Slackline on garage wall - Structural problem or not?

Hello guys, I have a garden, unfortunately without big trees. But I want to tighten my slackline to walk a bit again. I thought about attaching the line to two garages (my own). One is built (sand-lime brick + clinker), the other is a prefabricated garage made of reinforced concrete slabs. With a slackline, tensile forces of up to 1.5T can occur (worst case). The attachment itself would not be a problem: hole through the wall, a steel plate on the inside and then a threaded rod through the wall with an eyelet on it. My problem: I’m afraid that the masonry/concrete slabs won’t withstand the tensile force of 1.5 tons. The attachment points would each be at the corner of the garages, i.e. not in the middle of the wall. At a height of about 60cm. Do you think the whole garage wall will move towards me under such a load, or is that no problem for the wall? PS: Please don’t say: get a structural engineer... that would be too much of a hassle for a slackline

Hey! I recently saw that you can also embed hooks into the ground with concrete and then stretch the slackline on different height stands on them. Would that be something?

Yes, I know the method. However, I don't want to have an ugly concrete post standing somewhere when the slackline is not set up. The line between the garages would fit very well there and the hooks would hardly be visible. The only question is whether the prefabricated concrete garage can withstand it. I think I am less worried about the masonry one. It would of course be possible to distribute the force through a larger metal plate inside. But how big does the plate have to be?

No, those are not posts sticking out, but just a hook sticking out. At my acquaintances' place, they concreted it into the ground and put a lid with artificial turf on top. (Used a sewage pipe with a lid) You can't see anything of it when it is dismantled. The slackline itself is then stretched over trestles to the desired height and is then tensioned from the trestle down into the ground. Search for "Bodenanker" in an image search, then you'll find what I mean...

You seem not to know the method, because you speak of a post, but Wildthing refers to a foundation embedded in the ground with an anchor. So there is no post standing permanently, only when the bridge is stretched.

Such a prefabricated garage is designed to accommodate a vehicle resting on about four points with a weight of at most maybe 3 tons (if that much at all). I think it is even less. So at most 750kg per wheel (not centrally) are distributed on the floor area.

The walls serve to support the roof, nothing more, but also nothing less. With about 8cm wall thickness, that is not very generously dimensioned. Such a standard garage probably weighs about 10-12t.

So: you certainly won’t be able to pull the garage away, but what happens if you let your car roll with some momentum against the back wall. Bumper first... that is presumably about 1.5t rolling mass.

I would be very, very, very careful with that, especially since you are aware of the enormous forces involved.

In Austria, a woman was killed who had stretched a hammock between a tree and a really massive statue. She is now dead.

The way to a structural engineer or a statically sufficient fastening unfortunately remains unavoidable. These are not forces that a prefabricated garage can just withstand.

Safety First!

Oh, right, I misunderstood that! There’s probably some truth to it. So I could pour a ground anchor near the prefabricated garage. Do you think the masonry garage would hold the force? The hook would be in the back wall, right next to the side wall. In other words, the tensile force would be transferred to the side wall... so basically force application longitudinal to the side wall...