Concrete and Masonry

DUC series


Reference Series: -- --
DUCs are mechanical anchors expanded into holes that have been undercut at the bottom using an undercutting drill bit. This creates a true bearing type anchor that performs like a cast-in-place headed anchor. Load is transferred into the concrete through bearing, not friction like traditional expansion anchors. Excellent performance in seismic and dynamic loading conditions. Meets ACI 318-14 Chapter 17 (2018 IBC) requirements as a code anchor, including seismic loading, tension zone, and cracked concrete provisions.

DUC Undercut Anchor Advantages vs. Heavy Duty Sleeve and Expansion Anchors and other undercut systems:

• DUC Undercut design provides consistent expansion and is easy to set. Stress risers have been eliminated to prevent tearing.
• Large bearing area provides exceptional performance even in lower strength concrete.
• Load transfers mainly through bearing, not expansion forces and is not dependent upon friction which can be lost when cracks occur.
• Thick walled sleeves transfer load over a larger area which insures predictable ductile performance.
• ASTM A36 or A193 grade B7 rods are used. Full ultimate steel strength of the threaded stud is developed at listed embedment and spacing. Stainless steel is also available.
• Installation is simple. It is similar to installing a typical expansion anchor; no coring drills are necessary. Creation of proper undercut is correctly done and easily verified using DUC Undercut Bits. Creation of undercut takes only seconds.

Materials: Rod Materials: ASTM A36 (L Series), A193 Grade B7 (H Series), or AISI 316 Stainless Studs Anchor Body Materials: ASTM A 513 Type 5, or AISI 316 Stainless
Code Reports: View Code Report Table

Technical Bulletins


  • 1. Drill the hole to proper depth and diameter per specifications using rotohammer and stop drill bit.
  • 2. Clean the hole using a blow-out bulb or compressed air.
  • 3. Insert the undercut bit and start rotohammer. Undercutting is complete when the stopper sleeve is fully compressed (gap closed).
  • 4. Clean the hole again using a blow-out bulb or compressed air.
  • 5. Insert anchor into hole. Place setting sleeve over anchor and drive the expansion sleeve over the expansion coupling.
  • 6. Verify that the setting mark is visible on the threaded rod above the sleeve.
  • 7. Apply proper torque.

Need Help or Have a Question? Contact Customer Service or Call 800-328-5934

Load Table

Tension and shear capacities for DUC Anchors in f1c > 2,500 psi concrete
Undercutter Bits for DUC Undercut Anchors
Replacement Parts for DUC Undercutter Bit