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Zip Line Anchors



Zip Line Anchors


What can I use to anchor my zip line?


Disclaimer We have gleaned some helpful information about setting anchors from our own experience as well as the ACCT Standards for challenge courses and zip line tours. Keep in mind that these are general guidelines and can never replace the value that a local arborist, contractor or engineer could provide to your specific location.

DO NOT USE
  • Buildings or playground structures (unless specifically built for zip lines),
  • power/telephone poles,
  • dead trees or stumps, trees with rot,  disease, structural cracks, excessive lean, exposed roots,
  • or trees in boggy, wet, sandy, loose soil.
This is only a partial list. You must use your good judgment in determining what is NOT an appropriate anchor point. If in doubt, email an expert at ziplinestop@yahoo.com

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TREES
  • Tree Trunks must have a 12-inch diameter, minimum. Do not attach to any limbs/branches other than a central Trunk.
  • Protecting your tree's health will preserve its structural integrity. By placing Tree Saver Blocks between your cable and your tree, you will provide this barrier of protection. Because the living, vital part of a tree is the thin layer under the bark, a tree can slowly starve if constricted by cable. It may take years to notice the damage, but fewer leaves and/or fewer branches are eventual collateral. We've seen tree-houses and zip lines completely kill their host trees. Dead trees become a safety hazard. Watch out the health of your beautiful tree.
  • Flash flooding, and erosion can make a once reliable tree a hazard.
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• DO NOT partially imbed an Eye Lag screw into your tree and expect it to hold a zip line and rider. Eye Bolts are technically less invasive to a tree's health than wrapped cable and they are an acceptable anchor method. The bolt must penetrate the trunk entirely to be reinforced with a washer and nut on the back. 
POSTS
  • Wood or Metal posts must be 12” diameter, minimum.
  • Posts must be sunk 4 feet in ground, or 10% of post length plus 2 feet (whichever is greater). Secure with concrete 6 inches thick around post. Soil media such as sand, rock or high ground water environments may require alternative installation techniques and consultation with an engineer.
  • DO NOT partially imbed an Eye Lag Bolt into your post and expect it to hold a zip line and rider. Eye Bolts are recommended for posts. The bolt must penetrate the post entirely to be reinforced with a washer and nut on the back. 
  • For wooden posts, eye bolts or slings should be anchored 12” or lower from the top of the post.
Ask your local power company about "retired" power poles. Sometimes you can purchase these by the foot and they may even be able to auger the hole and drop the post in place for you as well, making the installation process a breeze.

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Guy wires, Penetrator Earth Anchors

Additional depth, bracing, or guy wires may be needed for soft or unusual soil types.
  • Supported poles can be a minimum of 8" diameter. These poles must be anchored via cable (i.e. guy wires) to other poles or ground anchors.
  • For wooden posts, eyebolts or slings should be anchored 12” or lower from the top of the post.
  • Posts must be sunk 4 feet in ground, or 10% of post length plus 2 feet (whichever is greater). Secure with concrete 6 inches thick around post. Soil media such as sand, rock or high ground water environments may require alternative installation techniques and consultation with an engineer.
    
Some recommended penetrator ground anchors for utility poles are the Screw and the Arrowhead
When in doubt, a local contractor is usually a good resource for understanding soil types in your area. 
PE46_Guy_Holding_Utility_Pole_For_Zip_Line.jpg   wood zip line zipline ramp landing plans cable structure anchor free standing rubber tire stop end brake
Dimensional Lumber Anchors
In some circumstances when the necessary anchoring height is not very high, dimensional lumber may be appropriate for constructing a launching or landing anchor. A typical design will incorporate two 12’ treated 8x8’s concreted into the ground 4’ deep with a beam spanning the two posts, like a door frame. The zip line cable is anchored to the crossbeam, and the frame is either supported from the back with guy-wires, or from the front with additional posts bracing the frame at a 45 degree angle.
Structures
Most buildings or backyard play structures are not designed to withstand the horizontal loading of a zip line cable. Design or retrofit accordingly to ensure your structure is not damaged and participants are not put at risk. 
Would you like more information? Check out this blog: How to Build a Zip Line

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