Musings on structural integrity

[MickinOz]

His dad...drives a BAB quad, which I do believe I have mentioned on these hallowed pages before.
Pedaling a 74 wheel 4 trailer tri drive semi rig takes a lot out of you...

Mate, I drove semis for 25 years and I think I only understood about 72.1% of that.

America and Australia... two nations separated by a common language.

My son drives this:
It's a cabover Kenworth, with three driving axles, pulling a B trailer, connected to an A trailer, with a B-Double road train connected via a tri-axle converter dolly.
i.e. A tri-drive BAB quad road train. Simple, eh?

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[rjgimp]

On farcebook I follow a trucking company in England called White's Transport. The comments are hilarious! The way the English speak English is even weirder than you and I put together.

The longest stuff we are able to pull without a permit here is some states allow two 53' trailers. Tractors here have become lager and far more plush. I am amazed at the compact, short wheelbase stuff they have to drive in Europe. I get it with limited space they have to deal with. Here and in Australia we have miles and miles of open country. Long-nose conventional tractors are the norm here. It seems the only thing they have there are stubby cabovers with very tight single bunk sleepers.

[Tomterrific]

Back to engineering a strong box. My camper is one of the lightest weight possible as it is made from 5mm Revolution ply throughout. I recognized that the weak point on a box is the joint where the wall and ceiling/roof come together so I used a 1x2 along the edge for a greater glue joint. Around the curve I used blocks cut from 1x2 glued all around. I put 1x vertical battens around the windows and doors attached to the roof and floor. By having a strong skeleton a lightweight structure can be stronger than a heavy structure.

Tt

[MickinOz]

The longest stuff we are able to pull without a permit here is some states allow two 53' trailers.

I think the longest rig allowed on the main roads here is 53.5 metres. That's 175 feet.
There are all sorts of exemptions and special routes where things can be different.
But you aren't far off. Add 53 feet to 53 feet, include say 15 feet for the dolly, and say 25 feet for the prime mover, and you're looking at around 146 feet.
I reckon that a typical A trailer here is a 40 footer.

I think the only significant difference is that we run these things just about everywhere. The Victorians aren't so keen on them, not sure about the Tasmanians, but the rest of the country seems quite happy to pull as much freight as the prime mover can actually move.

Interesting thing I noticed in New Zealand. Apart from not seeing many semis anyway, I also realised the trailers don't have ring feeders on them. i.e. there is no tow hitch for a second trailer on.

[MickinOz]

Back to engineering a strong box. My camper is one of the lightest weight possible as it is made from 5mm Revolution ply throughout. I recognized that the weak point on a box is the joint where the wall and ceiling/roof come together so I used a 1x2 along the edge for a greater glue joint. Around the curve I used blocks cut from 1x2 glued all around. I put 1x vertical battens around the windows and doors attached to the roof and floor. By having a strong skeleton a lightweight structure can be stronger than a heavy structure.

Tt

I backed my joints up, too. Same reasons. My first build was with 17mm plywood for the walls. You have to be a good shot with the stapler to makes sure you don't spit a leg out the side. So I took 1 x 2's, which are actually 3/4 x 1 1/2 dressed all round, and glued and screwed them on. This gave me a 36mm wide gluing and stapling surface.

Then lined the inside, too.
She's 8 feet 10.6 inches long, and 5 feet 2.5 inches wide, and came in at 1111 pounds loaded with camping gear ready to hit the road.
And, as we say here in Oz, built like a brick outhouse.
So yes, I agree you can build strong but light if you use your head with the framing.