Mobile home frame for short span bridge?

MMM · Nov 30, 2005

I can get burnt house trailer frame for cost of acet /ox to cut it into trailerable sections, provided I remove all of it.
Any TBNers seen these frames used for short span (10-15') bridges across creeks?

Dargo · Nov 30, 2005

Judging how all of the mobile home frames looked in the trees around here, I wouldn't want to use one. We had a really nasty tornado here that wiped out several dozen mobile homes, killing 24 people, and put mobile home parts everywhere. I had a close up view of plenty of the frames. They are flat not designed to support much at all. I suppose if all you wanted to drive across it was a lawn tractor, one might be okay. Otherwise, I'd skip it.

KubotainNH · Nov 30, 2005

It seems not all mobile homes are created equal. The one my mother lives in has a pair of pretty large I beams. I would think they would hold alot of weight for a 10 foot span.

RonR · Nov 30, 2005

They might have changed the process some, but years ago, one of my uncles welded on trailer frames. They ran HUGE rods at high heat on the tops of the beams to distort them UP at the ends. Then when the weight of the structure was on it, the trailer frame was level.

If they still do that, the bridge might normally sag.

Plus, I'm not sure what high heat (and they burn HOT) would do to maybe weaken the I beams??????
ron

MMM · Dec 1, 2005

I haven't crawled under this one, but frame looks to be 810" I-beam or C-channel from the road. I dont think the frame got too hot, as there are still some sections of subfloor left on one end. Still the bow you speak of complicates my idea of maybe welding one section atop another for added strength.
My rig is 8500lbs, so I won't tackle it unless I hear some success stories. (With the wide and varied audience TBN has, if no one has done it, or seen it, maybe I'd better not try)

RonR · Dec 1, 2005

Musta been asleep when I wrote the earlier post. If you wanted, since you will cut all the extranious stuff off anyway, you could put the top of the frame DOWN, that way the arch would be in the way you wanted it.

And if you can weld two sections together to double the thickness, it would add to the strength.

I'd want someone with stress background to put a blessing on it's strength before I built it and drove my 8500# unit over it. But I'm overly safety conscious--or at least I try to be.

Ron

BobReeves · Dec 1, 2005

If you measure the I beams can't you find out the load bearing spec for that I beam. Don't know just a thought.

crdnlplt · Dec 1, 2005

I have a buddy that made his flatbed trailer out of an old trailer frame that he cairries his Case 580 with. I would think with a little bracing that it would make a great bridge. Wonderful idea!

Darren · Dec 1, 2005

A family a few miles from my location had a bridge of about that length made from lightweight I beams. A flood moved it off the abutments. I looked at the steel afterwards and the thing that stood out was how thin the section was which meant that any rusting could compromise the strength.

I would try using the trailer frames with a couple of cautions. The length of the bridge should be no longer than what you posted. I'd use several beams. Maybe as many as four or six. Make sure beams are directly under the wheel path and tie all the beams together.

I've seen quite a few bridges that have used 3" pipe as a deck welded directly to the beams. That helps prevents the beams from falling over too.

SPIKER · Dec 1, 2005

I have one done this was now, it was not done by me but by the old guy who l bought it from. it spans some 20 feet but the creek is only about 8' wide & 3~4' down. it has telliphone poles lag bolted to the frame one on each side of the frame out side edge. the phone poles are pretty level across the top and then there are 2x6's screwed to the phone poles. i drive my tractor fel & hoe combo across it and have been pulling 2 cu yards+ of wet gravel across in my dump trailer with little sag. it has been washed down river one or two times and only needed dragged back into place. I'm not sure HOW MUCH SPAN there actually is it may be less than 10' ? weeds anbd gravel are built up around it a lot. water does not contact it but I imigine it is wet most of the time from moisture & rain...

My tractor hoe combo does make it creek a bit (probably 6K lbs as working weight is 4200 + FEL & Heavy Hoe) I think the HOE is dang near as much as the tractor so it MAY be more like 7000 across the bridge, and when I pull 2+ cu yards of wet sand/gravel that is dug out of the creek it don't give at all as the dump wheels are right ON the beams. where as the tractor tires are slightly inside each one as it is narrower...

Mark M