Single Plate Shear Connection (Shear Tab) — Design, Capacity & AISC Checks

The shear tab (also called a single plate shear connection or fin plate) is the most widely used simple connection in structural steel building construction. A rectangular plate is shop-welded to the supporting member -- typically a column flange or girder web -- and field-bolted to the beam web. It transfers vertical shear from the beam to the support and is designed as a pinned (simple) connection that permits beam-end rotation.

Shear tabs are favored because they are economical to fabricate, fast to erect (only field bolting required), and well-standardized through AISC Manual Part 10 tables. This reference covers the complete design procedure per AISC 360-22, capacity tables for common configurations, plate thickness selection, multi-code comparison, a worked example, and common design mistakes.

Quick access: Bolted connections calculator → | Welded connections calculator → | All reference tables →

Table of contents

• Anatomy of a shear tab
• Design procedure per AISC 360
• Bolt shear
• Plate bearing and tearout
• Plate gross shear yielding
• Plate net shear rupture
• Block shear on plate
• Weld strength
• Plate flexural yielding (ductility check)
• Capacity table
• Plate thickness selection guide
• Conventional vs. extended shear tabs
• Worked example
• Multi-code comparison
• Common mistakes
• Frequently asked questions
• Run this calculation
• Related references

Anatomy of a shear tab

A shear tab connection consists of four primary components:

• Plate: Typically 1/4" to 1/2" (6 mm to 13 mm) thick ASTM A36 steel, with a width of 3" to 4.5" (75 mm to 115 mm). The plate length depends on the number of bolts and the vertical bolt spacing.
• Weld: Fillet weld on both sides of the plate to the supporting member. This is a shop weld, applied under controlled conditions. Weld size is typically 5/16" to 1/2" (8 mm to 13 mm) depending on plate thickness.
• Bolts: A single vertical line of bolts through the beam web (field bolts). Standard practice uses 3/4" or 7/8" (M20 or M22) ASTM A325 bolts in bearing-type (N) condition.
• Standard configuration: 2 to 12 bolts at 3" (75 mm) vertical spacing, using standard holes. The most common configurations in building construction are 3-bolt through 6-bolt arrangements.

The plate is positioned with the bolt line a fixed distance from the weld line (typically 2.5" to 3" for conventional configurations). This offset creates an eccentricity that must be accounted for in the weld design.

Design procedure per AISC 360

The design of a single plate shear connection per AISC 360-22 and AISC Manual Part 10 involves the following limit state checks. Each must be evaluated independently and the lowest capacity governs.

Bolt shear

Each bolt in single shear must satisfy:

phi * Rn = 0.75 * Fnv * Ab

where Fnv is the nominal shear stress from AISC Table J3.2 and Ab is the nominal bolt area. For a 3/4" A325-N bolt with threads included in the shear plane: Fnv = 54 ksi, Ab = 0.4418 in^2, and phi_Rn = 17.9 kips (79.6 kN) per bolt.

The total bolt group shear capacity for n bolts in a conventional configuration (where eccentricity may be neglected per AISC Manual Part 10 criteria) is:

phi * Rn_total = n * phi * Rn_single

Plate bearing and tearout

Check each bolt hole for two limit states on both the plate and the beam web. The thinner element governs.

Bearing strength (deformation at service load considered):

phi * Rn = 0.75 * 1.2 * Lc * t * Fu  (per bolt)
Upper limit: phi * Rn = 0.75 * 2.4 * d * t * Fu

Tearout strength governs when the clear distance Lc (from bolt hole edge to plate edge) is small. End bolts in the line have the shortest edge distance and lowest tearout capacity.

For standard holes: Lc = edge distance - (hole diameter)/2. Hole diameter for a 3/4" bolt in a standard hole = 13/16" (21 mm).

Plate gross shear yielding

The plate must resist shear yielding across its full gross section:

phi * Rn = 1.00 * 0.60 * Fy * Ag_plate = 1.00 * 0.60 * Fy * tp * Lp

where tp = plate thickness and Lp = plate length (n bolts x 3" spacing + top and bottom edge distances). For A36 plate (Fy = 36 ksi), this becomes phi_Rn = 21.6 x tp x Lp.

Plate net shear rupture

The net section through the bolt holes must resist shear rupture:

phi * Rn = 0.75 * 0.60 * Fu * Anv = 0.75 * 0.60 * Fu * (Lp - n * dh) * tp

where dh is the bolt hole diameter (including the 1/16" allowance for standard holes) and n is the number of bolts. For A36 plate (Fu = 58 ksi) with 3/4" bolts in standard holes (dh = 13/16"): phi_Rn = 26.1 x (Lp - n x 0.8125) x tp.

Block shear on plate

Block shear rupture is a combined tearing-and-shear failure mode where a block of material tears out from the plate around the bolt group. Per AISC Section J4.3:

phi * Rn = 0.75 * (0.60 * Fu * Anv + Ubs * Fu * Ant)

where Anv is the net area in shear (along the vertical line of holes), Ant is the net area in tension (across the top or bottom bolt row), and Ubs = 1.0 for uniform tension stress distribution (typical for shear tabs). Block shear often governs for 2-bolt and 3-bolt configurations where the tension area is small.

Weld strength

The fillet weld on both sides of the plate must resist the beam reaction plus the eccentric moment from the offset between the bolt line and the weld line. For E70XX electrodes:

phi * Rn = 2 * 0.75 * 0.60 * 70 * 0.707 * w * Lw = 44.7 * w * Lw

where w = weld leg size (inches) and Lw = weld length (inches), which equals the plate length. For the eccentricity effect, the weld is checked using the instantaneous center of rotation method or the AISC Manual tables for eccentrically loaded weld groups.

A common rule of thumb: the weld size should be at least 5/8 x tp to develop the plate in shear.

Plate flexural yielding (ductility check)

The beam reaction acts at the bolt line, creating a moment about the weld line. The eccentricity e is the horizontal distance from the bolt line to the weld. The plate must have sufficient flexural ductility to accommodate the beam-end rotation without fracturing.

Conventional configuration (AISC Manual Part 10): When the plate satisfies the AISC Manual Part 10 criteria -- plate thickness tp less than or equal to a based on the bolt diameter (a = bolt diameter for standard holes), n less than or equal to 12 bolts, standard holes, and 3" bolt spacing -- the eccentricity may be neglected for the bolt group check and is instead applied to the weld check.

Extended configuration: The plate extends significantly beyond the support face (for example, when framing to a column web and the plate must clear the column flanges). Extended shear tabs require explicit eccentricity analysis for both the bolt group and the weld group using the instantaneous center of rotation method.

A key ductility requirement per AISC is that the plate thickness should not exceed the beam web thickness plus 1/16". This ensures that inelastic rotation occurs in the plate rather than causing a brittle fracture through the beam web bolt holes.

Capacity table -- AISC Table 10-9a

Approximate available shear strength (phi_Rn) for conventional single-plate shear connections with 3/4" A325-N bolts at 3" spacing, A36 plate (Fy = 36 ksi, Fu = 58 ksi), standard holes, and 1.25" edge distances. Values are in kips (kN in parentheses). All values assume the plate satisfies AISC Manual Part 10 conventional configuration limits.

Values are approximate and depend on specific geometry including edge distances, bolt spacing, and beam web thickness. Always verify with the actual AISC Manual Table 10-9a for your exact configuration. The governing limit state may shift between bolt shear, plate bearing, block shear, or gross shear depending on the geometry.

Plate thickness selection guide

Selecting the right plate thickness is critical for both strength and ductility. The plate must be thick enough to develop the required capacity but thin enough to ensure ductile behavior.

Relationship to beam web thickness

The fundamental rule: the shear tab plate should be the weaker (thinner) element in the bolted joint. This ensures that inelastic rotation occurs through plate yielding rather than tearing through the beam web, which would be a sudden, brittle failure.

tp <= tw_beam + 1/16"

where tp = plate thickness and tw_beam = beam web thickness. This limit is essential for connections that must accommodate beam-end rotation, particularly in gravity framing.

Recommended plate thickness by beam size

Weld sizing relative to plate thickness

The fillet weld size should develop the full shear capacity of the plate. A conservative guideline:

w >= 5/8 * tp  (minimum weld leg size)

Weld size must also meet the AISC Table J2.4 minimum fillet weld size requirements based on the thinner part joined.

Conventional vs. extended shear tabs

Conventional shear tab

The plate is attached directly to a column flange or beam web with the bolt line close to the support face. The distance from the weld to the bolt line is approximately equal to the bolt gage (typically 2.5" to 3"). In this configuration, the eccentricity effect is relatively small and the AISC Manual Part 10 tables (Table 10-9a through 10-9e) may be used directly. The bolt group eccentricity is neglected (all bolts assumed to share shear equally) and the eccentric moment is applied to the weld.

Extended shear tab

The plate extends significantly beyond the support face. This is required when a beam frames into a column web and the plate must project past the column flanges, or when the beam is offset from the support. Extended shear tabs require:

• Explicit eccentricity analysis for the bolt group using the instantaneous center of rotation method (AISC Tables 7-7 through 7-14)
• Weld group analysis for the combined shear and moment
• Plate flexural yielding check with the full eccentricity
• Careful attention to plate stability and potential lateral-torsional buckling of the extended portion

Extended configurations have lower capacity per bolt than conventional configurations because the eccentric moment increases bolt forces.

Worked example -- W21x62 beam to W14x82 column

Design a conventional single-plate shear connection for the following:

Given:

• Beam: W21x62 (d = 20.99 in., tw = 0.400 in., Fy = 50 ksi, Fu = 65 ksi)
• Column: W14x82 (d = 14.3 in., bf = 14.7 in., tf = 0.855 in.)
• Factored beam reaction: Ru = 75 kips (334 kN)
• Bolts: 3/4" A325-N, standard holes, single vertical line, 3" spacing
• Plate: ASTM A36 (Fy = 36 ksi, Fu = 58 ksi)
• Weld: E70XX fillet weld, both sides
• Configuration: 4-bolt conventional

Step 1 -- Bolt shear:

phi * Rn_per bolt = 0.75 * 54 * 0.4418 = 17.9 kips
phi * Rn_total = 4 * 17.9 = 71.4 kips

71.4 kips < 75 kips -- not adequate. Increase to 5 bolts.

phi * Rn_total = 5 * 17.9 = 89.3 kips > 75 kips  OK

Step 2 -- Plate thickness selection:

tw_beam = 0.400". Maximum plate thickness = 0.400 + 1/16" = 0.4625". Select tp = 3/8" (0.375").

Step 3 -- Plate geometry:

Plate length Lp = (5-1) x 3" + 2 x 1.25" = 14.5". Plate width bp = 4" (typical).

Step 4 -- Plate gross shear yielding:

phi * Rn = 1.00 * 0.60 * 36 * 0.375 * 14.5 = 117.5 kips > 75 kips  OK

Step 5 -- Plate net shear rupture:

Hole diameter dh = 13/16" = 0.8125". Net length = 14.5 - 5 x 0.8125 = 10.44".

phi * Rn = 0.75 * 0.60 * 58 * 10.44 * 0.375 = 102.2 kips > 75 kips  OK

Step 6 -- Block shear on plate:

Anv (net shear area along bolt line) = (14.5 - 1.25 - 4.5 x 0.8125) x 0.375 = (14.5 - 1.25 - 3.656) x 0.375 = 3.598 in^2.

Ant (net tension area at bottom bolt) = (4/2 - 0.8125/2) x 0.375 = (2.0 - 0.406) x 0.375 = 0.598 in^2.

phi * Rn = 0.75 * (0.60 * 58 * 3.598 + 1.0 * 58 * 0.598)
        = 0.75 * (125.2 + 34.7)
        = 0.75 * 159.9
        = 119.9 kips > 75 kips  OK

Step 7 -- Bolt bearing on plate:

Assume edge distance Le = 1.25" (bottom bolt), spacing s = 3" (inner bolts).

Bottom bolt: Lc = 1.25 - 0.8125/2 = 0.844". phi_Rn = 0.75 x 1.2 x 0.844 x 0.375 x 58 = 16.5 kips.

Inner bolts: Lc = 3.0 - 0.8125 = 2.188". phi_Rn = min(0.75 x 1.2 x 2.188 x 0.375 x 58, 0.75 x 2.4 x 0.75 x 0.375 x 58) = min(42.8, 29.4) = 29.4 kips per bolt.

Total bearing: 16.5 + 4 x 29.4 = 134.1 kips > 75 kips OK.

Step 8 -- Weld design:

Eccentricity e = 3" (bolt line to weld line). Plate length = 14.5".

Weld group: two vertical lines, each 14.5" long, loaded with Vu = 75 kips at e = 3".

Using AISC Manual Table 8-4 (eccentrically loaded weld groups, in-plane):

C = 3.48 (approximately, for a = e/Lw = 3.0/14.5 = 0.207, 2 vertical lines).

Required weld capacity per inch: Ru / C = 75 / 3.48 = 21.6 kips/in. per weld line.

Required weld size: w = 21.6 / (0.75 x 0.60 x 70 x 0.707 x 2) = 21.6 / 44.7 = 0.483".

Use 1/2" fillet weld both sides (meets minimum per AISC Table J2.4 for 0.855" column flange).

Check 5/8 x tp rule: 5/8 x 0.375 = 0.234". Provided weld = 1/2" > 0.234" OK.

Summary: 5-bolt single plate, 3/8" A36 plate, 4" wide x 14.5" long, 1/2" E70XX fillet weld both sides to W14x82 column flange. Capacity = 89.3 kips (governed by bolt shear).

Multi-code comparison

Shear tab (fin plate / single plate) connections are used globally under different design standards. The design philosophy is similar -- a plate welded to the support and bolted to the beam -- but the specific limit states and resistance factors differ.

AISC 360-22 vs. other codes

AS 4100 single plate connections

The Australian standard AS 4100:2020 does not have the same prescriptive tables as AISC Manual Part 10. Single plate connections are designed from first principles using the bolt, plate, and weld provisions in Chapters 9 and 10. Key differences:

• Eccentricity must always be included for bolt group design (no AISC-style conventional assumption)
• Bolt capacity reduction for connections with more than one bolt in the line of force uses the length reduction factor per AS 4100 Clause 9.3.2.1
• Weld design uses the plastic method for eccentrically loaded weld groups per AS 4100 Clause 9.5.2

EN 1993-1-8 fin plate design

The Eurocode approach to fin plate (single plate) connections is detailed in the SCI publication "Green Book" (P358) for simple connections. The key checks include:

• Supported beam web: Shear and bearing at bolt holes, block tearing, and notched beam checks
• Fin plate: Shear, bending, and bearing at bolt holes, with an interaction check for combined shear and bending
• Weld: Full-strength weld to the supporting member is recommended (develops plate capacity)
• Rotation capacity: The plate thickness is limited relative to the beam web thickness to ensure adequate rotation capacity, similar to the AISC ductility rule. A maximum plate thickness of 0.50 x beam web thickness is sometimes used for thin webs

Common mistakes

1. Not checking the beam web for bearing and tearout. The beam web is often thinner than the shear tab plate and may govern the connection capacity. If the web tears out, the failure is sudden and non-ductile. Always check both the plate and beam web for each bolt.

2. Ignoring eccentricity for extended shear tabs. Extended configurations that project beyond the support face require explicit bolt group eccentricity analysis. Using the AISC Manual Part 10 conventional tables for an extended configuration overestimates capacity.

3. Plate too thick relative to beam web. If the plate is significantly thicker than the beam web, failure shifts from ductile plate yielding to brittle beam web tear-out. Keep tp less than or equal to tw_beam + 1/16" to maintain the intended failure hierarchy.

4. Undersized weld relative to plate capacity. The weld must resist both the direct shear and the eccentric moment from the bolt line offset. A weld that only satisfies the minimum size requirement from AISC Table J2.4 may be insufficient. Use the 5/8 x tp rule as a starting point and verify with the eccentric weld group calculation.

5. Not checking block shear on the plate. Block shear rupture is a combined tension-and-shear failure that can govern, especially for 2-bolt or 3-bolt configurations with small edge distances. It is independent of bolt shear capacity and must be checked separately.

6. Omitting the coped beam check. When the beam is coped (top or bottom flange cut to clear the supporting member), the reduced cross-section must be checked for flexural yielding, shear yielding, and local buckling at the cope. The cope creates a stress concentration that can significantly reduce the beam's effective capacity at the connection.

7. Using oversized or slotted holes without slip-critical design. If oversized or slotted holes are used in the plate (for erection tolerance), the connection must be designed as slip-critical if the holes are in the direction of the load, per AISC Section J3.8. Standard bearing-type design is not applicable.

8. Neglecting erection stability requirements. OSHA requires that connections provide sufficient stability during erection. A minimum of two bolts must be installed before the crane releases the beam. Single-bolt connections are prohibited for erection stability. Verify that the two-bolt erection configuration has adequate capacity for construction loads.

Frequently asked questions

What is a shear tab connection? A shear tab (also called a single plate shear connection or fin plate) consists of a rectangular steel plate shop-welded to the supporting member and field-bolted to the beam web. It transfers vertical shear only and is designed as a pinned connection that allows beam-end rotation. It is the most common simple connection type in North American steel construction.

How many bolts does a shear tab need? The number of bolts depends on the magnitude of the beam reaction. Typical configurations range from 2 bolts (light beams with reactions under 30 kips) to 7 or 8 bolts (heavy beams with reactions over 150 kips). The most common configurations are 3-bolt (W16-W18 beams), 4-bolt (W18-W21 beams), and 5-bolt (W21-W24 beams). A minimum of 2 bolts is required for erection stability per OSHA.

Can a shear tab transfer moment? No, by design intent. Shear tabs are classified as simple (pin) connections that transfer vertical shear only. While some incidental moment develops due to the stiffness of the plate and bolts, the connection is not designed for it and the beam is analyzed as simply supported. For moment transfer, use moment connections such as end plates, flange plates, or direct flange welding.

What is the difference between a shear tab and a double-angle connection? Both are simple shear connections. A double-angle connection uses two angles bolted (or welded) to the beam web and bolted to the support, with angles on both sides of the web. A shear tab uses a single plate on one side of the web. Shear tabs are more economical (less fabrication and fewer parts) but provide slightly less rotational flexibility. Double-angle connections are preferred when the beam frames into a girder web because they provide a symmetrical load path.

How do I select the plate thickness for a shear tab? Start with the maximum thickness rule: tp should not exceed tw_beam + 1/16" to ensure ductile behavior. Then verify that the selected thickness provides adequate capacity for all limit states (gross shear yielding, net shear rupture, block shear, bearing). For most W-shapes, 3/8" plate works for W18-W21 beams, 5/16" for W14-W16, and 1/2" for W24 and larger. Refer to the plate thickness selection guide table above.

What weld size is required for a shear tab? The weld must resist the factored shear plus the eccentric moment. A practical starting point is w = 5/8 x tp. For example, a 3/8" plate requires at least a 1/4" fillet weld each side. The final weld size must also meet the AISC minimum fillet weld size per Table J2.4 (based on the thinner connected part) and must be verified with the eccentric weld group analysis.

When should I use an extended shear tab instead of a conventional one? Extended shear tabs are necessary when the plate must project beyond the support face -- most commonly when a beam frames into a column web and the plate must clear the column flanges. They are also used when the beam is offset from the support centerline. Extended configurations require more detailed analysis (explicit eccentricity for both bolt group and weld) and have lower capacity per bolt than conventional configurations, but they are unavoidable for column-web framing conditions.

Do I need to check the coped beam at a shear tab connection? Yes. When the beam is coped (flange cut) to clear the support, the reduced cross-section at the cope must be checked for flexural yielding, shear yielding, and local web buckling. The cope creates a stress concentration and reduces the effective section. AISC Manual Part 9 and AISC Design Guide 29 provide the detailed procedures for coped beam checks.

Run this calculation

Use the Steel Calculator tools to design and verify your shear tab connections:

• Bolted Connections Calculator -- bolt shear, bearing, and tearout checks for AISC 360, AS 4100, EN 1993, and CSA S16
• Welded Connections Calculator -- fillet weld capacity and eccentric weld group analysis

Related references

• Steel Connection Types -- overview of simple and moment connections
• Bolted Connections -- comprehensive bolted connection design reference
• Bolt Bearing and Tearout -- detailed bearing and tearout limit state checks
• Bolt Capacity Table -- A325 and A490 bolt capacities
• Coped Beam Design -- checks for coped beams at connections
• Minimum Weld Size -- AISC minimum fillet weld size requirements
• End Plate Connection -- moment end plate design per AISC DG4/DG16
• Steel Connection Design -- general connection design principles
• Connection Ductility -- ductility requirements for steel connections
• How to Verify Calculations -- verification methods for structural calculations

Disclaimer

This page is for educational and reference use only. It does not constitute professional engineering advice. All design values must be verified against AISC 360-22, AISC Manual Part 10, and the governing project specification. Connection design should be performed by a licensed professional engineer. The site operator disclaims liability for any loss arising from the use of this information.

Design Resources

Calculator tools

• Bolted Connection Calculator
• Weld Capacity Calculator
• End Plate Moment Connection Calculator
• Fin Plate Shear Connection Calculator
• Gusset Plate Calculator

Design guides

• Bolted Connection Worked Example
• Bolted Connection Checklist
• Steel Connection Calculator Guide
• Weld Design Checklist
• EN 1993-1-8 Bolted Connection Worked Example

Reference pages

• Shear Tab