2" x 2" x.125 ASTM A500 Grade B tubing
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Posted by: rogera ® 04/09/2004, 13:15:22 Author Profile Mail author Edit

Posted this back in February and didn't get a response so am trying again. I need to mount a ceiling mount handicap lift in my motorhome.  The weight must be born by the sidewalls.  I would like to use 2"x2"x .125 thick steel tubing from wall to wall to mount the track for the lift.  The span is  96" and the weight point would be slightly off center.  I am not capable of figuring the load ability of this tubing and would appreciate some help.  If this tubing isn't strong enough how big would I have to go?  Thanks, Roger

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Re: 2" x 2" x.125 ASTM A500 Grade B tubing
Re: 2" x 2" x.125 ASTM A500 Grade B tubing -- rogera	Post Reply	Top of thread	Forum

Posted by: Cragyon ® 04/12/2004, 07:16:23 Author Profile Mail author Edit

Roger, Visit the following page https://www.engineersedge.com/beam_calc_menu.shtml and determine which beam deflection calculator is most representative of  your case.  This will probably be "supported on both ends and loaded at any point You need the following engineering information (the rest is self explaining): Modulus of Elasticity of your beam Moment on inertia of your beam Open the calculator and input the information,  then calculate and see if the deflection is rely low, like less then .1 inches. Also look at the stress, hopefully it is less than ~ 200.  If your defelction is high, then use a heavier beam (higher moment of inertia) untill your deflection and stress numbers are low enough.   Good luck!

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Re: 2" x 2" x.125 ASTM A500 Grade B tubing
Re: 2" x 2" x.125 ASTM A500 Grade B tubing -- rogera	Post Reply	Top of thread	Forum

Posted by: devitg ® 04/10/2004, 19:26:39 Author Profile Mail author Edit

Posted this back in February and didn't get a response so am trying again. Hi Rogera , please let me do some consideration. You need to be more especific on your question ,if not,  you will get  just the same amount you give,   as in Feb you give nothing , you get nothing . Just for not happen the same  for this case the most valuable data is. Load to be lift Angle to both axis of the beam , maybe it will be the same of X axis in this case , guessing the load is just down the beam. Distance from one end of the beam. That's is the data you shall give . But as my experience the best suited beam will be a Round tubing , because it's independient of the angle you load it. So please give us the requiered data    Hope it help .

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Re: 2" x 2" x.125 ASTM A500 Grade B tubing
Re: 2" x 2" x.125 ASTM A500 Grade B tubing -- rogera	Post Reply	Top of thread	Forum

Posted by: rkazanjy ® 04/10/2004, 15:16:55 Author Profile Mail author Edit

Roger- I just registered on Engineer's Edge Design & Engineering Forum. The guys in the newsgroup   sci.engr.mech  will probably be more responsive. To increase your chances of getting useful replies, provide lots of info supporting your question.  I do not fully understand what you are proposing.  Does the lift you are trying to install have a website?  I assume the lift some how runs out of the motor home (ie cantilevers off a ceiling support track and goes out thru a door?) regards Bob

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Re: 2" x 2" x.125 ASTM A500 Grade B tubing
Re: Re: 2" x 2" x.125 ASTM A500 Grade B tubing -- rkazanjy	Post Reply	Top of thread	Forum

Posted by: rogera ® 04/12/2004, 10:26:10 Author Profile Mail author Edit

Bob, I will try to be a bit more clear about what I am proposing.  The lift is a Barrier Free "Glide Free". The steel tubing will be bolted to the framework of the motorhome walls at 4 foot intervals.  The track system will then be mounted to the tubing .The weight  to be lifted is 300# and the lift point will be 36" from one end of the tubing.  The weight includes the weight of the lift and the track.  The lift is 24v powered via two 12v self contained rechargeable batteries. I can't use a calculator because I don't understand the terms that they require. If you need any further information I would be happy to supply it. Thanks, Roger   Edit reason (no product links allowed) Modified by Administrator at Mon, Apr 12, 2004, 10:42:25

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Re: 2" x 2" x.125 ASTM A500 Grade B tubing
Re: Re: 2" x 2" x.125 ASTM A500 Grade B tubing -- rogera	Post Reply	Top of thread	Forum

Posted by: rkazanjy ® 04/13/2004, 00:22:10 Author Profile Mail author Edit

Ask the mfr but it looks like the system track can be mounted directly to the motorhome ceiling. Is the track only going to be insdie the motorhome?

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Re: 2" x 2" x.125 ASTM A500 Grade B tubing
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Posted by: rogera ® 04/13/2004, 12:24:21 Author Profile Mail author Edit

The mfg. has stated that the load MUST be carried by the sidewalls.  The lift will only be used in the MH. Roger

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Re: 2" x 2" x.125 ASTM A500 Grade B tubing
Re: Re: 2" x 2" x.125 ASTM A500 Grade B tubing -- rogera	Post Reply	Top of thread	Forum

Posted by: jcmcgraw ® 05/25/2004, 16:25:54 Author Profile Mail author Edit

Roger,  the following information is on Hollow Structural Steel tubing.  Maybe someone on the site can run some calcs for you.  This info is from the Steel Tube Institute of North America. 2x2x1/8 weight/foot: 3.05 lbs  Wall thickness: 0.116 in  Cross sectional area: .84 in sq.  I = .486 in^4. S = .486 in^3.  r = .761 in.  Z = .584 in^3.  Torsional Stiffness Constant (J) = .796 in^4. Torsional Shear Constant (C) = .817 in^3.  Surface area per foot = .63 ft^2 Hope this will help.  Maybe someone can plug these into the calculators, or you might be able to use them yourself.  The nomenclature is standard through out all the design of structures. JC

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