Braces/Wire/Staples

 
      
 
 
 Knowledge Nuggets | Fact Sheets | Research Papers

Knowledge Nuggets

  • Brace assemblies are the foundation of a good fence. The failure of the brace assembly will result in failure of the whole section of fence. Particular attention must be given to the location in suitable soils, depth of post placement, connection of the cross rail to the posts and tying off of the wires.
  • As a brace is an anchor point, it must withstand the load from the fence wires. Under normal conditions, tensioned barbwire fence will exert a pull on the brace of 1,000 to 5,000 pounds. With cold weather contraction, the pull may be as much as 2,500 pounds. In addition, shock loads to the wires such as from livestock or falling trees also must be withstood.
  • A brace must withstand the fence loads by transferring them to the earth. This means a brace is a combination of structure and soil. A brace can fail by the breaking of the posts, tearing the soil as the post moves or by pulling of the post out of the ground.
  • To prevent the end post from being pulled out of the ground the length of the rail between the posts must be as long as is practical. As a rule, the length of the brace should be 2 times as long as the height of the fence. Depending on the needs of the fence, use 6-8” diameter, 8’long posts for end braces. With a “diagonal post” brace design the diagonal post should be set at the height of the fence on the end brace post.
  • Under favorable soil conditions, two-post assemblies are capable of withstanding loads from 3000-6000 lb. of pull and be adequate for fences of 6 wires or less. Three post assemblies are capable of almost double that capacity and should be used in soils of low cohesive properties such as sand, very wet clay or peat soils.
  • High tensile fences are stronger and usually less expensive to build than traditional barbed and woven wire fences. By using a few simple wire handling techniques, they are easier to build.
  • High tensile wire has a greater ability to stretch and return to it’s initial tension and also has a much higher breaking strength than traditional double strand or Monova barb wire. This is particularly important in situations of pushing livestock or wildlife, falling trees or from snow load pressing on the wires.
  • Because high tensile wire is less invasive to animals touching it, fences need more wires than barbed wires in order to provide the same physical effect. High tensile wire fences that contain even one electrified wire, offer effective livestock control.
  • Typically, high tensile wire fences are cheaper to construct than barbwire fences and are resistant to rusting because of the heavier galvanized coating that is normally used on high tensile wire.
  • Although easier to build, high tensile fences require more accessories such as inline strainers than do barb wire fences. However, generally these accessories provide convenience in repairing the fence over the years after construction.
  • The tension on wires is much greater on high tensile fences than on conventional barbed or woven wire fencing. This can put a lot of stress on staples. If staples are the wrong size or driven incorrectly they can pull out.
  • Staples should never be driven all the way in. Enough room must be left so that the wire can move freely to allow the distribution of strain of cold weather and strain from stock running into the fence over the entire fence. Driving staples all the way in increases friction and will result in shorter wire life. It also makes it difficult to tension wire uniformly on long runs, and results in fences less able to absorb heavy livestock pressure.
  • With the exception of curves or corners where wire is passing around the post, staples should not be driven vertically (with the staple points parallel to the grain of the post). This tends to separate the grain and reduces the staples holding power. Rotating staples 20 to 30 degrees off vertical can increase their holding power.
  • One side of each tip of a staple has a flat "slash cut" surface. When a staple is hammered into a post, these slash cuts act as wedges and force legs to curve away from the flat surface. Rotating the staple toward the slash cut will cause the legs of the staple to converge in the post. Rotating the staple away from the slash cut will cause the legs to curve outward. These staples will have about 40% more resistance to pull-out than staples with legs curving in.
  • “Dog legs” in a fence often cause problems with the post at the end of the dog leg tipping sideways. This can be solved by using “dead-man” anchors, double brace assemblies, or constructing 2 totally separate end braces at the dog leg.
Fact Sheets

A Simple Wire Tension Meter - only available in PDF format

Brace Assemblies for Wire Fences - only available in PDF format

Farm Fencing Systems

So You Thought You Know How To Drive A Staple - only available in PDF format

Splices for High Tensile Smooth Fencing Wire - only available in PDF format

Tips for Building a Wire Gate - only available in PDF format

Working With High Tensile Smooth Wire

Research Papers

Let us know of good research papers for this topic.
 
 
 
  For more information about the content of this document, contact Grant Lastiwka.
This document is maintained by Janet Fletcher.
This information published to the web on September 3, 2003.
Last Reviewed/Revised on November 23, 2016.
 

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