Treehouse bridge update: one section blew down in the California storms

[Danny D.]

The third section blew down in the California storms.

It was just the frame, and a few deck timbers:

Apparently the mistake was to attach it here to the redwood:

These two smaller redwoods apparently bowed to the sides:

We had only the far end attached to the steel cable:

So, we think the mistake was to trust the redwoods and not attach the close end to the overhead steel cable, and also that we had attached the far ends to the cable temporarily with just rope, which broke when the redwoods splayed out in the winds.

What we think happened was:

1. The redwoods splayed outward, pulling the boards out.
2. The close end fell downward putting pressure on the far end.
3. The rope on the right side of the far end broke under stress tumbling the boards to the steep hillside below:

We still can't get the dog out onto the bridge yet, though:

:)

[G. Ross]

It's hard to build in flexibility.

[woodchucker]

Your mistake was using multiple trees. Had you made the tree house using one it would survive, putting it between trees that naturally sway is well, disregarding that fact. Poor design.

[DerbyDad03]

My dog is reluctant to cross any bridge that he can see through. For exampl e, we have a grated swing bridge that is swung across the opening between a bay and a lake during the winter months. When the bridge is across the ope ning, I practically have to drag him across. When it is swung against the s hore and used as a fishing pier during the summer, he doesn't want to walk on it even though it's only about 5' above the water.

When we hike through the woods, he hesitates at any type of bridge that doe s not have a solid walkway. He doesn't seem to be afraid of heights, since he will stand at the edge of "cliff" or on the wall along a gorge walkway, etc.

I'm not sure what's going through his head but it's petty consistent when i t comes to bridges.

[woodchucker]

Or putting it between ground and a tree static and swaying also wrong. There's no way for this to survive.

Any storm with potential to sway the tree will rip it apart.

[John Larkin]

The winds were vicious yeaterday. Driving back to SF, somewhere around Vallejo, a huge multi-trunk tree blew onto I80 and blocked traffic for miles. Westbound, traffic was blocked by the trees, and eastbound, it was blocked by idiots.

Here's The Brat, the kid what does our PCB layouts.

The wind chill up there was in single digits up there on Monday, and predicted -20F in places on Tuesday night. They can get 100 MPH gusts up there on the peaks. Sunny California.

[dpb]

On 12/31/2014 9:19 AM, DerbyDad03 wrote: ...

Same principle as the cattle guard...all it takes is an apparent opening that they can't perceive they might not step into. One can even dispense with the pit and grate entirely and simply paint lines on a road surface...

[-MIKE-]

I think the canine is the smarter of the species in this case. :-D

[Maynard A. Philbrook Jr.]

I think the dog is smarter !

Jamie