ANCHORS > Ultraplus Undercut
The undercut anchor for exceptionally high
loads in cracked and non-cracked concrete – also for shock and earthquake loads.
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
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
Nuclear power plants
Positive undercut anchor with
Expansion pressure free
strong mechanical interlock
Small edge distances and spacings
Dependable fixing for high loads in cracked and
High safety margins due to positive
High strength threaded rod – Grade
The spring automatically compensates for tolerances
in the fixture thickness
Reduced edge distances and
Custom lengths available
Proven performance history in resisting dynamic
loads, shock loads, and earthquakes. Expert reports available for these and other
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
Cracked and non-cracked concrete: C20/25 to C50/60
ETA-04/0099 – Option 1 – Carbon steel, zinc plated.
Tension: Nperm = 19.0 - 320.2 [kN]
Shear: Vperm = 45.2 - 371.4 [kN]
UP: M12 – M36, carbon steel, zinc plated and blue passivated.
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.
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
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.
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).
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.
The permissible bending moments are only valid for
the threaded stud (e.g. in case of a distance mounting).
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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