The new KSN anchors from Ancon Building Products
are a range of relatively short threaded anchors designed to deliver high performance as reinforcement continuity systems.
A re-bend reinforcement continuity system is currently the most popular method used to connect slabs to walls, wherein bars are supplied pre-bent in a metal box that is cast-in flush with the face of the wall. Upon removal of the formwork the bars are straightened and tied to the main reinforcement.
This method offers a major disadvantage in that the pull-out bar length is limited due to the physical box dimensions and the bar diameter is restricted to that which can be safely re-bent on site.
Alternatively, reinforcement couplers provided with a suitable anchorage bar length are also used for the purpose, wherein the couplers are cast into the wall face and threaded continuation bars screwed in to the coupler once the formwork is removed to make the connection. There is no restriction to the size of the bar that can be used since no on-site bar straightening is required and bars of virtually any length can be screwed into the coupler. On the other hand, it can add to reinforcement congestion in the wall.
A third option is to use cast-in headed anchors, which also accept threaded continuation bar, but this system has been limited by the length of the anchors necessary to achieve the design strength of the reinforcement.
Ancon’s KSN anchors, which have been tested by Ancon and independently verified by leading reinforcement expert, Dr John Cairns of Heriot Watt University in the UK offer enhanced performance when used at slab-to-wall moment connections. The relatively short threaded anchors achieve the necessary performance for a reinforcement continuity system.
Performance data is now available to enable engineers to design construction joints, which eliminate some of the restrictions of traditional continuity systems. Larger bar diameters, shorter boxes and easy installation in heavily reinforced areas are some of the advantages of Ancon’s anchors.
Ancon’s Technical Manager, Gary Connah explains that the company identified an opportunity to increase the pull-out strength of their cast-in anchors where the concrete cone pull-out surface was modified by an adjacent compression force. This enhanced performance is very useful to engineers who are looking for reinforcement continuity systems, which can reduce congestion in the wall, remove bar straightening and allow longer continuation bar length in the slab.