I have a 30' x 60 ' Shop. I want to build a bridge crane over one half of it. I have enough W8 x 36 for all the legs and the top caps for the east-west run which will be 30 foot. I have a W16 x 36 by 30 foot long for the north-south bridge beam. My question is how strong would the W16 x 36 be for the span over the distance. If it is not good for at least 3000 lbs then I think I may be wasting my time. All the beams would need to be cut to length and plates welded on the ends and such, but that is not a problem. I have looked around and no one can tell me what the strength of the span would be. Is there anyone here that can help me out. Ben
goggle may be your friend here. I believe there are span tables available on the internet. Good luck, Dave.
I have not had much luck looking so far for i-beam strengths. There are a lot of variables such as how it is mounted but am hoping to find something.
I would think some steel mfrs would be able to help. Go to a supplier, tell them what you need and they can look it up.
Doing some quick back of the envelope math, A 30 ft W16x36 simply supported I beam will support 9500 lbs hung from the center point (worst case) with a factor of safety of 2. The factor of safety is used to mitigate material defects, weld / heat damage, etc (In other words, a perfect beam would support 19,000 lbs right before it begins to yield). Hope this helps.
Call your local metal supply and ask them. They will have this info. Tell them the span you want to go, that it will have a post at each end under it (or whatever the real scenario is) and that you want to hang 4000lbs from the center of it. They will tell you how big the material needs to be to handle that. No problem. If your local supplier can't help, call Industrial Metal Supply at (818) 729-3333‎
If I were you I would call a local structural engineer to run you up some calcs. For a few hundred bucks the peace of mind would be worth it. Is your steel 36 ksi or 50 ksi? What about the footings? What are you using for rails? Designed for impact loading? What seismic zone are you in?
Make sure you tie the wheels on one side to the wheels on the other side with an axle so it doesn't crab when you walk it. I worked for a guy that built one similar to this and it would travel over 5 bays. Pretty cool ****.
I strongly agree with NoSurf, finding out you under built it while having a weight on it is too late. From your first post you have no idea what you're getting yourself into. I also doubt any steel supplier will be willing to offer you any advice once they find out what you're trying to do. If something were to happen they could be hauled in as a co-defendant in a law suit. Spend the extra bucks, hire an engineer for advice and make it safe for you and anyone that might be around it.
There are ALOT of other factors to consider besides yeild strength...like deflection, connection strength, etc. I would strongly advise you to find a structural engineer. Try finding a teacher at a local university who will be able to tell you what your set-up will hold, what type of connection you will need, and give you advice on what kind of foundations you will need. BETTER SAFE THAN SORRY, and they probabaly won't charge you that much for it. I don't know your background Frozen Merc, obviously you've been through the AISC steel manual before. I don't mean to question anyone's credibility (you might be a structural engineer) but i wouldn't want anyones injuries/death on my karma LISTEN TO NOSURF...occupation listed in profile STRUCTURAL ENGINEER!!!!!
Elaborate on that comment please. I have built a couple of bridge cranes at the mine where I work. Granted they enginereed and pre fabbed. As far as doing the welding and fabrication on one for my shop I can do that without any safety issues. I am just trying to build one with what I already have.
At each end of the "Bridge" beam there will be a perpendicular foot with wheels under it. The way I am going to prevent it from crabbing is by putting the wheels in a piece of upside down channel iron. That way they track straight.
No offense taken. I am a trained Mechanical Engineer. I stated a simply supported beam as this is a hypothetical situation for "quick back of the envelope" math. I just wanted to see if his 3000 lbs was reasonable for the span. But you are correct, there are alot of other things to consider, and a qualified structural engineer will look at eveything from the supports, beams, weldments, gussets, etc that goes into a structure of this magnitude. A few hundred dollars to hire a Professional Engineer is money well spent to do it right.
My beam is 16" tall. Flange is 7" wide and 1/2" thick. The web is 1/4". According to a chart I found on the net it is heavier than the W16 X 36 but not quite as heavy as the W16 X 40. So to err on the safe side I am just calling it a W16 X 36. Of course free advice on the let is sometimes worth what you pay for it or less.
Steel 36 ksi or 50 ksi ? Not sure Footings will be a piece 1/2" plate welded to the bottom of the W8 X 36 legs. It will be sitting on 6 inches of fiber reinforced 4000 psi concrete. Rails (Top Caps) are W8 X36. Designed for impact loading ? Hopefully it will hold a motor/****** as it moves around installing/removing them. Seismic Zone? Elko, Nevada Northeast Corner
You're asking questions about a project that is going to take quite a bit of engineering to build so it operates correctly and safely. If something like a bridge crane is not properly engineered and ***embled a failure could be catastrophic. From posts from people far more knowledgeable than me, there seems to the importance of the proper type of materials used, using whatever you have on hand might not be enough. Just simply getting stress values isn't going to be enough, IMO. I build and install industrial machine controls from engineered drawings supplied to me by my customers. I would never try to design a complex control system because I don't have knowledge to safely do so. If you build this type of machine at work that was designed by a trained engineer why don't you ask one to help with designing the one you want to build. As I stated in my first post, if you have a failure there could be good potential for serious damage and injury.
I am in agreement with you on building it right. If the materials I have on hand are not suitable to do the job I will simply not do it untill I can get the proper materials.
Have you thought about a rolling A frame instead? FWIW given the high consequence of crane accidents, I'd want my insurance company to be cool with it. A couple hundy to get a certified engineer's stamp of approval might be the only way to get it covered. Something portable (A frame) probably doesn't have that limitation, even if it's huuuuge. good luck
FWIW some crane manufacturers offer kits, primarily end trucks for the bridges, in several capacities. You supply the raw steel. Might be worth checking out to see how it compares with your expected cost for fabricating same. That part of the engineering would already be done. Most easily found by searching on line material handling houses.
a little off topic but if you go through with this crane i wanna see pics when its done..... it sounds pretty impressive
There are hundreds... maybe thousands... of used bridge cranes sitting at used machinery and equipment dealers around the country. I went to an industrial auction last winter and they had 100 jib cranes and 20 or so bridges cranes offered at one sale... the bridge cranes went for as little as $300.00!!! Do some Google research and you can probably find what you need cheaper and better than you could build yourself.
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