box section or I beam? ( and other questions ).

[ColJack]

before I start I'd like to preface the following by saying that this is just theoretical / for fun in my head and not an actual project or anything..

can you put a "join" in a load, on top of an I beam?

what I mean is imagine you have 2 shipping containers, say, and want to run beams under the long edges ( so you can ectend past the end and have a platform to stand on at the door end), can you "get away" with just 3 I beams? one under each outside edge and one under the point where the 2 meet?

the "load" in the center wouldn't be directly over the middle bit of the I beam, but would be just to either side of it, and would / should be even..

would a box section / beam be better since the vertical parts of the beam would be under the "loads"?

 

[^woody^]

The load would be uniformally distributed along the whole beam - ie the joint between the two containers would be irrelevant

You could do this with two beams running the length on the outer edges and no need for any beams running perpendicular between the two outer beams

 

[ColJack]

I could, but I really want ( in my head at least ) to have the beams extend past the containers and form a "balcony" at either end.. hence wanting to run them front to back..

like this..

View media item 49843

 

[^woody^]

Your OP said 2 containers and 3 beams

Now its 3 containers and how many beams and where?

 

[RonnyRaygun]

I could, but I really want ( in my head at least ) to have the beams extend past the containers and form a "balcony" at either end.. hence wanting to run them front to back..

like this..

View media item 49843

I think Woody, (and I) was thinking that the containers would be end to end. Looking at the pic above, you mean they would be side to side?

Theoretically, three beams would be enough. The middle beam would have to be bigger as it is taking twice the load of the outer ones.

The flanges of the middle beam would have to be designed/checked for bending and deflection as the you essentially have two separate loads either side of the web, causing the flange to want to bend.

So you are correct in assuming that a box section may be better. It eliminates the need to check the flange for capacity, but furthermore, an unrestrained I beam will suffer from lateral torsional buckling which the box section doesn't. This may allow the box section to be lighter than a suitable I beam.

 

[ColJack]

Your OP said 2 containers and 3 beams

Now its 3 containers and how many beams and where?

Thanks for the help so far..

I did say it's theoretical , and the number of beams and boxes shouldn't make a difference to the general theory, it's the joint between any 2 boxes over the one beam that I was trying to describe..

failing that, the containers are self supporting when stacked so what would be the other options for adding a walkway and / or balcony at the ends of the containers?

 

[^woody^]

The load would be uniformally distributed along the whole beam - ie the joint between the two containers would be irrelevant

 

[ColJack]

I think Woody, (and I) was thinking that the containers would be end to end. Looking at the pic above, you mean they would be side to side?

ah yes, reading it back now I can see I wasn't very clear..
I should have said side by side and I meant 3 beams running in parellel, not in a H configuration ( which from your post I take it is how you read it?)

I'm designing ( or rather re-creating a site I once worked on ) some flats / challets made with modular blocks that would be manufactured off site and craned into place..

each "flat" consists of 3 x 20 foot shipping containers converted into a 1 bed flat with loung, kitchen and bathroom..
they would need a walkway along one side at least to access the front doors ( whether this is glazed and enclosed or open as is seen at such places as butlins etc.. ).