Rigging failure

Sorry. Hypoxylon canker on American beech may have comprised the structural integrity of the lead in question. Two arborist blocks were placed in adjacent leads to dissipate the load.
 
N.e.Tree said:
Yes, a little more info on what's going on here please. It's hard to tell from the pic what was trying to be done and what actually happened
Click to expand...
He had two blocks in the tree, in adjacent leads, to dissipate the load. The failure occurred next to the bucket in a patch of hypoxolyn canker. Piece wasn't large although a small amount of dynamic loading took place
 
Did the groundperson let the rope run or tried to catch the piece? Any sense of how far the piece dropped? Size of piece to get an idea of the weight would be helpful too! Thanks!

Good that nobody was injured!
 
The purple dot represents the point of failure. The red dots were where the blocks were placed. Probably could've done a better job spreading the load through the canopy. Maybe even a third block depending on the cut
 

Attachments

  • IMG_5057.webp
    IMG_5057.webp
    191.1 KB · Views: 118
treehumper said:
Did the groundperson let the rope run or tried to catch the piece? Any sense of how far the piece dropped? Size of piece to get an idea of the weight would be helpful too! Thanks!

Good that nobody was injured!
Click to expand...
treehumper said:
Did the groundperson let the rope run or tried to catch the piece? Any sense of how far the piece dropped? Size of piece to get an idea of the weight would be helpful too! Thanks!

Good that nobody was injured!
Click to expand...
10 in beech maybe 6 feet long. Traveled enough to clear the bucket and was slowly stopped 20-25 below.
 
Your boy wasn't really "spreading the load", more like sharing it between two stems at the same side of the crown.
So when the rigging is set up at posted in that picture, the load is going to pull the stems out, towards the left, no matter the size of the load.
If the second block was set on an upright, central lead in the center/closer to right side and at the same height of the block out the left side, it would have caused much less pullijg of that last rigging point where the piece hangs. The set up would cause a more downwards force on the stem with the block.
To illustrate this more, imagine it was set off to the right in the canopy center BELOW the the last block where the piece hangs. The rope angle coming out of that block would have legs heading down towards the ground, pushing down on the stem from the rigging point.

The take away : The wider the rope angles are between at the rigging points, the less force the points see. The more wide angled rigging points you create, the less each point sees as the force is widely distributed.

That's why brothas call me dr dre
 
CutHighnLetFly said:
Your boy wasn't really "spreading the load", more like sharing it between two stems at the same side of the crown.
So when the rigging is set up at posted in that picture, the load is going to pull the stems out, towards the left, no matter the size of the load.
If the second block was set on an upright, central lead in the center/closer to right side and at the same height of the block out the left side, it would have caused much less pullijg of that last rigging point where the piece hangs. The set up would cause a more downwards force on the stem with the block.
To illustrate this more, imagine it was set off to the right in the canopy center BELOW the the last block where the piece hangs. The rope angle coming out of that block would have legs heading down towards the ground, pushing down on the stem from the rigging point.

The take away : The wider the rope angles are between at the rigging points, the less force the points see. The more wide angled rigging points you create, the less each point sees as the force is widely distributed.

That's why brothas call me dr dre
Click to expand...
I think I follow. What if the blocks were installed where the orange dots were
 

Attachments

  • IMG_5057.webp
    IMG_5057.webp
    191.3 KB · Views: 64
This is applied physics. YOu'd be well served to learn about vector analysis. Simply put a vector is force with a direction. When you learn this you'll understand the effect of angles in a system.
 
You must log in or register to reply here.

New threads New posts

Back
Top Bottom