I want to wall off the center section of my polebarn so I won't have as much to heat this winter. I plan on putting two 10' by 10' doorways in the interior walls so I can drive straight thru if need be. I was wondering what size I-beam I would need to span one of the doorways so I could lift up a two ton max load? Here's a picture of my barn.
What picture? [img]/forums/images/icons/confused.gif[/img]
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I'll retry the attachment
I saw a gantry crane in Northern's catalog. 12ft total length. Probably about 10' between the columns. Was a 8" x 4" beam but no idea how many lbs/ft the beam is. Maybe you could talk with a steel supplier. This is a simple calculation as far as engineering goes. I will dig out a strength of materials book I have and see if it has anything. You will also need to design something to hold up the ends of your beam plus the live load. What about keeping it from tipping over either to the side or in length? I don't know what safety factor you would want but I would look for something between 1.5 to 3 times.
Sorry about the rambling I just kept thinking of things while I was typing.
Yep, I-beams are like apples and oranges. I talked to a millwright at Pontiac Motors, where I used to work, and it depends on the thickness of the beam material and the size of the beam. He said a 8" by 6" H-beam, 1/4" thick, should work. But to make sure the support is solid. Thanks.
Attached are some beam dimensions and some calculations that you can use to size the beam. The example uses an 8" beam to determine the minimum "I" value. Then look at the beam tables and select a 8" beam with an I value greater than the calculated value. Also want to look at deflection of the beam under load. Use the actual "I" value from the tables in this calculation.
This is an iterative process to find a strong enough beam that isn't going to deflect too much.
These calcs don't include the weight of the beam, but will work fine.
Sorry I won't be able to reply to any questions on these calcs as I am leaving town for 2 weeks in a couple hours. I'll check back then.
Thanks..
The Northern Gantry was for 2,000 lbs not 2 tons [img]/forums/images/icons/blush.gif[/img] . My mistake might want a bigger beam as suggested in the calculations by rlw.
rlw, What would be an acceptable deflection? 1/240th, 1/360th? Would that depend on the type of column connection (fixed or rotating/sliding?) how much bending/deflection the column would withstand if a fixed connection? Length of column would also play into how much bending the column could withstand.
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