Saturday, March 11, 2017

Telescoping cranes can bend, but they should not break

When the boom of a telescoping crane is extended to its full reach, there is very little metal overlapping at the joints. I have always wondered how they avoid bending. The answer is that they are evidently designed to safely handle some bend. (I'm being vague about where I got some of these Facebook pictures because there were some comments that were not "family friendly.")

From Facebook

From Facebook

From Facebook
[Actually, I don't see much bend in this one.]
From Facebook
From Facebook
From Facebook
Leon Stravers posted
Mike Dicenzo Have you ever seen one heated from one side by the sun and it curves sideways ? Look's really bad !!
McKenzie K Andrew Pretty typical in a grove
Anthony Cammack Or a liebherr, or a Demag, or pretty much all longer hyd. Pinning booms-
McKenzie K Andrew Anthony Cammack grove is by far more deflective than the others you mentioned
Butch Gray commented on Leon's post
Every day occurance
Brad Young commented on Leon's post
Yep they flex

Kevin Mitchell posted
Grove 6300L

One of five photos posted by James Touhy
6300L erecting Potain White Plains NY

Philippe Dumas posted two photos with the comment: "GMK 6300L lifting Air compressor to the lake ground from the dam 74m main boom + 21m jib was necessary to reach radius."

My reaction was that the air compressor better be rather light with a radius that long.
Larry Winchester Jibs are for height, not radius.
Keith Havard Hope the pic of boom flexed is with load on hook.
Mike Newcomb lot of cable. [I wonder how much weight the cable itself adds to the load at the end of the boom.]
Mark Walker I'm thinking he maybe close to the end of the chart in that second pic looking from the rear

Justin Johnson posted
She wasn’t much to look at but she liked the abuse.
Jonathon Sisk commented on Justin's post
7000 pounds at 220' using a "250"
David Whitehead commented on Justin's post
The 5275's replacement, 5250L.
Johnny Karason Thomassen posted
I am gonna say tnx for my time in this group 😊 with a picture of what I thought this group was about 😊 7.8 tons on 50.6 meter GROVE GMK5250L

Tyler Widdifield commented on Johnny's post

But the operator needs to know the chart and avoid bending too much. It looks like they should have lifted the tower crane boom as two pieces. Note that as soon as the boom broke, the base lost its load, and it straightened right up.

Screenshot 2
Screenshot 1
Terex Cranes posted
Here's a great example of collaboration - Cropac Equipment Inc., C&C Crane, Total Crane Rental, and MTN Forming brought their expertise together on this Ontario waterfront project with Terex SK 315 and SK 415 tower cranes
[It looks like there is a bend in that boom to me. It also looks like the inner segments are only partially extended. I assume they are overlapping more steel at the base of the boom to try to reduce the bend.]
Balaji Mani posted
[Each segment is extended the same amount, but only about 2/3 of its length. I think there is a little bend in the boom.]
Frank Pintaro posted
Just a little boom deflection Gmk 5275
J.P. Duffy posted
Might be short rigging a couple pics tomorrow
[Building a Potain tower crane: "It will be a MDT219 10t 65m jib." There is a long discussion about "line pull." I don't know what they are talking about, and evidently the operator also does not understand either.]
J.P. Duffy posted three photos with the comment: "Just another day under the sun."



Rick Kleuskens posted
Toronto 23/09/17, one of 11 photos posted

This one is interesting because I do not notice a bend in the boom even though it was operating with a rather long radius.
Bay Crane posted
[It looks like there is a little bend in this one.]
Patrick M Harrison posted
Fish on!!
Brandon Leichinger commented on the above posting

John M. Childers commented on the above posting
I can relate!!!!
Devin Parsons posted
Fish on!!! 🎣🎣🎣🎣
Brandon L Grace commented on the above posting
Why yes.
Thomas Dearmond on the above posting
Brandon Owens commented on the above posting
Yes sir.
Brian Fogtmann posted
Manitowoc 5130-2
Butch Gray Gotta love deflection
Jacob Gibson posted four photos with the comment: "Testing the limits of our brand new LTM 1250-5.1."



A group added two photos. I'm surpised the boom broke in the middle of a segment rather than the near the end of the segment where the next segment's insertion ends.

Philippe Dumas posted three photos with the comment: "GMK 5250L"


Phillippe Dumas posted
GMK 5250L
Jim Paris I'm guessing that the charts say it's a good lift, but man that is an ugly looking boom angle!Philippe Dumas 70 + 21m jib at long radius = it seems normalPete Lefebvre With that jib probably lifting roofers styrofoam
Baoualem Kefif posted four pictures with the comment: "GMK6300L." His third photo shows that at a long radius, it looks like the boom bends under its own weight.

Luke Brower posted two photos with the comment: "From JJ Curran's page."
Luke Brower Need to reach from Detroit to Ohio looks like the crane for the job. 336' and no luffer.
Bill McCarthy If it didn't deflect , then I would start to worry .....


James Zampler posted three photos with the comment: "Love me some deflection!"


David Whitehead commented on James' posting
 When I load tested my 5250L.
Neil Frampton posted
Bit of deflection
William Gadbury What's that 20% off set ?Neil Frampton Yes William it’s 20 degrees offset with 5.4 ton at 25.7 metre radius mmmmm

[I wish I understood the "offset" terminology.]
Brady Buckland commented on the above posting
James Zampier posted
Just a little fishing today.
Michael Singleton Nice deflection shot.
Master Britt Lipscomb posted
GMK 5240
Jahanzeb Afzal posted
[Building a tower crane. If the city would have let them block a traffic lane, they could have used a cheaper hydro because it would have been closer to the tower.]
Kevin Mitchell posted
Grove 6300L... lifting 12.5 ton( 27500lb) for you lot over the pond..75m(250ish ft)boom at 30.4 m (102ft ish) radius... the pic really does not do it justice..hoisted load down just to see how much deflection was there and she came back 7.3 m( 24ft)
Bill Sharp That’s normal they are made to do that or the boom would snap
Graham Morris commented on Kevin's posting
Bendy bendy
Dustin McGovney commented on Kevin's posting
Louis DeFazio commented on Kevin's posting, cropped
Brad Young commented on Kevin's posting
Bendy bendy bendy
Anthony Perrotta posted
Tms 9000-2 in syracuse ny
Clint Johnson I love seeing pics that really show boom deflection. I was under the hook of a 250t all out with jib and aux stinger. Thing looked like a fishing pole with a big one on it.
Steve Wilson Nice! Jamesville trash plant?
Anthony Perrotta Yes sir
Anthony commented on his posting
Yeah it's impressive for sure. Here's another -2 with the insert and luffer in it
Walter Hansen shared
Ben Longman Amazing the boom didn’t snap....
It does demonstrate how strong these cranes are when they tip over. Usually the boom and the outriggers remain intact.
Screenshot @ -0:19 (source)

J.P. Duffy posted
Name that banana
Michael Reich Tms9000e-2

Bay Crane posted
Briand Jones The beginning of a crane rainbow.Jonathan Cummings Cranebow, work on your comments.Marco Santoro All that sweet boom deflection without showing us what's on the hook.... so not fair @bay CraneThomas Hagans Jon Shrock stretched outJon Shrock Thats gotta be around 200-225 radius
Chris A Baez commented on Bay Crane's posting
Dale Lanham Damn I didn’t realize they bowed that much!Scott Lozier They bend like a fly rod.Joey Colicchio Normal for a 275/300 long boom with jib...just looks scary
Clayton Chaban posted
Jr Lemasters commented on Clayton's posting
Trevor Crawford commented on Clayton's posting
Brad Young commented on a posting

Matt Helms posted
A little fishing today in KC.
4400 gross @ 255’
Ben Mason posted
dismantling tower in Brisbane Australia
First of ten photos that Wynand Louw Smit shared
Dismantle Potain MD90
[There are a lot of comments about the twisted cable. I didn't notice it until I started reading the comments.]
Matteo Serra shared

Skip the first minute of this video, then you can watch the boom bend up and down.

Bending to the side!

Nick Beaman posted
First time for everything. Been working with the sun only on one side and it heated up one side so bad the cable came off the boom guides. This pic is after 15 minutes of sun on the opposing side.
Diane Martin We got Solar deflection on our Liebherr here in Arizona.
Paul Gonter Had something similar happen on hundred ton grove. The guides in boom were out of adjustment. Not a pretty sight. Could look up and see cable as a stringline showing curve in boom.

Jared Marcotte posted
Our GMK 6300l getting busy yesterday!
Stephen Spencer If it's not flexing, it's not working.Jim Ball I KNOW they’re designed that way - I KNOW THAT - but it still creeps me out!Gary M Hardin That’s a little too much arc for my comfort.


1, cropped

2, cropped
Posted, cropped
Craig Harry Cameron Derek Manns seen one of these before ?Derek Manns No never broken like that.Garrett Larkin Brian Boudreau I'm not even sure how.Brian Boudreau KATO's new series of knuckle picker.

[It looks like Kato needs to go back to the drawing board 
(actually, the computer screen) and add some steel to the main boom. The problem with computer aided design is that it allows the engineers to build with less steel than they did in the pencil and paper days. That improves the cost of building, but lowers the margin of safety.]
Jeff Funk Looks like rotec failure ouch
[This is the first time I have seen a photo of the attachment of the house to the truck failing. Normally the truck tips over if the load is off the chart.]
Chuck Ellis posted

Casey Van Beekum That may be the dumbest thing I seen that took some effort of stupidity those little cranes are pretty tuff even with the wrong configuration they will usually float first.
[I gather from some other comments that "float" means an outrigger will start to lift off its pad.]
The first time I have seen the failure point being a hydraulic ram:
Chuck Ellis posted
[Well, the boom didn't break, but there is obviously a heavy load that still hasn't touched ground. Given the low boom angle, the radius was probably off the chart for the weight of the load.]
Chuck Ellis posted
[The boom did not break even though it was obviously under a lot of stress.]
Carlos Felipe commented on Richard Dobbelaire's post
If u r not bending u are just pretending!!
[From the context, I think it is a Grove 6300L-1.]
Screenshot from a Scott Schisler video for which I don't know how to get a link
The video is a comment on Richard Dobbelaire's post
Chuck Ellis posted
Brian Eisenhart Finally...a full CW tipper. I'm impressed.
Scott Shumake Crane works murfreesboro tn I do believe
[It is a testament to the strength of a hydro crane that they remain intact in many of the tipping accident photos I see. The comments indicate that he may be able to salvage this by simply hoisting down slowly. It looks like it didn't even damage the building. Actually, the building probably saved the crane.]

Lonzie commented on a post
6300l 282ft

S S Dhami Dhami posted
Terex ac 300 tons
[This is the most bend I remember seeing with such a high boom angle.]

Screenshot @ -0:05
[It was the close crane that first started to tip.]

Jeff Corrie posted two photos:
Mike Weaver Bold Line.....
Richard Thomas Above the bold line is all structural and below the line is tipping or do i have it backwards??
Mark Adcock Richard Thomas you got it correct.Corkey Crane Those old Link-Belts are really stout machines. Looks like someone was waaaay overloading it!
Mitchell Gomez Caisson removals is what did it.
Corkey Crane Yep, that'll do it! Personally, I wouldn't use anything but a crawler to pull caisson tubes.
Chris Johnson I hate doing anything foundations related with a hydraulic. I see pinned-boom cranes doing tings like this and absolutely cringe.
Mitchell Gomez Shaun Sedam as in construction safety is a facade. It looks good while reporters and the media are watching but many times I have heard can’t you push it we need this truck unloaded. It’s outside of the charts I would say. They would rather blame the operator then take responsibility in any way shape or form. The operator of the Big Blue Lampson that went down killing three iron workers has to live with his part even though he felt the wind was an issue and the pick should be put off until wind conditions were better.


Mark Crane posted
Erik Mccartney here we see the elusive mating dance of the RT crane its very rare to witness such a dance since you usually only see one at any given time.
Al Kurtz I imagine one operator didn’t lift his share of the load so when the overloaded crane lost it, The other went as well.
Sourav Sehdev Al Kurtz i think you are right.
Doc Bailey I could have bet money without seeing them that they were good old Terex steel. From China.

Jimmy Feiden And that boys and girls, is the difference between structural capacity and stability.
Jimmy Feiden "Awwwww hell! You ain't light yet. Get up on it!"
[I think he means that just because the crane is not close to tipping does not mean that it can handle the load.]

The first 30 seconds of this video is interesting. It shows that the boom needs to be raised as it bends underload. It is selling a computer to do the compensation. All of the comments felt strongly that another computer is not needed because any decent crane operator can "hold radius." (source)

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