What size and shape of steel tubing is needed for a belay bar on a slackline?

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Discussion Overview

The discussion revolves around determining the appropriate size and shape of steel tubing needed for a belay bar on a slackline. The context includes considerations of safety, load-bearing capacity, and structural integrity, with a focus on practical application rather than theoretical analysis.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant outlines the project requirements, specifying a maximum load of 500lbs and a maximum fall distance of 18 inches.
  • Another participant inquires about the original poster's mechanical background and the methods for securing the poles, suggesting the use of a sliding pulley for better safety management.
  • The original poster provides details about their background in architecture and construction, and mentions the current state of the poles and ground conditions.
  • The idea of incorporating a pulley system is proposed as a means to enhance safety during use.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the specific size and shape of the tubing required. There are multiple considerations and suggestions regarding safety features and structural support that remain unresolved.

Contextual Notes

Participants have not fully addressed the implications of the load and fall distance on the design, nor have they provided detailed calculations or specifications for the tubing. The discussion also lacks clarity on the bracing of the poles and the overall stability of the setup.

Who May Find This Useful

This discussion may be useful for individuals interested in DIY projects involving slacklines, safety engineering, or those with a background in construction and mechanical design.

josephd
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I am trying to complete a project and have to properly size some steel tubing. The project is a belay bar for a slackline we have in the yard.

I have 2 poles that are set in the ground 21' apart and a slackline runs between them. We want to run a steel tube beam, permanently attached to the posts, that will act as structure to attach a belay line to the kids in case they fall off.

Ive attached a sketch of the set-up. The belay line will attach around the tube and to a harness the kids wear.

I'm figuring the max load at 500lbs and max fall distance at 18". I'm not sure I've given all the info needed but I do appreciate any help.

My question is what size tubing do we need and what shape would work best?

steel tube.jpg
 
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Thread closed temporarily for Moderation...
 
Thread re-opened.

Welcome to the PF. We try to be careful about allowing discussions of potentially dangerous activities, so the Mentors needed to discuss your thread a bit before it could be re-opened.

Can you say a bit about your mechanical background? From your sketch, it looks like you at least have training in drafting, and maybe more.

How are you planning on securing and bracing the two end poles? Are you going to have a sliding pulley on the belay bar, to make it easier to keep the belay loop over the person walking on the slackline? What is the ground like under the slackline? Concrete, grass, sand?
 
Thanks for the reply.
So, a bit about my background: I have a Bachelor of Architecture Degree that hasn't been used for 15 years. ;)
I have experience in construction and welding, but not expertise.

The two poles are in the ground 6'-6" and are old telephone poles. They are currently not braced at all and the slackline is being used.
The ground under has a built up bed of pea gravel approx 8" deep.
A pulley sounds like a great idea. I would like to have some sort of pulley to aid the belay staying over the person.

Right now my kids and friends are using the line I'm just trying to reduce the chance of injury.
 

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