Headed & Shear Connector Studs
What are headed and shear connector studs? These are drawn arc weld studs with an upset head, welded directly to steel and then embedded in concrete. The same basic product does two different structural jobs. Headed concrete anchor studs, in 3/8 through 5/8 inch, weld to an embed plate and anchor steel into concrete. Shear connector studs, in 3/4 and 7/8 inch, weld to a beam flange and make the beam and slab act as one composite member. Anchoring a plate, you want the smaller diameters. Building a composite beam, you want the larger ones. AlbanyCountyFasteners.com stocks both in plain steel.
Headed concrete anchors vs shear connectors
They look nearly identical, and they are not interchangeable. Both are headed drawn arc studs in ASTM A108 carbon steel qualified under AWS D1.1, so the difference is what they do and which code governs them. A headed concrete anchor is an embedment anchor: welded to an embed plate or bearing plate and cast into concrete, it holds steel to concrete under tension and combined loading, and it is designed under ACI 318. A shear connector is a composite construction element: welded to the top flange of a beam and embedded in the slab poured above, it transfers horizontal shear so the two work as a single section, and it is specified under AISC 360. If a drawing calls for shear connectors, substituting anchors is a specification change, not a swap.
What are headed concrete anchor studs?
Headed concrete anchor studs, often shortened to HCA, develop their capacity through mechanical bearing. Once the concrete cures around the head, pulling the plate away means dragging that head through the slab. That is why capacity depends far more on embedment depth, edge distance, and anchor spacing than on the stud itself, and why failure is usually a cone of concrete breaking out rather than steel fracturing.
- Stocked in 3/8, 1/2, and 5/8 inch diameters
- Welded to embed plates, bearing plates, and base plates
- Designed primarily for tension and combined tension and shear
- Governed by ACI 318 Chapter 17 concrete breakout provisions
- Used in precast and cast in place concrete work
What are shear connector studs?
Shear connector studs make composite action possible. Without them, a slab sitting on a beam is just a load the beam carries, and the two surfaces slip against each other as it deflects. Weld connectors between them and that slip is prevented, so the slab works in compression as part of the section and the assembly bends about a combined neutral axis. The result is a substantially stiffer, stronger member from the same steel, which is why composite design reduces beam depth and steel tonnage in a floor system.
- Stocked in 3/4 and 7/8 inch, the standard construction diameters
- Welded to the top flange of a beam, embedded in the slab above
- Transfers horizontal shear between steel and concrete
- Specified under AISC 360, qualified as AWS D1.1 Type B
- Equal shear strength in all directions, with minimal obstruction to slab reinforcement
How drawn arc stud welding works
- The stud loads into the gun chuck with a ceramic ferrule held around its base
- The gun presses against the work and lifts the stud to strike an arc
- The arc melts the stud tip and a pool in the base metal, contained by the ferrule
- The gun plunges the stud into the pool and the metal fuses
- Once cool, the ferrule is broken away to expose the weld fillet
- Studs are listed at length before weld, since the process consumes part of the tip
Common applications
- Composite floor construction in steel framed buildings
- Bridge deck construction on steel girders
- Embed plates and bearing plates in precast concrete
- Cast in place structural steel to concrete connections
- Equipment bases, handrail posts, and machinery anchorage
- Parking structures, mezzanines, and composite box beams
Every drawn arc weld consumes a ferrule, so order matching ceramic ferrules alongside your studs. Background on the welding process and the full stud range is on our weld studs page.
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Headed & Shear Connector Stud FAQs
Which do I need, an anchor or a shear connector?
Look at what you are welding to. A plate that will be cast into concrete takes headed concrete anchors. A beam flange with a slab poured over it takes shear connectors. If you are working from a structural drawing, it will name one or the other, and that is a specification rather than a description.
Can I substitute one for the other?
Not where a drawing specifies. Diameter is a design input to the shear transfer calculation, so changing it changes the required stud count and layout. Any substitution on a structural connection needs the engineer's approval.
What is AWS D1.1 Type B?
AWS D1.1 classifies studs by type. Type A covers general purpose studs where shear transfer is not the primary function. Type B covers headed, bent, or otherwise configured studs used as an essential component in composite beam design, carrying higher minimum mechanical properties including greater elongation.
Why is the stud shorter after welding?
The process consumes part of the tip. Studs are specified at length before weld, with the reduction depending on diameter, roughly 3/16 inch on 3/4 and 7/8 inch studs. Welding through metal deck consumes more, closer to 3/8 inch.
Do I need a ferrule for every stud?
Yes. Standard ceramic ferrules are single use, cracked by the thermal shock of the weld and broken away afterwards to expose the fillet. Order one per stud plus a margin for handling breakage.
Can I use capacitor discharge welding?
No. CD welding suits small diameters on thin base material, generally 1/4 inch and below. These diameters require the drawn arc process, which produces the full penetration fusion weld that AWS D1.1 mechanical requirements depend on.
How many studs does a composite beam need?
That is a design output calculated by the engineer of record from the horizontal shear the connection must transfer under AISC 360. Stud count, spacing, and layout come from the structural drawings.