be qualified, executed, and inspected to the same standard as any structural weld.
Here is the WPS and CWI framework that governs shear tab welds under AWS D1.1:2025.
Connection Geometry and Load Path
A shear tab transfers beam shear to the supporting member through the fillet weld at the plate-to-support interface. The geometry has three primary configurations:
Column web shear tab. The plate is welded to the column web with fillet welds on both sides of the plate. Both welds are accessible from outside the column flanges — the easiest configuration to weld and inspect.
Girder web shear tab. The plate is welded to the girder web, again with fillet welds. Access conditions depend on where along the girder the connection falls and whether adjacent framing is already in place.
Extended shear tab (column face). The plate is welded to the face of the column flange. The weld is typically a single fillet on the plate edge against the flange. Access is straightforward, but the weld is a single-sided weld with no backup, which affects inspection.
The design fillet weld size — specified on the structural drawings — is calculated by the engineer of record based on the factored shear demand and the weld capacity using E70XX filler metal (F_w = 0.6 × F_EXX × 0.707 × effective throat). The WPS must match or exceed what the drawings call for.
WPS Selection
Prequalified Fillet Weld WPS
For standard structural steel — ASTM A36, A572 Grade 50, A992, A500 Grade B and C — the prequalified WPS path under AWS D1.1:2025 Clause 5 is the correct starting point.
The WPS must document:
- Base metal group(s): per AWS D1.1:2025 Table 6.9. A36 and A572 Gr 50 are in Group I; A992 wide flanges are also Group I. HSS columns in A500 Grade C are Group II. Confirm that your WPS covers the column material.
- Process and filler metal classification: SMAW with E7018, FCAW-G with E70T-1M, or GMAW with ER70S-3/ER70S-6 are the common prequalified choices for structural fillet welds. Confirm the filler is on the current prequalified list — A5.36 classifications were removed from GMAW/FCAW prequalified lists in the 2025 edition.
- Position: 1F (flat) for shop welds with the plate positioned horizontally; 2F (horizontal) for vertical plates welded in the horizontal position; 3F (vertical) if the column is already erected. The WPS must cover all positions in which production welds will be made.
- Fillet weld size range: document both the minimum and maximum size covered. The production weld size must fall within the qualified range.
- Preheat and interpass temperature: for A36 and A572 Gr 50, the prequalified minimum preheat when base metal is above 1/8 in thick and ambient temperature is above 32°F is typically 50°F. Heavier column sections (web thickness > 1.5 in) may require higher preheat per AWS D1.1:2025 requirements. See preheat verification methods for field and shop welding.
Tested WPS
If the column material is a non-prequalified grade (some ASTM A913 grades, A1085, or proprietary steel) or if the engineer specifies a process not covered by prequalified requirements, a tested WPS backed by a PQR is required. The PQR fillet weld test must include macro examination per AWS D1.1:2025 requirements. See how to qualify a welding procedure for the full PQR sequence.
Fillet Weld Sizing
Minimum Size: AWS D1.1:2025 Table 7.7
The code floor for fillet weld size is based on the thickness of the thicker part joined. For a shear tab welded to a column web:
| Thicker Part | Minimum Fillet |
|---|---|
| To 1/4 in | 1/8 in |
| Over 1/4 to 1/2 in | 3/16 in |
| Over 1/2 to 3/4 in | 1/4 in |
| Over 3/4 in | 5/16 in |
Rule library based on AWS D1.1:2025; verify against your governing edition.
In practice the design weld size almost always exceeds Table 7.7 minimums. A W14×82 column with a 0.510-in web paired with a 3/8-in shear tab will have a structural fillet size driven by shear demand, not the table minimum. Verify the actual drawing callout.
Maximum Size at Plate Edges
For the plate edge where the tab meets the column (the free edge of the plate is welded against the column surface):
- Plate ≥ 3/4 in: maximum fillet = plate thickness − 1/16 in
- Plate < 3/4 in: full plate thickness
A 3/8-in tab welded against a column flange has a maximum fillet of 3/8 in at the plate edge. If the design calls for a 1/2-in fillet, verify that the weld geometry is achievable — the plate may need to be thickened or a PJP groove weld used instead.
Access and One-Sided Weld Challenges
The most common inspection issue with shear tabs is the back-side weld. On a column web shear tab, fillet welds run on both sides of the plate. The first side — facing the erection aisle — is easily welded and inspected. The back-side weld is made between the plate and the column web in a confined space between the column flanges.
Challenges:
Electrode angle. A straight electrode cannot always reach perpendicular to the plate-web interface when the column flange restricts access. FCAW-G or GMAW with a short gun barrel angle is often better than SMAW in tight column flanges.
Weld length termination. The fillet weld should start and stop at the designed end distance from the top and bottom of the plate. Verify that the welder can reach the full length — partial welds in inaccessible locations show up in magnetic particle testing as length deficiencies.
Inspection access. The CWI needs to visually inspect the back-side fillet. If the column flange restricts direct sight, a mirror and a focused flashlight are required tools. The weld must be accessible for gauge measurement — not just visual.
For columns with narrow flanges or tight web-to-flange access, the WPS should specify the electrode diameter and gun extension. Document access restrictions in the traveler so the CWI knows to apply additional scrutiny.
CWI Inspection Protocol
Before Welding
- Shear tab plate material heat number verified against CMTR — the plate is a structural member, not hardware
- Plate dimensions and thickness match drawing callout
- Fit-up: plate plumb (vertical within tolerance), root opening within WPS limits (typically ≤ 1/16 in for prequalified fillet)
- Preheat measured per WPS requirement — use contact thermocouple or temperature-indicating crayon, measured 3 in from the weld joint on both the plate and the column web
- Welder ID and WPS number documented on the traveler
During Welding
- Filler metal classification matches WPS — check the spool or electrode label, not just the box
- Amperage and voltage verified by parameter log or welder's machine settings check
- No excess inter-pass slag — clean each pass before depositing the next
- Interpass temperature within WPS limit
After Welding
- Fillet leg size measured with weld gauge on both sides of the plate — document both measurements
- Weld length per drawing: confirm the weld begins and ends at the specified distances
- Visual acceptance: undercut ≤ 1/16 in at the toe, no surface cracks, no overlap that reduces effective throat
- For high-seismic or demand-critical applications, MT per AWS D1.8 provisions may be required — see magnetic particle testing documentation under AWS D1.1
For the complete production record-keeping framework, see production weld inspection daily reports and welder ID stamp and traceability requirements.
Common Deficiencies Found in Third-Party Audits
Undersized fillet weld. The most common finding. Travel speed too fast under production pressure. Apply fillet weld gauges to every shear tab — do not rely on visual estimation.
Short weld length. The welder terminates the weld before reaching the top or bottom of the plate, leaving unconnected plate length. This directly reduces the weld group capacity below the design assumption. Verify measured length against the drawing callout.
Wrong process for the position. SMAW E7018 can be sluggish in the vertical position (3F) without the correct technique. Using E6010 for vertical is occasionally seen — not a prequalified electrode under AWS D1.1:2025 for structural fillet welds without a tested WPS. Confirm electrode classification against the WPS for every production position.
No preheat on heavy column sections. A thick column web (over 1.5 in) in cold ambient conditions requires preheat. "It's not that cold" is not an inspection record — measure and document.
No back-side weld inspection. The accessible-side weld is routinely inspected; the column-web back-side weld is skipped. Both welds carry shear load. Both must be inspected and documented.
Managing WPS libraries, preheat lookups, and fillet gauge records across multiple projects is where paper-based QC systems break down. See wpswelding.com/pricing for a platform built around the CWI workflow.
Summary
Shear tab welds are structural welds — not assembly welds — and they need a WPS, qualified welders, and documented inspection:
- Design fillet size from drawings governs over Table 7.7 minimums; verify both
- Prequalified fillet WPS under Clause 5 is the standard path for structural steel
- Cover all production positions — shop welds at 1F/2F may differ from field erection at 3F
- Both sides of a column web shear tab must be welded and inspected
- Back-side weld access in tight column flanges is the most common inspection gap
Treating shear tabs as structural-grade work from WPS selection through final inspection keeps your QC records defensible and your connections performing as designed.