Mobile Home Standard I-Beam Shapes

[JohnnyB_]

Hello -

I have a a client that has retained me to design a foundation. The foundation is for a double-wide trailer. Each trailer has two I beams, four total. This is a used double wide so I cannot ask a manufacturer for beam specifications. The client states that the beam is 10 in deep and 2 3/4 in wide flanges. I cannot find a normal W beam shape based on aisc standards.

I need to get the section modulus for the I-beams so I can design the foundation at proper span intervals based on the residential loading criteria.

Does anyone have any advice on standard documentation for mobile home steel structural beams?

 

[jerseyshore]

Well first thing is did they only measure half the flange? That is very common when asking a non engineer to get a beam size. I always send a quick sketch ahead of time to eliminate any miscommunications for measurements.

Any mobile home beams I've seen appear to be standard sizes. Maybe some places use something other than W shapes or custom pieces.

 

[LittleInch]

This looks interesting - go to section 3285.303 about 3/4 the way in.

Looks to have what you need?

Federal Register :: Request Access

Also note the wind / hold down requirements....

 

[XR250]

They have always looked proprietary to me.
You could also just have him measure the flange and calculate it from there.

 

[phamENG]

They have always looked proprietary to me.

Same. Trailers are optimized for weight, so they're likely custom shapes. Best bet is for you to crawl under there and take the measurements yourself. You know what you need and what to look for. The owner does not.

 

[Eng16080]

It's probably either an M10x9 or M10x8. FYI, per AISC "I-beams" are comprised of the common W shapes as well as M, S, and HP shapes. It's either one of those or a custom shape if I had to guess. Can they tell you what the flange and web thicknesses are?

I would hope that it would be possible to get actual specs on these trailers through the client somehow. For something that is being dropped on your foundation, there shouldn't need to be any guessing in terms of what might show up on the truck. Nevermind, I missed the part about the trailers being used.

 

[ANE91]

There should be a data plate on the structure, somewhere. It’ll have the relevant information. It’s typically mounted (welded) to the chassis, but I’ve also seen stickers, and those come off. Owner may also have a laminated copy somewhere.

Regardless, you can calculate close-enough section properties by your own measurements.