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Hi. I want to learn some better way to calculate steel beams, posts, trusses for projects. I am working on a design now to lift 5K + pounds of weight and I am trying to design in a way that is lightweight, so this question popped up again, how do I come up with the layout style (Big beam vs Truss vs?) and what shape and size tubing do I use? While it is nice to have folks help me by solving it, I would really like to be able to make some headway myself. I know there are a huge amount of variables, but surely there must be some basic design parameters that will keep me from using 1/4" wall when 14 gauge will work? I have welded a few dozen projects together over the last few years. I tend to throw a heavy piece of steel that "ought to work" and this usually equates "P" for plenty, or really over engineering, or guessineering. While I expect to add some extra steel to a structural problem, I hate the fact that I am just faking it. Can anyone point me in the right direction for a beginners guide to steel math that would help me solve my current problem and aid me in the future?I was not sure if this was the correct forum for this sort of question, so if it is not, please point me in the right direction.
Thank you.-Mike
Reply:Sounds more like a question for someone with a mechanical engineering background. I would like to know the answers to your question as this applies to many aspects of fabrication. Hope some one chimes in with a better answer than me :/edit: there is probably some literature out there that provides this information but I have no idea of where to find it.Lincoln, ESAB, Thermal Dynamics, Victor, Miller, Dewalt, Makita, Kalamzoo. Hand tools, power tools, welding and cutting tools.
Reply:There are calculators available online but you need to think about safety factors, unexpected loading etc.,etc. Have fun.http://www.atc-mechanical.com/calcul...al-properties/https://www.amesweb.info/StructuralB...lculators.aspxhttp://www.geocities.ws/richgetze/---Meltedmetal
Reply:i don't know, but i'd think that the state would want a lic'd structural steel contractor to kinda know stuff like that, which would make me guess, that if you found a used c-51 trade book somewhere, it might have what u want
Reply:Thank you gents. I will look into those links and ideas. -Mike
Reply:And get yourself a copy of 'Machinery's Handbook' as it has tons of invaluable information on mechanics and strength of materials among hundreds of other subjects
Reply:You'll get better info from an old school iron worker
Reply:nice collection ronsil. having one of them is worth its weight in gold
Reply:Yes, they are extremely handy
I have just about every edition printed
must be a collection sickness!!!!
Reply:I have a machinery handbook from 1989, I don't remember what edition, but they are awesome. I just don't see the need for every edition, unless for collectors value.IMPEACH BIDEN!NRA LIFE MEMBERUNITWELD 175 AMP 3 IN1 DCMIDSTATES 300 AMP AC MACHINEGOD HELP AMERICA!Freedom is never more than one generation away from extinction.We didnt pass it to our children in the bloodstream".RONALD REAGAN
Reply:My dad was a licensed professional engineer who taught me that engineers didn't have to know crap, only where to find the answer. And while it would be nice to learn where to find the answer, unless you're a licensed professional engineer you answer is only good for you. Anyone getting hurt by your design would own you.
Reply:
Originally Posted by CAVEMANN
I have a machinery handbook from 1989, I don't remember what edition, but they are awesome. I just don't see the need for every edition, unless for collectors value.
Reply:Thanks so much for those links. The second link: https://www.amesweb.info/StructuralB...lculators.aspxwas very helpful too me. I think i can use this to get smart on some terms and let the calculator do the math, then try to get an explanation, intepretation of the answer. Once I get this down, I will look into some truss design calculators - regular, then triangular and square. I also found a PDF copy of the machinery handbook. Wow, that is a lot of pages. If you know that book cover-to-cover, you have a wee bit o knowledge, especially if you have experience using it. Iron workers work off blueprints and when they build their own stuff, they throw steel at problems, from experience in some cases, but typically devoid of science. My good friend was an iron worker in California and Nashville for 35 years. He ran a company of 150 iron workers, and he does help me on projects, but it is "P" for plenty and way over engineered. Now, if I am constructing a steel building, he will have his preferred practices for assembly construction, but it would be a huge waste for me to seek his help on my goal of the minimum design for lightweight log lifting device as he would be without the experience in this specific problem and have to throw steel at it... way over engineer it, He did get a smile out of your comment though.
I don't think a licenced engineer factors in here, as the answer is valid for anything I build, unless I was needing a state stamp of approval to build my device. I am not anywhere near that need for my projects. A licensed engineer can get sued if their stuff fails too. The trailer manufacturer who does not need a licenced engineer is in the same boat if he has an an engineer or not. Some welders need to be licenced, so if you need a licenced welder, you need one. if not, you don't. The engineer, weather licensed or not, will know how to do the math I desire to do. However, if he is licensed, he will likely exceed industry safety margins in his design by 10% or more, so he protects his licence. Cost "him" nothing to add more to the design and helos him protect that licence. If I can figure out his math and do it myself, I am good to go.... unless I want to design a building in a code enforcement area, or some other thing that requires a licenced structural engineer approval, such as a bridge, etc..Thank you all for chiming in. -Mike
Reply:A friend used to tell people that I memorized the entire WORLD BOOK ENCYCLOPEDIA, LOL.IMPEACH BIDEN!NRA LIFE MEMBERUNITWELD 175 AMP 3 IN1 DCMIDSTATES 300 AMP AC MACHINEGOD HELP AMERICA!Freedom is never more than one generation away from extinction.We didnt pass it to our children in the bloodstream".RONALD REAGAN
Reply:I look at big books like those listed above and the Lincoln Electric welding books and my head starts to hurt. Way too much information to soak in. I like the KISS method
How about a youtube video showing how it's done using the calculator above. I can dig on that.Lincoln, ESAB, Thermal Dynamics, Victor, Miller, Dewalt, Makita, Kalamzoo. Hand tools, power tools, welding and cutting tools.
Reply:
Originally Posted by N2 Welding
I look at big books like those listed above and the Lincoln Electric welding books and my head starts to hurt. Way too much information to soak in. I like the KISS method
How about a youtube video showing how it's done using the calculator above. I can dig on that.
Reply:What you want to accomplish is a lifetimes worth of work.
Reply:Unfortunately everything has consequences. The well built awesome 5000# hoist you build today, gets sold to somebody else in the future (say after you pass on...) . And that somebody tries to lift too much weight. And stuff happens. Accidents are never good. I personally know of two terrible accidents, largely related to engineering issues while I was in the military. (One was a tow rope which broke under exceptional load related to the collapse of a sand ramp during a river crossing training, the other a split ring truck tire not in a proper safety cage.) Permanent, life debilitating accidents. You don't want to be the person who possibly creates an adverse situation. Oh, and I am a Licensed Professional Engineer. I know how to calculate moment, shear, stress, predict deflection, calculate center of inertia for different cross shapes. But after reading the details of such events as the Hyatt Regency Walkway Failure or other steel strength design issues, I don't even want to take jobs like that. Heck, I'm thinking of building something as stupid as a super low angle drive on oil change ramp for myself, wondering if the risk is worth it.. So I'll build a set of ramps, but you can be sure it will be over designed, and well marked with max load. But no, I won't share the design here in public forum. That sets me up for risk. Color me nervous.
Reply:So Zipit, We hire engineers to do specifically what you seem to be adverse to doing. I never thought negligible risk projects needed an engineer. No doubt I've seen poorly engineered structures fail but many of the failures I've seen result from lack of oversight on the project and poor quality work and materials or outright cheating the consumer by installing sub par material or leaving out components entirely. So what kind of project are you comfortable engineering?For your oil change ramps, go look at one of those tipping ramp affairs the car dealers use to elevate cars on display in their lots and beef up the design if your manufacturing skills are up to it.---Meltedmetal
Reply:Normally you are right. But anything that may have a human being on it, in it, or under it, or heck even next to it, ever, requires some thought. On it (Hyatt Regency Walkway collapse)In it (Elevator)Under It (Florida Intl University Pedestrian Bridge Collapse)Next to it (oops. Bad welds caused this failure. But why didn't engineering / management call out requirements clearly and inspect to standards? ) but you get the idea.
Originally Posted by Meltedmetal
So Zipit, ... I never thought negligible risk projects needed an engineer. ... So what kind of project are you comfortable engineering?
Reply:Over the years I have seen many an engineered project fail in actual practice. Now you can say well no one ever thought they were going to use it in mud, or that no one thought the plywood they were rolling it on would have given way like that. Or the cement that was supporting it would have cracked. But in reality that is just the stuff you have to think about. I was just in a newly built laundromat, instead of a six-inch pour for a floor, they got away with a four-inch pour. I was mounting a change machine base I made, to the floor for a friend, and I hit the dirt at 3 1/2 inches twice, and 4 inches two other times. The floor had already started to sink, crack and become unlevel. Whenever anything moves, it has to be overbuilt, for reasons like the above. You have to be a pessimist and expect the worst; most young people in college are not up to thinking like that; they want happy thoughts. You also have to have in the shop, and in the field experience working with the tools and equipment that you wish to build. Otherwise, do not bother. Years ago I built arched gusset "A" frames to lift boats in the warehouse. We used them for a year with no issues and even misused them with no issues, then someone either too lazy or just not too savvy locked the wheels on the "A" frame straight, as he was misusing them to move a boat with a forklift. The legs of the "A" frame tracked apart and set the ocean racer, on the ground as the "A" frame plastically deformed. No damage to the boat, but the "A" frame was toast. It could have been worse. You cannot expect common sense. And at some point, you have to agree to kill someone that is lacking common sense, to an extreme degree.The reason we put locking wheels on the "A" frame was so we could aim the "A" frame unloaded at the place we wanted it to end up and then lock the wheels, we could push it from only one side of the "A" frame and move it to where we wanted it to go. We had warned all involved never to lock all four wheels under a load. But you know how good advice falls on deaf ears.If I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.
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Originally Posted by ronsii
And get yourself a copy of 'Machinery's Handbook' as it has tons of invaluable information on mechanics and strength of materials among hundreds of other subjects
Reply:LOL, yep.... hard to get much done right though when your mouth is watering and you keep thinking about food...
Reply:In your original post( left pic) I use similar when I build but with 8" round, filled with cement and attached top and bottom to a concrete tie-beam and floor. The I-beam is for the rolling chain hoist....or electric. The upper is needed if it's roof, bracket arm to concrete wall, or other.Gusset that 90 with 3/8 plus.Talk with the 'engineers' at a steel supplier. They've seen it all.
Reply:If a person wants to learn a good source is the Design of Weldments which is a Lincoln book available from their knowledge site. The series of books by Blodgett is excellent. Apparenlty Blodgett was an engineer or Lincoln well into his nineties.https://www.jflf.org/SearchResults.asp?Cat=81The Lincoln foundation is a non profit that was set up many decades ago and the prices are fair. They are not out to gouge you.
Originally Posted by henry42
My dad was a licensed professional engineer who taught me that engineers didn't have to know crap, only where to find the answer. And while it would be nice to learn where to find the answer, unless you're a licensed professional engineer you answer is only good for you. Anyone getting hurt by your design would own you.
Reply:You really need to aprentice with your father from when you are about two years old. And then volunteer for any interesting task that your neighbors, family, or friends of the family have for you. My little guy was laying shingles on the roof with me when he was two years old. Sincerely, William McCormickIf I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.
Reply:Some of the most educational things in my life related to stress and deflection came from watching tools that I thought were so hard and inflexible, bend like rubber when used as a lever. Or when the tool got stuck between two rocks, and it flexed easily. Getting my fingers caught under a very light davit arm near the mounting base was very educational about cranes. The increasing force needed to lift a boom, the closer you are to the pivot point of the boom. These are essential things to understanding structural strength. Sincerely, William McCormickIf I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.
Reply:
Originally Posted by Oscar
Unless it is a new structure. Not everything dreamt up by the human mind has been evalutated from a mechanical engineering standpoint. That's why mechanical engineers need to solve complex problems on Solidworks or some other kind of professional FEA software. Also, (with all due respect to your Father) it's BS that a mechanical engineer doesn't have know crap. I had lots of ME major'ing friends when I was in college. Guess what - they were taking Calculus-III and Differential Equations just like I was. They had to apply Linear Algebra to solve problems in conjunction with calculus, just as I was. Sometimes the professional ME has to be the first one to derive the answer so others can then look up what he/she did.
Reply:I realize I'm a little late to this thread but I have some opinions I'll throw out there. I'm a mechanical engineer, and honestly I could show someone how I do one design (like a gantry crane), but a different design would be just that, different. Design only becomes simple when you understand all the failure modes you can know by experience aren't going to come into play. You have to know a lot of things that don't apply to be confident in knowing the few that do. I took trigonometry and 4 semesters of calculus which I view as absolutely essential, 2 semesters physics which maybe aren't as essential but pretty useful, statics, dynamics, strength of materials, materials and manufacturing methods, mechanical design, and vibrations (which are all critical knowledge before embarking on a mechanical design in my opinion).That certainly doesn't mean you can't just overbuild without any calculation and every home project requires a PE stamped drawing. You have to consider what the cost of failure is and decide if you're ok with a risk of failure.Finite element analysis - what some CAD packages do - only tell you what you ask them. The first thing we learned about these systems in school is "garbage in = garbage out." Basically, you have to know the load cases, boundary constraints, etc that apply, and the appropriate assumptions that apply to get anything useful from FEA. And generally, you have to know how to do some hand calculations to make sure what the computer is telling you is reasonable.In my current job, I get to design things that absolutely have to work the first time. I enjoy it, but when human safety is at stake, I am exceedingly cautious. I don't care if I get accused of over engineering something or it costs a few more dollars for 8x3x3/8 HSS when 1/4 "would probably be fine," or it takes more time to do a 1/4 bevel and then a 3/8 weld on top of that, my name is attached to it and it's my responsibility to know it's going to work (and I use a heck of a lot more than 10% over what is required).That does not mean a good design can never fail. Anything can be overloaded, used improperly and fail or wear out prematurely. Some duty rests in the user to know the limitations of what they're using.I don't mean to come off as arrogant or prideful. I do enjoy what I do and take pride in my profession.Sent from my moto g(6) using Tapatalk
Reply:
Originally Posted by TWeatherford
Iere. I'm a mechanical engineer, I took trigonometry and 4 semesters of calculus which I view as absolutely essential, 2 semesters physics which maybe aren't as essential but pretty useful, statics, dynamics, strength of materials, materials and manufacturing methods, mechanical design, and vibrations (which are all critical knowledge before embarking on a mechanical design in my opinion).Thalk
Reply:Ohhh, here we go
Reply:
Originally Posted by 123weld
TWeatherford, you sound educated, i'm curious, during this education, was the trade centers that fell on 911, ever discussed/explained ? also, whats your thoughts/reason how they fell
Reply:By that reply I might guess you and 123weld think similar
Reply:
Originally Posted by ronsii
By that reply I might guess you and 123weld think similar
Reply:
Originally Posted by TWeatherford
My education started long before college both in school, under the hoods of cars and trucks, building things from wood and metal, continued in college, and continues today. Sent from my moto g(6) using Tapatalk
Reply:
Originally Posted by OMB
I'm guessing that is the case for almost all of us here, I re.
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Originally Posted by William McCormick
Software is not even close to solving mechanical problems. A human mind is equivalent to a billion computers working for years on a problem if the human has been actively exposed and properly sorting data. Sincerely, William McCormick |
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发表于 2021-9-1 23:14:31