Max load Guestimate?

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Ok, so I need to make ramps for my trailer, and really like the design of these ramps.http://weldingweb.com/vbb/showthread.php...=Trailer+RampsCan anyone give me a guess on the maximum load based on the materials used in these ramps? Hoping someone out there has a program they can just throw the specs in to get max load.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:[ame]http://www.youtube.com/watch?v=CQFEY9RIRJA[/ame]There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:Did you try PM-ing Planet X or Franz(from they linked thread) to see if they had a guesstimate?What is the max weight you anticipate loading with your ramps?Last edited by Bistineau; 05-08-2012 at 08:45 AM.
Reply:not a load estimate.  What are you asking for a point load in the middle of an 8 foot span span?  Something like an ag tractor will not even have one axle on it when the other axle is in the middle.  I am guessing this is kind of quad or side by side or atv range just by the weight vs length.I don't like that design.  I was looking at sort of the same idea for a paving machine, obviously much heavier, and discussing options as I was planning on making ramps myself.  He had used channel for the sides and put the angles between them.  I forgot which way the side ones went and the ones in the middle can be set to shed water or have more gripping and catch water.  You can tune how much higher the edges are to your liking..  Similar could be done with rectangualr tube allowing a higher section piece in the matrials list.  You can easily put a wood block (at any location) under the span when done that way..  There are way less sharp edges to scrape your body.  Something to keep the rear of the trailer from going down is generally incorporated into the overall design.
Reply:Using an AISC beam formula spreadsheet, and ignoring the flatbar / truss, it came to approximately a 1000 pound load per ramp (using a point load in the center). Once I made an approximation to account for the flatbar truss, It jumped to nearly 4000 pounds per ramp.JasonXMT 350 MPA Dynasty 280DXSuitcase 8RC / OptimaSpoolmatic 30AThermco Ar / C02 mixerAssorted O/A gear
Reply:That must be a max load not a safe working load.  If your projects go like mine welding all those angles to the rectangular tube and much less weld on the bottom the pieces will no longer be straight.  You might also look at that place the curved flat bar attaches to the ramp and the round bar and it's attachment points.
Reply:The numbers I used were with a safety factor of 1.2 rounded down to an easy to remember number. Typically people do not know the exact weight of each axle, so its all approximate anyway. The other reason I am not overly concerned is because of the failure mode. The ramp will slowly fold up as you overload it. No personal injury, no damage to equipment (besides the ramp).JasonXMT 350 MPA Dynasty 280DXSuitcase 8RC / OptimaSpoolmatic 30AThermco Ar / C02 mixerAssorted O/A gear
Reply:And its impossible even for engineers to predict how a piece will warp and the resulting capacity when a backyard fabricator builds it. The OP will have to determine his own safety factor he is comfortable with. It doesn't hurt to err on the side of safety.XMT 350 MPA Dynasty 280DXSuitcase 8RC / OptimaSpoolmatic 30AThermco Ar / C02 mixerAssorted O/A gear
Reply:the most each ramp would ever hold would be approximately 2800 lbs. Case Skid steer. The wheel base is approximately 5' so both axles will be on the ramp at one time but the full weight will never be in the center of the ramp. Primary use will be quads and or SxS.  but the idea is to keep the ramps longer than I plan on keeping this perticular trailer.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:If its possible to work into the design with the equipent you have, I would suggest a camber to the material (ie by rolling, or heating or bending or welding all your cross supports underneath with a lot of heat) then a truss like the other ramp. Could use cf round bar or flat depending on your preference and whats at hand. Keep in mind all the strenght of this is in the depth of the truss, so a heavy square tube is not necessary, I would think a properly setup 1 x 3 x .120 wall or 1 x 4 x.120 with a camber and a lower chord of 5/8 or 3/4 bar stock would be immensely strong. If you give us some load ideas I would play with the figures in SW and see how it works out for you. "Anybody can talk $h!t behind a monitor, I let the quality of my work speak for itself"Lincoln Square Wave 255 and 355 Tig Lincoln 255 Power-Mig w/ spool gun Koike 5 x 10 CNC plasma Hyd-Mech DM-10 bandsaw Ineco QB-76 NC tube bender
Reply:Noted above specs while posting....did not see an overall length for them though? "Anybody can talk $h!t behind a monitor, I let the quality of my work speak for itself"Lincoln Square Wave 255 and 355 Tig Lincoln 255 Power-Mig w/ spool gun Koike 5 x 10 CNC plasma Hyd-Mech DM-10 bandsaw Ineco QB-76 NC tube bender
Reply:length is 8'If I can handle the load with 1"x2" .12" wall rec It'd save me $50 a stick. and with weight being a consideration I'd like to keep the "bowstring" to 1/8" or 1/4".I don't have anything to arch the long pieces, which is why I like the design in the link. I'm trying to keep the weight down as much as possible. And if I can't hold the skid steer with these ramps thats fine. I can figure out either a different trailer to move it, or different ramps.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:Do you have a hydraulic press? I have had good luck with putting gentle arches into tubing before we bought a roll bender...just mark out evenly spaced increments on the tube, touch the tube with the press and count the strokes, repeat as necessary. Use a wood block or something to avoid kinking the tubing or you will have a failure point. In an 8' ramp you wouldnt need much of an arch and I think it would be easily accomplished with a small shop press. I do think the bowstring would be better served by being maybe 3/16 or 1/4 by 1" flat if you want to forgo the round bar. I wouldnt recomend this for a skid steer without much further testing, but a quad or lawn tractor etc etc I would have no issue at all with. "Anybody can talk $h!t behind a monitor, I let the quality of my work speak for itself"Lincoln Square Wave 255 and 355 Tig Lincoln 255 Power-Mig w/ spool gun Koike 5 x 10 CNC plasma Hyd-Mech DM-10 bandsaw Ineco QB-76 NC tube bender
Reply:Hey Thor, Ive used ramps similar to the ones youve shown to load a large Bobcat skidsteer but your original question,"guess the maximum load...". Ive wondered how they calculate that myself. Anyway, I found these calcs in the LINCOLN ELECTRIC book 13th   The PROCEDURE HANDBOOK Of Arc Welding on page 2.1-27 and 2.1-28. It talks about moment of inertia and deflection. I still dont get it. It seems like just build it, if it breaks, analysis, modify and impove it until it works.
Reply:Originally Posted by InsanerideHey Thor, Ive used ramps similar to the ones youve shown to load a large Bobcat skidsteer but your original question,"guess the maximum load...". Ive wondered how they calculate that myself. Anyway, I found these calcs in the LINCOLN ELECTRIC book 13th   The PROCEDURE HANDBOOK Of Arc Welding on page 2.1-27 and 2.1-28. It talks about moment of inertia and deflection. I still dont get it. It seems like just build it, if it breaks, analysis, modify and impove it until it works.
Reply:The length is 72  inches, 12 inch wide, 3 inch c chanell stringers, with 2 inch angle rungs. The rungs are aprox 8 inch on center 9 inch between the stringers for these ramps. The trailer they came with  was rated for 10,000 Attached Images
Reply:My ramps are made of 2x2x.250, three tubes per ramp, and are about 5' long, and plated with 1/4" tread plate. I have had 7,000 pounds on them (3500 each amp) with no trouble at all. Those ramps have a strongback on them, which takes them out of the arena of simple math. You can calculate your own hollow section simple deflection easily with an online calculator.  http://www.calculatoredge.com/civil%...eam.htm#hollow
Reply:I've got an engineer buddy of mine getting me exact numbers on the ones I want to build. I will keep you guys posted on what I find out for solid numbers. though because I'm not paying him, he said it would take him a while.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:Originally Posted by BistineauDid you try PM-ing Planet X or Franz(from they linked thread) to see if they had a guesstimate?What is the max weight you anticipate loading with your ramps?
Reply:Originally Posted by Old FartThat has got to be the funniest thing I've seen on this site.I take it you didn't notice how many of those men are listed as "guest".  Evidently you weren't around here when the former ownership placed Joey the Magnificent in as Moderator and called the men who built this site from nothing the GARBAGE GANG.Long way back to 2005 for sure.  Franz is still kicking in spite of some people's wishes, but he damn well don't set foot here.
Reply:I would sniff around and try to identify a set of commercial ramps that are guaranteed to do the job from a reputable supplier that has been in business for a very long time.Then home build something along very similar lines.................Cheers,  Tony._________________________________Transmig 310 + Argoshield LightOxy acetyleneOxy propanePrehistoric stick welder_________________________________
Reply:Originally Posted by WarpspeedI would sniff around and try to identify a set of commercial ramps that are guaranteed to do the job from a reputable supplier that has been in business for a very long time.Then home build something along very similar lines.................
Reply:Originally Posted by ThorsHammerI've been looking for something I could home build, but most of the commercial ramps I've been able to find have been modular pressed sheet metal units with center supports, and limited framing. Or they've been aluminium, and I'm not comfortable enough with aluminium to take on a ramp build. not to mention the increased cost of using ali.
Reply:Real operators don't need ramps to load the skid steer![ame]www.youtube.com/watch?v=xhUUNftcmpU[/ame].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:Originally Posted by ThorsHammerMost of the commercial ramps I've been able to find have been modular pressed sheet metal units with center supports, and limited framing.My ramps are lighter than those and I can load a backhoe.  Just reverse engineer it, don't try to calculate it. There are plenty out there you can take a peek at.  You can calculate all day long, but that won't help you when someone goes a little fast, or slams the brakes on while loading.  Cheat a little, copying is the best form of flattery.
Reply:Originally Posted by walkerMy ramps are made of 2x2x.250, three tubes per ramp, and are about 5' long, and plated with 1/4" tread plate. I have had 7,000 pounds on them (3500 each amp) with no trouble at all. Those ramps have a strongback on them, which takes them out of the arena of simple math. You can calculate your own hollow section simple deflection easily with an online calculator.  http://www.calculatoredge.com/civil%...eam.htm#hollow
Reply:Originally Posted by blackbartMy ramps are lighter than those and I can load a backhoe.  Just reverse engineer it, don't try to calculate it. There are plenty out there you can take a peek at.  You can calculate all day long, but that won't help you when someone goes a little fast, or slams the brakes on while loading.  Cheat a little, copying is the best form of flattery.