A question for you crane guys (real) - General Topics - DHS Forum

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I was wondering on the capcity of a crane. When it says its a 35ton crane, does that mean it canlift 35 tons right next to the truck, or something different. Thanks

treeman
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from what i understand, 35t is its max lifting capacity at its "best picking point" whatever that would be, you would have to read the load chart, but im not an operator so someone can feel free to correct me on whatever i was wrong on
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A 35t can pickup 35t at about 2.5m radius

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A 35 ton crane will pick 35 tons with the shortest amount of boom and boomed almost straight up. Another way of judging cranes is called load-movement. Then there is also the old Power Crane and Shovel rating but I am not sure if they still do that.
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todd s,

I think the correct terminology is load-moment.



treeman,

Not sure what you intend to do with this information, perhaps it is just personal knowledge which is great. The information provided by renaultman is correct for those cranes operated in areas that utilize the metric system, (wish the United States did). Anyway, do partly to the unit of measure and slightly different standards in the United States, the maximum capacity of most cranes are measured at a radius of ten (10) feet. Also keep in mind that this ten (10) feet is measured from the center of rotation or the center pin.

Randy M. Smolenack

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our lmt is rates as 265 us tons. the most we have picked is 100 tons right off the rear deck. to pick 265 tons it would have to be rigt off the side between the out riggers, against the crane. now what would weigh 265 tons, and be small enough to get that close im still not sure of.
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I have always smiled at the capacity that cranes are rated at. I guess its just part of the sales pitch.

A 500 ton crane could theoretically lift that weight at its optimum point but will never likely do it for obvious reasons but is capable of it.

I know one occasion where I worked with a 350 ton crane that was installing steelwork that was able to be picked up by four men yet was not far off of its limit due to the height and radius it was placing it. A smaller one could not have done it so we needed the said crane to do it. No other way it could have been done other than use a helicopter!

I guess that most scenarios are the same with the large capacity cranes...not so much the weight but the distances involved.
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Thanks guys. Just for my own knowledge really. We did another crane job yesterday and the crane was a 35 ton. For the trunk piece we had to cut a chunk off that was too heavy for it too lift, even though the it weight 14,000 lbs after we cut a chunk off. It was hard to tell from the pics (I was in school) but Dad said even the operator said it was good the first time. Baffled me as to why a machine that could pick up 70,000lbs had a problem with 14,000lbs. Heres the link to my photobucket account for anyone that wants to view the pics.

http://s172.photobucket.com/albums/w40/trreewild/Our%20second%20crane%20job/?start=0

thanks again

treeman


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A little more knowledge to share with you, The closer a crane safely get to a lift the better . As mentioned above the cranes rating is what it'll pick mainly off the back with no boom extended out. Each manufacturer is different though. The further away (radius) the load's center of gravity gets from the crane the more critical the job gets.Try picking up a 50lb bag of readymix concrete and hold it next to your chest. It shouldn't be that hard. Then try holding it with your arms fully extended out and see how that works. That's kind of what it's like with handling a heavy piece at a far distance (radius) with a crane
I've operated cranes for 12 years now and you'd be surprised just how many people think a 70ton crane can place a 70 ton load 70ft away from the crane. That's a job for something around a 500ton machine to do
Dave
Nothing is impossible,,just difficult....
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RMS Models wrote:todd s,

I think the correct terminology is load-moment.


Ah yes, thank you.

drdcco wrote:
I've operated cranes for 12 years now and you'd be surprised just how many people think a 70ton crane can place a 70 ton load 70ft away from the crane. That's a job for something around a 500ton machine to do
Dave

Yes I run into this ever so often with engineers and other people in the construction industry. The best ever was I had a young dumb engineer tell me "if that crane can pick up 200 tons it can damn well push that can into the ground". Rank: Advanced Member
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I read the load charts with interest from Manitowoc.Thanks for the 'real' life exp.I had been self employed with my father in a small construction business.We at times had to work with professionals,architects,engineers etc. I believe that in their training they need a sort of 'residency'.Shovel stone,wheel concrete,work in a ditch,mix concrete by hand,lift tot handle heavy timbers,nail forms.see feel waht actual construction is all about and not from a desk or print.I started wheeling concrete when i was 12 and carrying shingles,lumber,mud,cold, heat ,rain.Just my 2cts.I also have a BA(bullshot allowance). Bob
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Hi !

My 02 cents , is that the cranes should have an international rating for all countrys ,
also we should have the rating of the tonnage will all outrigger out all boom out and alss all luffing jib out and then the real weigth they can bear !! like a chain you allways have the rate on the weaker link , then after you can give the other ratings .

What does a 500 tons crane means if you have to lift it 2.5m from the center pin ??? will anyone ever need that = NO

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Say The Liebherr LTM's max capacity is 500ton and its road weight is 160ton!
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This will answer all your questions. www.ainscough.co.uk/pdf/capacity_guide.pdf

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Whats the difference? There is so many variations to cranes. If a New Manitowoc 999 with max stick, max luffer at max radius can pick 500 lbs should the crane be rated at 500lbs? To me it doesn' matter what a crane is rated at. You still have to consult the chart. Does it matter which way you go. Rank: Advanced Member
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the average crane over 250 ton(u.s.) has over 350 pages of load charts,because of all the configurations-main boom length,fixed jib length&offset angle,luffing jib length,fixed jib length&offset angle attached to a luffing jib . then all of the different counter weight set-ups that could be used, such as a set up in series 1,2or3. the large hydraulic truck cranes are the worse,you have to compare capacities for the boom length that you decided on to determine the boom section sequence (boom section % of extension that will give you the most capacity at the needed radius,you don't just squirt a bunch of boom out.most of the newer machines automatically set the boom after you program in the sequence you want,and you have to do before you pick the load,so if you can't get the load where it has to go you haven't done your homework.the newer hydro's also have different charts for % of outrigger extension(0,50,100%). every manufacturer has their own system[gimmick!!] manitowoc-maxer,maxspander(old),ringer.demag has superlift,liebherr-has the ty guy system,derrick& buggy.adding all the different aux. counterweight combos you can use with these becomes pretty involved locating the right chart
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kat09 wrote:the average crane over 250 ton(u.s.) has over 350 pages of load charts,because of all the configurations-main boom length,fixed jib length&offset angle,luffing jib length,fixed jib length&offset angle attached to a luffing jib . then all of the different counter weight set-ups that could be used, such as a set up in series 1,2or3. the large hydraulic truck cranes are the worse,you have to compare capacities for the boom length that you decided on to determine the boom section sequence (boom section % of extension that will give you the most capacity at the needed radius,you don't just squirt a bunch of boom out.most of the newer machines automatically set the boom after you program in the sequence you want,and you have to do before you pick the load,so if you can't get the load where it has to go you haven't done your homework.the newer hydro's also have different charts for % of outrigger extension(0,50,100%). every manufacturer has their own system[gimmick!!] manitowoc-maxer,maxspander(old),ringer.demag has superlift,liebherr-has the ty guy system,derrick& buggy.adding all the different aux. counterweight combos you can use with these becomes pretty involved locating the right chart

...wow...how long does it take to figure out whether or not you can lift a load?
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Duty cycle cranes have a simpler set of guides to compare cranes. They use load x radius and also max suspended load at diffrent standard distances.


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...Thats why amatures "Untrained" don't make good crane operators. So many things effect capacity on a given lift its incredible. Distance from center, wind loading, height, etc. Nowdays most high-tech cranes will not allow you to lift or position a load that is beyond the rated capacity unless an override is used, and man those alarms will realy let you know that you are going in harms way! todd s Posted: Thursday, January 10, 10:13:27 PM
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TimT wrote:...Nowdays most high-tech cranes will not allow you to lift or position a load that is beyond the rated capacity unless an override is used, and man those alarms will realy let you know that you are going in harms way!

Yes but sadly it is very easy to wedge a penny in the override button and crane accidents continue to happen. Users browsing this topic