FAQs
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- I need 16mm diameter bars, but haven’t enough cover to accommodate the 50mm thick casing. Why can’t I have 16mm bars fitted into the 36mm thick casing (as used for 10 and 12mm bars)?
Inside the casing, there are generally two layers of bars. In practice, 2 no. 16mm bars, once layered, will measure around 36mm (i.e. apparently equal to the smaller 36mm thick casing). However, two things will happen:
a) the radiused bend of the bar will be completely outside the casing, embedded in the first pour and causing a large misalignment of the bar once rebent and b) the casing lid will become convex due to the bar congestion,
causing much of the unit to become ‘buried’ away from the concrete face (see sketches below).
- If Kwikastrip isn’t feasible for my application, what can I use instead?
In these situations, the Halfen HBM threaded coupler system forms an ideal complement to Kwikastrip. Please ask for details.
- What are the loading differences between Kwikastrip and traditional loose/unbent rebar?
Structural tests (by UK CARES) showed that the flexural and shear strength of construction joints formed with Kwikastrip are no less than those of traditionally formed construction joints.
- If casing lengths are supplied sized to suit my varying length construction joints, how will I identify which individual casing is intended for which construction joint?
A comprehensive labelling system complements the Kwikastrip system. Information such as bar mark and location data is fed from Kwikastrip scheduling forms into a sophisticated computer program, which then automatically adds the overall total number of bars in the joint, the overall joint length, and indicates which part of the joint each individual casing represents, e.g. Unit 1 of 3, 2 of 3 and 3 of 3.
Every single piece of Kwikastrip carries such a label, the content of which is only limited by the amount of information recorded by customers on the Kwikastrip scheduling form. Each label also carries a unique quality system reference, which enables total traceability. The labels are made of waterproof vinyl, which is heat-transfer printed, and are firmly affixed to Kwikastrip lids.
- The normal bar supply range is B10, B12 and B16. Why can’t you supply B08, B20, or even larger?
B08 has become a non-preferred size in the UK, leading to a lack of availability. Halfen ordinarily substitutes B10 when B08 is (very occasionally) requested. Size B20 (and above) is beyond sensible limits for the system. Problems include: assembled casing weight, increased casing thickness, increased minimum casing length, difficult handling on site, and difficulty in rebending on site.
- What are the longest and shortest individual casing lengths we can supply?
The longest is normally 2.40m. Beyond this, there will be problems of weight, packing, transport, and manageability on site. The shortest length is governed only by the length of lap leg required, i.e. if the pullout lap leg is longer than the casing length which houses it, then there will be nowhere for the legs to go, other than to project out of the casing ends and into the concrete.
As a rule of thumb, the minimum casing length is around double the lap length.