DYWIDAG Strand Anchors
Strand anchors are assembled from flexible steel wire strand. These anchors are made to order and are installed in one continuous length.
Strand anchors are most commonly used when anchor lengths exceed 20m or when access restrictions prevent solid threadbars from being used.
Strand anchors are supplied to site coiled with a grouted bond length. Strand anchors can be unwound directly into a borehole; this is particularly useful when working in tunnels or basements.
Strand anchors also provide a solution when anchor capacities exceed the strength of the threadbar ranges available. Each 15.2mm compact strand has an ultimate load of 300kN and multiple strands can be incorporated into an anchor. The maximum number of strands used is only dictated by the stressing equipment available to the installer, and capacities of up to 8,000kN have been achieved to date. In a conventional strand anchor, all of the strands begin and end at the same point.
Strand offers more challenges when it comes to stressing the ground anchor due to its increased elongation under load when compared to solid threadbar.
Instead of a thread and a nut, a head block and series of wedges are used to lock off the anchor.