steel strength vs size ?

[hazmat]

<font color="blue"> Yeah but as your size increases, so does "c" in the numerator. So to compare two candidates in bending, compare bh^3 rather than bh^4.
</font>

Man the teacher busted us /forums/images/graemlins/shocked.gif

Thanks for catching our sloppy engineering. Hard to think straight when you've got tractoring on the brain /forums/images/graemlins/tongue.gif

Nice suggestion RE the angle, might give a larger "step" for the drivers to land on.

 

[hockeyhead]

If I understand this right, this is a "free standing" 30" ladder clamped to lip of a lowboy . first any of the materials described here will easily surpass your requirements. As far as the clamping to trailer that 3 pieces of welded flat stock and a couple of bolts appears to me to be your weak point. flexing, as a 350lb man climbs up and down. that same Ryerson catalog that spec. sheet came from has a large selection of "C" channel and such. Or a fab shop could brake something up.
My other thought was steel get pretty slippery when wet.
In rainy or winter conditions, slipping on a 1",or 1.5", square tubing ladder is going to hurt. round stock rungs would inprove this or brake up some 1/8 diamond plate for rungs, if employees or co-workers are going to use this you might want to look at some kind of traction control , just my 2 cents worth good luck with ladder

 

[trailertrash]

Even tho I've been on here (tbn) for a while it still amazes me with the amount of available info that is freely offered by the professional members and those with experience in what ever area that it is needed. Anyway thanks for everything and I'll check back with updates as soon as possible.

 

[rlw]

<font color="blue"> </font> "Yeah but as your size increases, so does "c" in the numerator. So to compare two candidates in bending, compare bh^3 rather than bh^4." <font color="blue"> </font>

<font color="black"> </font> Oops, my mistake. However, I think you meant to say compare c/I, where c is b/2. <font color="black"> </font>

Good point on the angle iron - I agree. I rarely use square tubing, almost always angle or C to help on weight.

 

[jmc]

"Do a weight calculation prior to fabrication. The self weight of your project can get pretty heavy in a hurry."

You'd be suprised at how many times I have relearned
this tip!

As far as bending, I subscribe to RonR's "Fat Guy Theory". There is probably some weight to be saved. The bigger risk is a defective weld. The steel will bend but probably not snap like a bad weld could.

What about using aluminum?

John

 

[jmc]

rlw,

"However, I think you meant to say compare c/I, where c is b/2"

Yes! Thankyou.

John

 

[gsxr1100]

hazmat & jmc:

Okay they beat me to it! Weird I did not think anyone remebered there stuff from materials. Comes in handy!

 

[TheKid]

I have to agree with Ron when he said </font><font color="blue" class="small">( I would more concerned with how it attached to the trailer so that doesn't fail or come undone and cause the ladder to crash down. )</font> I had a couple of ideas for making the mount stronger. Add an aditional brace that goes below your clamps and rests on the side of the trailer. Use a mounting system that slides over the sides of the trailer to lock it in place. I modified your original drawing to show you what I mean.

 

[RonR]

The big head

You guys keep agreeing with me I'm liable to get the big head!

Take care,
Ron

 

[keeney]

Do the trailers have stake pockets? If so, your mount could be a piece of rectangular section that slides down into one or two of those.