SSI Anchors and Hammer Drill Bits

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Secure Systems International (SSI) Pte Ltd

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MECHANICAL ANCHORS > Ultraplus Undercut Anchor

Undercut Anchor Systems

Ultraplus1  UP with hex nut, washer, threaded stud and plastic retaining ring

The undercut anchor for exceptionally high loads in cracked and non-cracked concrete – also for shock and earthquake loads.


Product Description:

The ULTRAPLUS undercut anchor is designed for use in applications where reliability and safety are essential, e.g. for anchoring safety relevant components in nuclear power plants, for industrial plants, conveyor systems, cranes, and also for special civil engineering solutions.

The ULTRAPLUS was developed to resist very high loads with its unique undercutting technology. After the hole is drilled, a separate undercut is drilled using the special undercutting tool. When the anchor is inserted through the fixture, spring pressure opens the expanding segments. They lock into the undercut with a clearly audible click. The result is a mechanical interlock without expansion stresses. By applying the specified torque, the fixture is fastened in position. The “positive undercut” allows perfect bearing of the segments and ensures reliable transmission of the load into the concrete. 


  • Steel construction 
  • Conveyor systems 
  • Industrial plants 
  • Cranes 
  • Nuclear power plants 


  • Positive undercut anchor with 
  • Expansion pressure free
    strong mechanical interlock
  • Small edge distances and spacings
    Immediately loadable
  • Completely removable
    Through-fix installation


  • Dependable fixing for high loads in cracked and non-cracked concrete 
  • High safety margins due to positive undercutting 
  • High strength threaded rod – Grade 10.9 
  • The spring automatically compensates for tolerances in the fixture thickness 
  • Reduced edge distances and spacings 
  • Custom lengths available 
  • Proven performance history in resisting dynamic loads, shock loads, and earthquakes. Expert reports available for these and other applications. 
  • Positive undercutting (comparable performance to a cast-in headed stud) 


When the anchor is installed the expansion segments are driven down to the undercut in the drilled hole. The spring pressure automatically expands the segments into the undercut with an audible “click.” This results in a mechanicalundercut connection without any expansion pressure. The “positive undercut”allows perfect bearing of the segments and ensures reliable transmission of the load into the concrete.


Grade 10.9 carbon steel, zinc plated and blue passivated.

Base Material:

Cracked and non-cracked concrete: C20/25 to C50/60


ETA-04/0099 – Option 1 – Carbon steel, zinc plated.

Load Range:

Tension: Nperm = 19.0 - 320.2 [kN]
Shear: Vperm = 45.2 - 371.4 [kN]

Product Range:

UP: M12 – M36, carbon steel, zinc plated and blue passivated.




Carbon steel, zinc plated

Carbon steel, zinc plated 

Installation Accessories:

Installation Accessories

Carbon steel, zinc plated:

Permissible loads for single anchors with no infl uencing edge distances or spacings. Loads are calculated using partial safety factors from ETAG 001 and the characteristic anchor and installation data.

Design calculations shall follow the requirements of ETA-04/0099.

Carbon steel, zinc plated

Carbon steel, zinc plated

Installed Anchor:

Installed Anchor

  1. The permissible loads have been calculated using the partial safety factors for resistances stated in the ETA-approval and a partial safety factor for actions of ²F = 1.4. The permissible loads are
    valid for unreinforced concrete and reinforced concrete with a rebar spacing s ≥ 15 cm and reinforced concrete with a rebar spacing s ≥ 10 cm if the rebar is 10 mm or smaller.
  2. The permissible shear loads are based on a single anchor without infl uencing concrete edges. For shear loads applied close to an edge (c ≤ 10 hef or 60 d) concrete edge failure must be checked per ETAG 001, Annex C, design method A. 
  3. Concrete is considered non-cracked when the tensile stress within the concrete is sL + sR £ 0. In the absence of detailed verifi cation sR = 3 N/mm² can be assumed (sL equals the
    tensile stress within the concrete as a result of external loads, forces on anchors included).
  4. If spacings or edge distances become smaller than the characteristic values (i.e. s ≤ scr,N and/or c ≤ ccr,N) a calculation per ETAG 001, Annex C, design method A must be performed. 
  5. The permissible bending moments are only valid for the threaded stud (e.g. in case of a distance mounting). 
  6. This hmin only applies when the remote face of the concrete is inspected to ensure there has been no break-through as a result of drilling. Otherwise hmin = 360 mm (M16) and hmin = 400mm (M20). 

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