|
|
Of the 3 - 3x5 #7.7 I Beam / 4x6 #9 H Beam / 4x1/4 Square Tube - which has the least amount of sag over 30 feet if sitting only supported by a 4" pad on each end? No nuns, puppies, or children will be asked to stand or jump in the middle of the beam until failure for this experiment.
Reply:If this a test? - I'll take a guess. If this is a question, don't listen to me.The 3x5 7.7 I beam (in the proper orientation)edit; uh oh, I'm second guessing my self on the 4X4.Last edited by rustyiron; 10-14-2014 at 07:57 PM.
Reply:The 4x6 9lb by a big margin.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Originally Posted by PipelinerOf the 3 - 3x5 #7.7 I Beam / 4x6 #9 H Beam / 4x1/4 Square Tube - which has the least amount of sag over 30 feet if sitting only supported by a 4" pad on each end?
Reply:Originally Posted by irish fixitThe 4x6 9lb by a big margin.
Reply:Wide flanges almost always out perform similar sized square tube in bending, since the material is use more efficiently in a wide flange as more of it's material is concentrated farther from the neutral axis of the member. Wide flanges, typically taller members out perform shorter members in bending, even if the shorter member is heavier. It takes a lot of extra mass at the flanges to off set an extra inch or so in distance from the neutral axis of the beam. ( center in bending).No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I wasn't expecting this many great responses so soon confirming what I believed was the correct answer. Thanks everyone - stick a fork in it, we're done here.
Reply:PipelinerIs this a 'Beer Bet' - or are you actually building something?Opus
Reply:Most definitely a variation of a Beer Bet.
Reply:PipelinerMuscling up on hypotheticals . . .It good to know that my kind of people are out there.Opus
Reply:Hi everyone, I always use this before I buy any material (even salvage metal).Use this link to calculate the moment of interia. Deflection is inversely proportional.http://civilengineer.webinfolist.com/str/micalci.phphttp://civilengineer.webinfolist.com/str/micalcrh.phpI went through an explanation of how to input and interpret the moment of inertia vs weight in this post below about ramp size. Inputting the values is a little tricky because of the images and descriptions not matching perfectly, but you can follow the examples in the post. http://weldingweb.com/vbb/showthread.php...-material-sizeIf you were doing a true structural calculation for a 30ft span you'd need to include a distributed load of the weight of the beam itself (q in the link provided by forhire).TimPS. I'd do most anything for beer....
Reply:When I built my bridge crane, I had a PE friend check over my design. He said for the span, an S-shape was going to be too tall, and just kill my head room. He suggested I use an H-beam, rip an S-shape, and skip weld 6 on 12 the ripped S-shape to the bottom of the H-beam. Attached ImagesDont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400 |
|
发表于 2021-8-31 22:19:59