Prepper engineering: card #2 - The Bridge

[1krr]

So I was going to try to do these weekly but a combination of cabin fever, a nice (but damn windy day) and a need I have made me think of this one. And this one will get a build post associated with it!

There has been a large storm system move through and you have no power, a couple of cans of fuel and good compliment of tools. You have a chainsaw and an ATV and a small trailer. You live in a rural wooded area and a large tornado has pushed over trees onto your only otherwise passable road making it impossible to drive out. A loved one has suffered severe injuries and you have stablized them. You need to get them to a hospital. You have a field to the back of your house that has a creek running through it and to the other side is a pasture and is open enough to get to a road about a mile away. The near by cell tower has been damaged and there are no land lines and only a couple of neighbors. You have no wireless communication such as a ham or CB. You feel like your loved one is stable enough to move but if they don't get to a triage center quickly, you fear for their life.

Your fastest plausible exit is via the field to the other road but you need to cross the creek to get to the otherwise fairly open path. The creek is steeply banked and about 6 feet deep with just a trickle running through the bottom. The narrowest span is about 12 feet. Your job is to design a method using only what you have round you to cross that creek with the ATV and get to the other side of the road in hopes of getting help. Game on!

 

[becker_atc]

Use my tools to dig out the bank so the atv can go down and up the banks. Creating a low water crossing like this would be safer and faster in my mind. A bridge wouldn't be something I want to build in a hurry.


Sent via message in a bottle

 

[easy]

Use chainsaw and clear road?

 

[1krr]

Should be clearer to say that a really big tornado pushed a lot of large mature trees from your heavily wooded land onto the road for a good fraction of a mile.

 

[Johnjosiah]

seems like you would have to move several yards of dirt for a 6 foot drop to make a decent slope. like 125cubic feet for 6 foot wide 60 degree slope???... been awhile since trig. I would want to use at least 16 foot long post to span 12 feet. this is hairy to...seems it would sag a lot in the middle. might try to lash some post together that would cross but not sure I could lift anything heavy duty enough to hold atv and 2 people. Next would be dig a partial slope then use post to angle to the bottom then repeat the other side. Lash the bottom ends and use side of dug hole to hold post in place at top. Nothing seems too good so far. I'll have to keep thinking. Center support to span the whole thing would help but engineering might be tougher.

 

[aviator41]

perhaps it would be best to find a spot on the creek where the banks aren't so steep then cross there. It would be easier to make a trail to that point than to try and build a bridge in a hurry and risk the injured person, the driver AND the ATV all at the same time.

If your road is that badly damaged and impassible, whats to say other roads haven't suffered the same fate? So, even if you get across the creek, it could all be for nothing, then you have a useless bridge, dead relative and less fuel.

 

[oneof79]

Just cut logs, roll them into the creek until it was full enough to drive over.

 

[securitysix]

Should be clearer to say that a really big tornado pushed a lot of large mature trees from your heavily wooded land onto the road for a good fraction of a mile.

You're saying that the notion of this exercise is that it is faster to design and build a bridge sturdy enough to carry an ATV, a small trailer and 2 people across a 6 foot deep, 12 foot wide ditch than it is to cut a vehicle wide swath through the trees blocking the road? And either way, you're trying to do this to rush someone to medical care, yes?

If you truly have them stabilized, you've got time to clear the road, which is a far safer option than trusting some bubba-engineered bridge.

If they're less "stabilized" and more "dying much slower", I'd look for a better place to just ford get into and out of the creek, even if it meant cutting a few neighbors' fences and fixing them later.

If I just had to quickly build a bridge that I could drive an ATV and trailer across, I'd dig a step into either side of the bank. These "steps" would be as deep as the thickness of the trees you'll be using for the bridge. They should each come a foot or two back from the bank, and they should each be at least a tree diameter, preferably two, wider than your ATV. Then I'd fell some sturdy trees that are long enough to span the gap, cut them to fit inside the steps, trim off any limbs, brushy twigs, or other things that would get in the way, and lash them together with some rope/para cord/sturdy vines, especially around the middle, to keep them from separating (the steps at either bank should hold the ends together).

Ideally, this setup would keep the tree trunks from shifting toward one bank or the other because they're cut to length, should keep them from rolling side to side because they're held in at the ends by the steps and tied together at intervals toward the middle, and would keep you from having to drive up/down onto or off of them.

Then, as I attempted to drive myself and my injured loved one across the bridge, I would pray that God thinks this is a better idea than I do and holds up the bridge until I'm across.

Of course, if you have time to build a bridge before someone's injured, you could take the time to do it right, and build a proper bridge with structural support and actual engineering behind it.

 

[Oklahomabassin]

In these parts, I would cut the 3 trees on the mile line to clear the roadway and drive on.

 

[streak]

forget a bridge, Turn the small trailer into ramp, Jump the creek get to a phone and call for a hellicopter