Concrete screw with countersunk head W-BS/A4
Concrete screw W-BS type SK, stainless steel A4
CONCSCR-(W-BS/SK)-A4-TX50-5-35-10X90
![](https://media.wuerth.com/source/eshop/stmedia/wuerth/images/std.lang.all/resolutions/category/78px/819973.jpg)
![](https://media.wuerth.com/source/eshop/stmedia/wuerth/images/std.lang.all/resolutions/category/78px/4718153.jpg)
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![](https://media.wuerth.com/source/eshop/stmedia/wuerth/images/std.lang.all/resolutions/category/78px/574255612.jpg)
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- Extremely flexible to use due to three anchoring depths (size 6-10)
- Fastening can be adjusted up to twice after installation (size 6-10), for example in order to align railings or anchor plates (please refer to the assembly guide)
- Very high loads
- Smallest axial and edge clearance due to very low expansion effect
- Very fast and easy assembly and immediately load-bearing
- Attractive, flush-mount installation possible
European Technical Assessment ETA-16/0043 for fixing point, option 1, cracked and non-cracked concrete:
- Static and quasi-static effects (∅6 - ∅10)
- Seismic effect, performance category C1 (∅6 - ∅10)
- Fire resistance R30, R60, R90, R120
European Technical Assessment ETA-16/0128 for anchors in a redundant non-structural system:
- Cracked and non-cracked concrete, (∅6)
- Hollow-core prestressed concrete ceilings C30/37 - C50/60, (∅6)
- Fire resistance R30, R60, R90, R120
DIBt National technical approval/general type approval Z-21.1-2075 as bonded screw anchor for anchoring in concrete (∅10, type S hexagon head)
- Use in combination with injectable mortar WIT-BS as bonded screw anchor WIT-BS
- In reinforced and non-reinforced and cracked and non-cracked concrete C20/25 to C50/60
Tensile capacity in concrete hollow body ceilings, (∅6 - ∅10) - expert report no. 21641 - 2016
Fire resistance rating when exposed to fire according to the uniform temperature time curve in masonry (Mz, KSL, KS), and reinforced concrete, (∅6) - expert report no. 2101/173/18 - 2018
From size 8, we recommend the use of a suitable tangential impact screwdriver for installation. The recommended nominal torque must be observed. When used outdoors, the drill hole can be sealed with WIT-BS injectable mortar.
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/normal/348px/4206421.jpg)
Railings
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/normal/348px/4206422.jpg)
Handrails
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/normal/348px/4332957.jpg)
Adjustment - subsequent aligning possible
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/37435254.jpg)
Create the drill hole
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162590.jpg)
Clean the drill hole
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162589.jpg)
Place screw
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162588.jpg)
Screw in the screw
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162587.jpg)
Considered installed when the head is close fitting
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162586.jpg)
Screw out the screw max. 2x each by max. 10 mm. Underlay. Screw in
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162592.jpg)
Considered installed when the head is close fitting. Lining max. 10 mm. The required embedment depth must be maintained as a minimum
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662258.jpg)
Locate the tensioning strand
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662259.jpg)
Mark the tensioning strand and locate the next one
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662260.jpg)
Mark the tensioning strands. Specify the drilling range
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662261.jpg)
Create the drill hole. Observe spacing
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662262.jpg)
Clean the drill hole
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662263.jpg)
Screw in the screw
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662264.jpg)
Considered installed when the head is close fitting. Observe the embedment depth/mirror thickness
European Technical Assessment ETA-16/0043 for fixing point, option 1, cracked and non-cracked concrete:
- Static and quasi-static effects (∅6 - ∅10)
- Seismic effect, performance category C1 (∅6 - ∅10)
- Fire resistance R30, R60, R90, R120
European Technical Assessment ETA-16/0128 for anchors in a redundant non-structural system:
- Cracked and non-cracked concrete, (∅6)
- Hollow-core prestressed concrete ceilings C30/37 - C50/60, (∅6)
- Fire resistance R30, R60, R90, R120
DIBt National technical approval/general type approval Z-21.1-2075 as bonded screw anchor for anchoring in concrete (∅10, type S hexagon head)
- Use in combination with injectable mortar WIT-BS as bonded screw anchor WIT-BS
- In reinforced and non-reinforced and cracked and non-cracked concrete C20/25 to C50/60
Tensile capacity in concrete hollow body ceilings, (∅6 - ∅10) - expert report no. 21641 - 2016
Fire resistance rating when exposed to fire according to the uniform temperature time curve in masonry (Mz, KSL, KS), and reinforced concrete, (∅6) - expert report no. 2101/173/18 - 2018
Datasheets(X)
Fixing point with approval (∅6 - ∅10):
In normal weight concrete C20/25 to C50/60 (cracked and non-cracked concrete)
Anchors in a redundant non-structural system, with approval:
- In normal weight concrete C20/25 to C50/60 (cracked and non-cracked concrete, (∅6))
- In hollow-core prestressed concrete ceilings C30/37 - C50/60, (∅6)
Specifically designed for surface-flush, visually appealing mounting
Suitable for fastening medium to heavy loads in concrete:
- Attachment of e.g. staircase railings and balcony balustrades, handrails, steel constructions, wooden substructures, metal profiles etc. in in-place installation
- Fastenings under seismic conditions in earthquake areas
- Fastenings under exposure to fire
W-BS/A4 (stainless steel A4) can be used in dry indoor conditions, outdoors (including in industrial atmospheres and coastal areas) or in wet rooms, provided that no particularly aggressive conditions are present
For use in concrete < C20/25 and pressure-resistant natural stone (without approval)
Anchor size | 10 mm |
Anchor length (l) | 90 mm |
Attachment height (t fix 1) | 35 mm |
Attachment height (t fix 2) | 15 mm |
Attachment height (t fix 3) | 5 mm |
Thread diameter | 12 mm |
Nominal drill-bit diameter (d 0) | 10 mm |
Drill hole depth (h 1.1) | 65 mm |
Drill hole depth (h 1.2) | 85 mm |
Drill hole depth (h 1.3) | 95 mm |
Embedding depth (h nom1) | 55 mm |
Embedding depth (h nom2) | 75 mm |
Embedding depth (h nom3) | 85 mm |
Head diameter (d sk) | 22 mm |
Internal drive | TX50 |
Head type | Countersunk head |
Material | Stainless steel A4 |
Through-hole in the component to be connected (d f) | 14 mm |
Surface | Plain |
Type description | W-BS A4 type SK |
Anchor size [mm] | 6 | 8 | 10 | |||||||
Admissible load when exposed to fire (R30, R60, R90, R120), see European Technical Assessment ETA-16/0043 | ||||||||||
Performance data in concrete - fixing point according to ETA-16/0043 | ||||||||||
Length of anchor in drilled hole | hnom [mm] | 40 | 55 | 45 | 55 | 65 | 55 | 75 | 85 | |
Admissible centric tension load1) on an individual anchor without the influence of the edge distance | Tensile zone (cracked concrete C20/252), s ≥ 3 hef c ≥ 1.5 hef) | Nperm. [kN] = C20/252) | 1,0 | 1,9 | 2,4 | 4,3 | 5,7 | 4,3 | 8,0 | 9,6 |
Compressive zone (non-cracked concrete C20/252), s ≥ 3 hef c ≥ 1.5 hef) | 1,9 | 4,3 | 3,6 | 5,7 | 7,6 | 5,7 | 9,5 | 11,9 | ||
Admissible shear load1) on an individual anchor without the influence of the edge distance | Tensile zone (cracked concrete C20/252), c ≥ 10 hef) | Vperm. [kN] = C20/252) | 3,0 | 3,3 | 3,6 | 4,8 | 6,4 | 4,8 | 15,9 | 16,2 |
Compressive zone (non-cracked concrete C20/252), c ≥ 10 hef) | 3,3 | 3,3 | 5,0 | 6,8 | 8,1 | 6,8 | 16,2 | 16,2 | ||
Permissible bending moment | Madm [Nm] | 4,8 | 12,4 | 26,7 | ||||||
Admissible load under seismic activity performance categories C1 and C2 see European Technical Assessment ETA-16/0043 | C1 | x | x | x | x | x | ||||
C2 |
Performance data in concrete - anchors in a redundant non-structural system according to ETA-16/0128 | ||||
Anchor size [mm] | 6 | |||
Length of anchor in drilled hole | hnom [mm] | 35 | 55 | |
Anchors in concrete in a non-structural system based on a redundant design3) | Nperm. [kN] ≥ C20/25 | 0,6 | 3.64) | |
Admissible shear load1) on an individual anchor without the influence of the edge distance | Tensile zone (cracked concrete C20/252), c ≥ 10 hef) | Vperm. [kN] = C20/252) | 2,0 | 3,3 |
Compressive zone (non-cracked concrete C20/252), c ≥ 10 hef) | 2,8 | 3,3 | ||
Permissible bending moment | Madm [Nm] | 4,8 | ||
Admissible load when exposed to fire (R30, R60, R90, R120), see European Technical Assessment ETA-16/0128 |
Performance data for hollow-core pre-stressed concrete ceilings - multiple attachment | ||||
Anchor size [mm] | 6 | |||
Mirror thickness [mm] | ≥ 25 | ≥ 30 | ≥ 35 | |
Anchors in a redundant non-structural system in hollow-core prestressed concrete ceilings5) | Fperm. [kN] | 0,4 | 0,8 | 1,2 |
1) The partial safety factors of the resistances γM regulated in the evaluation/approval and a partial safety factor of the effects of γF = 1.4 have been taken into account. For a combination of tensile and shear loads, for the influence of the edge distance and anchor groups please see the appropriate guidelines e.g. DIN EN 1992-4. 2) The concrete has normal reinforcement. Higher values are possible for higher concrete strengths. 3) The admissible loads were determined without axial influence and the influence of the edge distance. 4) Number of attachment points ≥ 3 and at least one anchor per attachment point produces a load per attachment point of Fperm ≤ 1.4 kN or number of attachment points ≥ 4 and at least one anchor per attachment point produces a load per attachment point of F≤perm 2.1 kN. The admissible loads can be increased if the design shows that the requirements governing the strength and rigidity of the component to be attached remain satisfied even after the failure of an anchor in terms of the limit state of serviceability and load-bearing capacity. 5) The assembly data must be observed. |
Installation parameters in concrete | ||||||||||
Anchor size [mm] | 6 | 8 | 10 | |||||||
Length of anchor in drilled hole | hnom [mm] | 351) | 40 | 55 | 45 | 55 | 65 | 55 | 75 | 85 |
Minimum axis distance | smin [mm] | 35 | 40 | 40 | 50 | 50 | ||||
Axis distance | scr,N [mm] | 81 | 93 | 132 | 105 | 129 | 156 | 129 | 180 | 204 |
Minimum edge distance | cmin [mm] | 35 | 40 | 40 | 50 | 50 | ||||
Edge distance | ccr,N [mm] | 40,5 | 46,5 | 66 | 52,5 | 64,5 | 78 | 64,5 | 90 | 102 |
Minimum member thickness | hmin [mm] | 80 | 100 | 100 | 120 | 100 | 130 | |||
Nominal drill diameter | d0 [mm] | 6 | 8 | 10 | ||||||
Diameter of cutting edges | dcut ≤ [mm] | 6,40 | 8,45 | 10,45 | ||||||
Drill hole depth | h1 ≥ [mm] | 40 | 45 | 60 | 55 | 65 | 75 | 65 | 85 | 95 |
Through hole in the component being connected | df ≤ [mm] | 8 | 12 | 14 | ||||||
Internal drive | TX30 | TX40 | TX50 | |||||||
Head diameter | dsk [mm] | 13 | 20 | 22 | ||||||
Max. rated torque of tangential impact screwdriver | Timp,max [Nm] | 10 | 20 | 40 | ||||||
1) For anchors in a redundant non-structural system |
Anchor size [mm] | 6 | |
Through hole in the component being connected | df ≤ [mm] | 8 |
Installation parameters in hollow-core prestressed concrete ceilings | ||
Minimum axis distance | smin [mm] | 100 |
Minimum edge distance | cmin [mm] | 100 |
Minimum spacing between the groups of anchors | amin [mm] | 100 |
Spacing between cavity axes | lc ≥ [mm] | 100 |
Spacing between tensioning strands | lp ≥ [mm] | 100 |
Spacing between tensioning strands and drilled hole | ap ≥ [mm] | 50 |
Nominal drill diameter | d0 [mm] | 6 |